@article{cooper_sobolik_kovacevic_rock_sajewski_guest_lopman_jaykus_leon_2023, title={Combined Infection Control Interventions Protect Essential Food Workers from Occupational Exposures to SARS-CoV-2 in the Agricultural Environment}, ISSN={["1098-5336"]}, DOI={10.1128/aem.00128-23}, abstractNote={This is the first study to estimate the daily risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection across a variety of indoor and outdoor environmental settings relevant to food workers (e.g., shared transportation [car or bus], enclosed produce processing facility and accompanying breakroom, outdoor produce harvesting field, shared housing facility) through a linked quantitative microbial risk assessment framework. Our model has demonstrated that the elevated daily SARS-CoV-2 infection risk experienced by indoor and outdoor produce workers can be reduced below 1% when vaccinations (optimal vaccine efficacy, 86 to 99%) are implemented with recommended infection control strategies (e.g., handwashing, surface disinfection, universal masking, physical distancing, and increased ventilation).}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Cooper, D. Kane and Sobolik, Julia S. and Kovacevic, Jovana and Rock, Channah M. and Sajewski, Elizabeth T. and Guest, Jodie L. and Lopman, Ben A. and Jaykus, Lee-Ann and Leon, Juan S.}, year={2023}, month={Jun} }
 @article{escudero-abarca_goulter_manuel_leslie_green_arbogast_jaykus_2022, title={Comparative Assessment of the Efficacy of Commercial Hand Sanitizers Against Human Norovirus Evaluated by an in vivo Fingerpad Method}, volume={13}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2022.869087}, abstractNote={Human noroviruses (hNoV) are the leading cause of acute non-bacterial gastroenteritis worldwide and contaminated hands play a significant role in the spread of disease. Some hand sanitizers claim to interrupt hNoV transmission, but their antiviral efficacy on human hands is poorly characterized. The purpose of this work was to characterize the efficacy of representative commercial hand sanitizers against hNoV using an in vivo fingerpad method (ASTM E1838-17). Eight products [seven ethanol-based and one benzalkonium chloride (BAK)-based], and a benchmark 60% ethanol solution, were each evaluated on 10 human volunteers using the epidemic GII.4 hNoV strain. Virus titers before and after treatment were evaluated by RT-qPCR preceded by RNase treatment; product efficacy was characterized by log 10 reduction (LR) in hNoV genome equivalent copies after treatment. The benchmark treatment produced a 1.7 ± 0.5 LR, compared with Product A (containing 85% ethanol) which produced a 3.3 ± 0.3 LR and was the most efficacious ( p < 0.05). Product B (containing 70% ethanol), while less efficacious than Product A ( p < 0.05), performed better than the benchmark with a LR of 2.4 ± 0.4. Five of the other ethanol-based products (labeled ethanol concentration ranges of 62–80%) showed similar efficacy to the 60% ethanol benchmark with LR ranging from 1.3 to 2.0 ( p > 0.05). Product H (0.1% BAK) was less effective than the benchmark with a LR of 0.3 ± 0.2 ( p < 0.05). None of the products screened were able to completely eliminate hNoV (maximum assay resolution 5.0 LR). Product performance was variable and appears driven by overall formulation. There remains a need for more hand sanitizer formulations having greater activity against hNoV, a virus that is comparatively recalcitrant relative to other pathogens of concern in community, healthcare, and food preparation environments.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Escudero-Abarca, Blanca I. and Goulter, Rebecca M. and Manuel, Clyde S. and Leslie, Rachel A. and Green, Kristen and Arbogast, James W. and Jaykus, Lee-Ann}, year={2022}, month={Apr} }
 @article{sobolik_sajewski_jaykus_cooper_lopman_kraay_ryan_leon_2022, title={Controlling risk of SARS-CoV-2 infection in essential workers of enclosed food manufacturing facilities}, volume={133}, ISSN={["1873-7129"]}, DOI={10.1016/j.foodcont.2021.108632}, abstractNote={The SARS-CoV-2 global pandemic poses significant health risks to workers who are essential to maintaining the food supply chain. Using a quantitative risk assessment model, this study characterized the impact of risk reduction strategies for controlling SARS-CoV-2 transmission (droplet, aerosol, fomite-mediated) among front-line workers in a representative indoor fresh fruit and vegetable manufacturing facility. We simulated: 1) individual and cumulative SARS-CoV-2 infection risks from close contact (droplet and aerosols at 1-3 m), aerosol, and fomite-mediated exposures to a susceptible worker following exposure to an infected worker during an 8 h-shift; and 2) the relative reduction in SARS-CoV-2 infection risk attributed to infection control interventions (physical distancing, mask use, ventilation, surface disinfection, hand hygiene, vaccination). Without mitigation measures, the SARS-CoV-2 infection risk was largest for close contact (droplet and aerosol) at 1 m (0.96, 5th - 95th percentile: 0.67-1.0). In comparison, risk associated with fomite (0.26, 5th - 95th percentile: 0.10-0.56) or aerosol exposure alone (0.05, 5th - 95th percentile: 0.01-0.13) at 1 m distance was substantially lower (73-95%). At 1 m, droplet transmission predominated over aerosol and fomite-mediated transmission, however, this changed by 3 m, with aerosols comprising the majority of the exposure dose. Increasing physical distancing reduced risk by 84% (1-2 m) and 91% (1-3 m). Universal mask use reduced infection risk by 52-88%, depending on mask type. Increasing ventilation (from 0.1 to 2-8 air changes/hour) resulted in risk reductions of 14-54% (1 m) and 55-85% (2 m). Combining these strategies, together with handwashing and surface disinfection, resulted in <1% infection risk. Partial or full vaccination of the susceptible worker resulted in risk reductions of 73-92% (1 m risk range: 0.08-0.26). However, vaccination paired with other interventions (ACH 2, mask use, or distancing) was necessary to achieve infection risks <1%. Current industry SARS-CoV-2 risk reduction strategies, particularly when bundled, provide significant protection to essential food workers.}, journal={FOOD CONTROL}, author={Sobolik, Julia S. and Sajewski, Elizabeth T. and Jaykus, Lee-Ann and Cooper, D. Kane and Lopman, Ben A. and Kraay, Alicia N. M. and Ryan, P. Barry and Leon, Juan S.}, year={2022}, month={Mar} }
 @article{kirchner_everhart_doring_smits_faircloth_duong_goulter_goodson_shelley_shumaker_et al._2022, title={Cross-Contamination to Surfaces in Consumer Kitchens with MS2 as a Tracer Organism in Ground Turkey Patties}, volume={85}, ISSN={["1944-9097"]}, DOI={10.4315/JFP-22-060}, abstractNote={It is estimated that one in five cases of foodborne illnesses is acquired in the home. However, how pathogens move throughout a kitchen environment when consumers are preparing food is not well characterized. The purpose of this study was to determine the prevalence and degree of cross-contamination across a variety of kitchen surfaces during a consumer meal preparation event. Consumers (n = 371) prepared a meal consisting of turkey patties containing the bacteriophage MS2 as a tracer organism and a ready-to-eat lettuce salad. Half were shown a video on proper thermometer use before the trial. After meal preparation, environmental sampling and detection were performed to assess cross-contamination with MS2. For most surfaces, positivity did not exceed 20%, with the exception of spice containers, for which 48% of the samples showed evidence of MS2 cross-contamination. Spice containers also had the highest MS2 concentrations, at a mean exceeding 6 log viral genome equivalent copies per surface. The high level of MS2 on spice containers drove the significant differences between surfaces, suggesting the significance of spice containers as a vehicle for cross-contamination, despite the absence of previous reports to this effect. The thermometer safety intervention did not affect cross-contamination. The efficiency of MS2 transfer, when expressed as a percentage, was relatively low, ranging from an average of 0.002 to 0.07%. Quantitative risk assessment work using these data would aid in further understanding the significance of cross-contamination frequency and efficiency. Overall, these data will help create more targeted consumer messaging to better influence consumer cross-contamination behaviors.HIGHLIGHTSForty-eight percent of spice containers sampled showed evidence of MS2 cross-contamination.Spice containers had the highest MS2 concentrations across kitchen surfaces.Spice containers may be a key vehicle for cross-contamination.The thermometer safety intervention did not affect cross-contamination.The efficiency of MS2 transfer was relatively low, ranging from 0.002 to 0.07%.}, number={11}, journal={JOURNAL OF FOOD PROTECTION}, author={Kirchner, Margaret and Everhart, Savana and Doring, Lindsey and Smits, Caitlin and Faircloth, Jeremy and Duong, Minh and Goulter, Rebecca M. and Goodson, Lydia and Shelley, Lisa and Shumaker, Ellen Thomas and et al.}, year={2022}, month={Nov}, pages={1594–1603} }
 @article{sobolik_sajewski_jaykus_cooper_lopman_kraay_ryan_guest_webb-girard_leon_2022, title={Decontamination of SARS-CoV-2 from cold-chain food packaging provides no marginal benefit in risk reduction to food workers}, volume={136}, ISSN={["1873-7129"]}, DOI={10.1016/j.foodcont.2022.108845}, abstractNote={Countries continue to debate the need for decontamination of cold-chain food packaging to reduce possible severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) fomite transmission among frontline workers. While laboratory-based studies demonstrate persistence of SARS-CoV-2 on surfaces, the likelihood of fomite-mediated transmission under real-life conditions is uncertain. Using a quantitative microbial risk assessment model of a frozen food packaging facility, we simulated 1) SARS-CoV-2 fomite-mediated infection risks following worker exposure to contaminated plastic packaging; and 2) reductions in these risks from masking, handwashing, and vaccination. In a frozen food facility without interventions, SARS-CoV-2 infection risk to a susceptible worker from contact with contaminated packaging was 1.5 × 10−3 per 1h-period (5th – 95th percentile: 9.2 × 10−6, 1.2 × 10−2). Standard food industry infection control interventions, handwashing and masking, reduced risk (99.4%) to 8.5 × 10−6 risk per 1h-period (5th – 95th percentile: 2.8 × 10−8, 6.6 × 10−5). Vaccination of the susceptible worker (two doses Pfizer/Moderna, vaccine effectiveness: 86–99%) with handwashing and masking reduced risk to 5.2 × 10−7 risk per 1h-period (5th – 95th percentile: 1.8 × 10−9, 5.4 × 10−6). Simulating increased transmissibility of current and future variants (Delta, Omicron), (2-, 10-fold viral shedding) among a fully vaccinated workforce, handwashing and masking continued to mitigate risk (1.4 × 10−6 - 8.8 × 10−6 risk per 1h-period). Additional decontamination of frozen food plastic packaging reduced infection risks to 1.2 × 10−8 risk per 1h-period (5th – 95th percentile: 1.9 × 10−11, 9.5 × 10−8). Given that standard infection control interventions reduced risks well below 1 × 10−4 (World Health Organization water quality risk thresholds), additional packaging decontamination suggest no marginal benefit in risk reduction. Consequences of this decontamination may include increased chemical exposures to workers, food quality and hazard risks to consumers, and unnecessary added costs to governments and the global food industry.}, journal={FOOD CONTROL}, author={Sobolik, Julia S. and Sajewski, Elizabeth T. and Jaykus, Lee-Ann and Cooper, D. Kane and Lopman, Ben A. and Kraay, Alicia N. M. and Ryan, P. Barry and Guest, Jodie L. and Webb-Girard, Amy and Leon, Juan S.}, year={2022}, month={Jun} }
 @article{mertens_moore_jaykus_velev_2022, title={Efficacy and Mechanisms of Copper Ion-Catalyzed Inactivation of Human Norovirus br}, volume={8}, ISSN={["2373-8227"]}, DOI={10.1021/acsinfecdis.1c00609}, abstractNote={The antinoroviral effect of copper ions is well known, yet most of this work has previously been conducted in copper and copper alloy surfaces, not copper ions in solution. In this work, we characterized the effects that Cu ions have on human norovirus capsids' and surrogates' integrity to explain empirical data, indicating virus inactivation by copper alloy surfaces, and as means of developing novel metal ion-based virucides. Comparatively high concentrations of Cu(II) ions (>10 mM) had little effect on the infectivity of human norovirus surrogates, so we used sodium ascorbate as a reducing agent to generate unstable Cu(I) ions from solutions of copper bromide. We found that significantly lower concentrations of monovalent copper ions (∼0.1 mM) compared to divalent copper ions cause capsid protein damage that prevents human norovirus capsids from binding to cell receptors in vitro and induce a greater than 4-log reduction in infectivity of Tulane virus, a human norovirus surrogate. Further, these Cu(I) solutions caused reduction of GII.4 norovirus from stool in suspension, producing about a 2-log reduction of virus as measured by a reverse transcriptase-quantitative polymerase chain reaction. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) data indicate substantial major capsid protein cleavage of both GI.7 and GII.4 norovirus capsids, and TEM images show the complete loss of capsid integrity of GI.7 norovirus. GII.4 virus-like particles (VLPs) were less susceptible to inactivation by copper ion treatments than GI.7 VLPs based upon receptor binding and SDS-PAGE analysis of viral capsids. The combined data demonstrate that stabilized Cu(I) ion solutions show promise as highly effective noroviral disinfectants in solution that can potentially be utilized at low concentrations for inactivation of human noroviruses.}, number={4}, journal={ACS INFECTIOUS DISEASES}, author={Mertens, Brittany S. and Moore, Matthew D. and Jaykus, Lee-Ann and Velev, Orlin D.}, year={2022}, month={Apr}, pages={855–864} }
 @article{escudero-abarca_goulter_bradshaw_faircloth_leslie_manuel_arbogast_jaykus_2022, title={Efficacy of an alcohol-based surface disinfectant formulation against human norovirus}, ISSN={["1365-2672"]}, DOI={10.1111/jam.15479}, abstractNote={To evaluate the anti-noroviral efficacy of PURELL® surface sanitizer and disinfectant spray (PSS, an alcohol-based formulation) using human norovirus GII.4 Sydney [hNoV, by RT-qPCR and human intestinal enteroid (HIE) infectivity assay] and its cultivable surrogate, Tulane virus (TuV, infectivity assay), compared to sodium hypochlorite (NaOCl) solutions.PSS efficacy was evaluated in suspension and on surfaces [stainless steel (SS)] using ASTM methods. Results were expressed as log10 reduction (LR) of genome equivalent copy number (GEC, for hNoV, assayed by RT-qPCR) and plaque forming units (PFU, for TuV, per infectivity assay). In suspension, PSS achieved a 2.9 ± 0.04 LR hNoV GEC irrespective of contact time (30 or 60 s) and soil load (2.5% or 5%). Under all treatment conditions, infectious TuV could not be recovered following exposure to PSS, corresponding to the assay limit of detection (3.1-5.2 log10 PFU). Infectious hNoV could not be detected in the HIE model after exposure to PSS. On SS and 2.5% soil, PSS produced a 3.1 ± 0.1 LR hNoV GEC, comparable to 500 ppm NaOCl for 60 s. With 5.0% soil, PSS produced a 2.5 ± 0.2 LR hNoV GEC, which was similar to 1000-5000 ppm NaOCl for 60 s.PSS showed high anti-hNoV efficacy by RT-qPCR and in in vitro (TuV) and ex vivo (HIE) infectivity assays and performed similar to 1000-5000 ppm NaOCl for a 60-s contact time on SS with added soil.hNoV remains a significant cause of morbidity globally, partly due to its resistance to numerous surface disinfectants. RT-qPCR results from this study indicate PSS efficacy against hNoV is comparable to NaOCl efficacy. Infectivity assays leveraging TuV and the HIE model for hNoV support and confirm loss of virus infectivity. Collectively, these results indicate the product's ability to inactivate hNoV quickly, which could be beneficial in settings having elevated risk for hNoV transmission.}, journal={JOURNAL OF APPLIED MICROBIOLOGY}, author={Escudero-Abarca, Blanca I and Goulter, Rebecca M. and Bradshaw, Justin and Faircloth, Jeremy and Leslie, Rachel A. and Manuel, Clyde S. and Arbogast, James W. and Jaykus, Lee-Ann}, year={2022}, month={Feb} }
 @article{shumaker_kirchner_cates_shelley_goulter_goodson_bernstein_lavallee_jaykus_chapman_2022, title={Observational Study of the Impact of a Food Safety Intervention on Consumer Poultry Washing}, volume={85}, ISSN={["1944-9097"]}, DOI={10.4315/JFP-21-397}, abstractNote={This study was conducted to test the effectiveness of a consumer poultry washing educational intervention that included video observation of meal preparation with participants who self-reported washing poultry. Treatment group participants received three e-mail messages containing information that the U.S. Department of Agriculture has used on social media sites (video and infographics) related to poultry preparation, including advising against washing chicken. Participants were observed cooking chicken thighs (inoculated with traceable nonpathogenic Escherichia coli strain DH5α) and preparing a salad to determine whether they washed the chicken and the extent of cross-contamination to the salad and areas of the kitchen. After meal preparation, participants responded to an interview about food handling behaviors, including questions about the intervention for treatment group participants. Three hundred people participated in the study (158 control, 142 treatment). The intervention effectively encouraged participants not to wash chicken before cooking; 93% of treatment group participants but only 39% of control group participants did not wash the chicken (P < 0.0001). The high levels of E. coli DH5α detected in the sink and on the salad lettuce suggest that microbes transferred to the sink from the chicken, packaging, or contaminated hands are a larger cause for concern than is splashing contaminated chicken fluids onto the counter. Among chicken washers, 26 and 30% of the lettuce from the prepared salad was contaminated for the control and treatment groups, respectively. For nonwashers, 31 and 15% of the lettuce was contaminated for the control and treatment groups, respectively. Hand-facilitated cross-contamination is suspected to be a factor in explaining this resulting lettuce cross-contamination. This study demonstrates the need to change the frame of "don't wash your poultry" messaging to instead focus on preventing contamination of sinks and continuing to emphasize the importance of hand washing and cleaning and sanitizing surfaces.}, number={4}, journal={JOURNAL OF FOOD PROTECTION}, author={Shumaker, Ellen Thomas and Kirchner, Margaret and Cates, Sheryl C. and Shelley, Lisa and Goulter, Rebecca and Goodson, Lydia and Bernstein, Christopher and Lavallee, Aaron and Jaykus, Lee-Ann and Chapman, Benjamin}, year={2022}, month={Apr}, pages={615–625} }
 @article{luisana_saker_jaykus_getty_2022, title={Survey evaluation of dog owners' feeding practices and dog bowls' hygiene assessment in domestic settings}, volume={17}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0259478}, abstractNote={In-home pet food handling and food dish hygiene practices can have adverse health impacts for both humans and pets. Safe food and dish handling guidelines are not easily evidenced for pet owners. The study was designed to investigate dog owners' feeding habits and evaluate the impact of the Food and Drug Association (FDA) hygiene protocols on dog food dish contamination. Procedures and surveys were approved by North Carolina State University Institutional Animal Care and Use Committee and Institutional Review Board. Pet feeding and food dish hygiene data were collected from 417 dog owner surveys and 68 food dish swabs. Total aerobic plate counts (APC) were performed on 68 dishes and randomly assigned into Group A (FDA pet food handling and dish hygiene guidelines), Group B (FDA pet and human food handling and dish hygiene guidelines), or Group C (no guidelines). Hygiene protocols were instituted in-home for 1 week, followed by a second APC and follow-up survey. Survey from dog owners-households indicated: 4.7% were aware of FDA pet food handling and dish hygiene guidelines; 36% have individuals ≤ 13 years old and/or immunocompromised; 43% stored dog food 0-5 feet from human food; 34% washed their hands after feeding; and 33% prepared their dog food on human food preparation surfaces. The hygiene protocols followed by Groups A and B resulted in significant decreases in food dish APC (p<0.001; 1.4; (0.9, 2.0); p<0.05; 0.604 (0.02, 1.2), respectively), as compared to Group C (p≥0.05). Hot water (>160° F or 71.1°C) washing decreased APC (p<0.01; 1.5 (0.4, 2.6)) over cold/lukewarm water. In the follow-up survey, 8% of Group A and B respondents reported likely to adhere to protocols long-term. This study suggests a need for pet food handling and dish hygiene guideline education to minimize bacterial contamination of dishes, especially for high-risk populations.}, number={4}, journal={PLOS ONE}, author={Luisana, Emily and Saker, Korinn and Jaykus, Lee-Ann and Getty, Caitlyn}, year={2022} }
 @article{faircloth_goulter_manuel_arbogast_escudero-abarca_jaykus_2022, title={The Efficacy of Commercial Surface Sanitizers against Norovirus on Formica Surfaces with and without Inclusion of a Wiping Step}, ISSN={["1098-5336"]}, DOI={10.1128/aem.00807-22}, abstractNote={Human noroviruses (hNoVs) are the leading cause of acute gastroenteritis and food-borne disease worldwide. Noroviruses are difficult to inactivate, being recalcitrant to sanitizers and disinfectants commonly used by the retail food sector.}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Faircloth, Jeremy and Goulter, Rebecca M. and Manuel, Clyde S. and Arbogast, James W. and Escudero-Abarca, Blanca and Jaykus, Lee-Ann}, year={2022}, month={Aug} }
 @article{franco-frias_mercado-guajardo_merino-mascorro_perez-garza_heredia_leon_jaykus_davila-avina_garcia_2021, title={Analysis of Bacterial Communities by 16S rRNA Gene Sequencing in a Melon-Producing Agro-environment}, volume={82}, ISSN={["1432-184X"]}, DOI={10.1007/s00248-021-01709-8}, number={3}, journal={MICROBIAL ECOLOGY}, author={Franco-Frias, Eduardo and Mercado-Guajardo, Victor and Merino-Mascorro, Angel and Perez-Garza, Janeth and Heredia, Norma and Leon, Juan S. and Jaykus, Lee-Ann and Davila-Avina, Jorge and Garcia, Santos}, year={2021}, month={Oct}, pages={613–622} }
 @article{manuel_suther_moore_jaykus_2021, title={Comparison of a one-step real-time RT-PCR and a nested real-time RT-PCR for a genogroup II norovirus reveals differences in sensitivity depending upon assay design and visualization}, volume={16}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0248581}, abstractNote={Human norovirus (NoV) is the leading cause of acute viral gastroenteritis and a major source of foodborne illness. Detection of NoV in food and environmental samples is typically performed using molecular techniques, including real-time reverse transcription polymerase chain reaction (RT-PCR) and less frequently, nested real-time PCR. In this study, we conducted a controlled comparison of two published NoV detection assays: a broadly reactive one-step real-time RT-PCR and a two-step nested real-time PCR assay. A 20% human fecal suspension containing a genogroup II human NoV was serially diluted, genome extracted, and subjected to amplification using the two assays compared via PCR Units. Additional amplicon confirmation was performed by dot blot hybridization using digoxigenin (DIG)-labeled oligonucleotide probes. Both assays displayed similar amplification standard curves/amplification efficiencies; however, the nested assay consistently detected one log 10 lower virus. Dot blot hybridization improved the detection limit of the nested real-time PCR by one log 10 NoV genome copies but impaired the detection limit of the one-step real-time RT-PCR by one log 10 NoV genome copies. These results illustrate the complexities in designing and interpreting molecular techniques having a sufficient detection limit to detect low levels of viruses that might be anticipated in contaminated food and environmental samples.}, number={4}, journal={PLOS ONE}, author={Manuel, Clyde S. and Suther, Cassandra and Moore, Matthew D. and Jaykus, Lee-Ann}, year={2021}, month={Apr} }
 @misc{kirchner_goulter_chapman_clayton_jaykus_2021, title={Cross-Contamination on Atypical Surfaces and Venues in Food Service Environments}, volume={84}, ISSN={["1944-9097"]}, DOI={10.4315/JFP-20-314}, abstractNote={Cross-contamination of raw food to other surfaces, hands, and foods is a serious issue in food service. With individuals eating more meals away from home, contracting a foodborne illness from a food service establishment is an increasing concern. However, most studies have concentrated on hands or food contact surfaces and neglected atypical and unusual surfaces (surfaces that are not typically identified as a source of cross-contamination) and venues. This review was conducted to identify atypically cross-contaminated surfaces and atypical venues where cross-contamination could occur that have not been examined thoroughly in the literature. Most surfaces that could be at risk for cross-contamination are frequently touched, are rarely cleaned and sanitized, and can support the persistence and/or growth of foodborne pathogens. These surfaces include menus, spice and condiment containers, aprons and coveralls, mobile devices and tablets, and money. Venues that are explored, such as temporary events, mobile vendors, and markets, are usually limited in space or infrastructure, have low compliance with proper hand washing, and provide the opportunity for raw and ready-to-eat foods to come into contact with one another. These factors create an environment in which cross-contamination can occur and potentially impact food safety. A more comprehensive cleaning and sanitizing regime encompassing these surfaces and venues could help mitigate cross-contamination. This review highlights key surfaces and venues that have the potential to be cross-contaminated and have been underestimated or not fully investigated. These knowledge gaps indicate where further work is needed to fully understand the role of these surfaces and venues in cross-contamination and how it can be prevented.}, number={8}, journal={JOURNAL OF FOOD PROTECTION}, author={Kirchner, Margaret and Goulter, Rebecca M. and Chapman, Benjamin J. and Clayton, James and Jaykus, Lee-Ann}, year={2021}, month={Jul}, pages={1239–1251} }
 @article{faircloth_moore_stoufer_kim_jaykus_2021, title={Generation of Nucleic Acid Aptamer Candidates against a Novel Calicivirus Protein Target}, volume={13}, ISSN={["1999-4915"]}, DOI={10.3390/v13091716}, abstractNote={Human norovirus is the leading cause of foodborne illness globally. One of the challenges in detecting noroviruses is the identification of a completely broadly reactive ligand; however, all detection ligands generated to date target the viral capsid, the outermost of which is the most variable region of the genome. The VPg is a protein covalently linked to the viral genome that is necessary for replication but hitherto remains underexplored as a target for detection or therapeutics. The purpose of this work was to generate nucleic acid aptamers against human norovirus (Norwalk) and cultivable surrogate (Tulane) VPgs for future use in detection and therapeutics. Eight rounds of positive-SELEX and two rounds of counter-SELEX were performed. Five and eight unique aptamer sequences were identified for Norwalk and Tulane VPg, respectively, all of which were predicted to be stable (∆G < -5.0) and one of which occurred in both pools. All candidates displayed binding to both Tulane and Norwalk VPg (positive:negative > 5.0), and all but two of the candidates displayed very strong binding (positive:negative > 10.0), significantly higher than binding to the negative control protein (p < 0.05). Overall, this work reports a number of aptamer candidates found to be broadly reactive and specific for in vitro-expressed VPgs across genus that could be used for future application in detection or therapeutics. Future work characterizing binding of the aptamer candidates against native VPgs and in therapeutic applications is needed to further evaluate their application.}, number={9}, journal={VIRUSES-BASEL}, author={Faircloth, Jeremy and Moore, Matthew D. and Stoufer, Sloane and Kim, Minji and Jaykus, Lee-Ann}, year={2021}, month={Sep} }
 @article{brown_chen_siletzky_parsons_jaykus_eifert_ryser_logue_stam_brown_et al._2021, title={Harnessing Whole Genome Sequence Data for Facility-Specific Signatures for Listeria monocytogenes: A Case Study With Turkey Processing Plants in the United States}, volume={5}, ISSN={["2571-581X"]}, url={http://dx.doi.org/10.3389/fsufs.2021.742353}, DOI={10.3389/fsufs.2021.742353}, abstractNote={Listeria monocytogenes is a Gram-positive foodborne pathogen responsible for the severe disease listeriosis and notorious for its ability to persist in food processing plants, leading to contamination of processed, ready-to-eat foods. L. monocytogenes persistence in various food processing environments (FPEs) has been extensively investigated by various subtyping tools, with increasing use of whole genome sequencing (WGS). However, major knowledge gaps remain. There is a need for facility-specific molecular signatures not only for adequate attribution of L. monocytogenes to a specific FPE but also for improved understanding of the ecology and evolution of L. monocytogenes in the food processing ecosystem. Furthermore, multiple strains can be recovered from a single FPE sample, but their diversity can be underestimated with common molecular subtyping tools. In this study we investigated a panel of 54 L. monocytogenes strains from four turkey processing plants in the United States. A combination of WGS and phenotypic assays was employed to assess strain persistence as well as identify facility-specific molecular signatures. Comparative analysis of allelic variation across the whole genome revealed that allelic profiles have the potential to be specific to individual processing plants. Certain allelic profiles remained associated with individual plants even when closely-related strains from other sources were included in the analysis. Furthermore, for certain sequence types (STs) based on the seven-locus multilocus sequence typing scheme, presence and location of premature stop codons in inlA, inlB length, prophage sequences, and the sequence content of a genomic hotspot could serve as plant-specific signatures. Interestingly, the analysis of different isolates from the same environmental sample revealed major differences not only in serotype and ST, but even in the sequence content of strains of the same ST. This study highlights the potential for WGS data to be deployed for identification of facility-specific signatures, thus facilitating the tracking of strain movement through the food chain. Furthermore, deployment of WGS for intra-sample strain analysis allows for a more complete environmental surveillance of L. monocytogenes in food processing facilities, reducing the risk of failing to detect strains that may be clinically relevant and potentially novel.}, journal={FRONTIERS IN SUSTAINABLE FOOD SYSTEMS}, publisher={Frontiers Media SA}, author={Brown, Phillip and Chen, Yi and Siletzky, Robin and Parsons, Cameron and Jaykus, Lee-Ann and Eifert, Joseph and Ryser, Elliot and Logue, Catherine M. and Stam, Christina and Brown, Eric and et al.}, editor={Brown, PhillipEditor}, year={2021}, month={Oct} }
 @article{murphy_scrafford_barraj_bi_higgins_jaykus_tran_2021, title={Potassium chloride-based replacers: modeling effects on sodium and potassium intakes of the US population with cross-sectional data from NHANES 2015-2016 and 2009-2010}, volume={114}, ISSN={["1938-3207"]}, DOI={10.1093/ajcn/nqab020}, abstractNote={Sodium intake in the USA exceeds recommendations. The replacement of added sodium chloride (NaCl) with potassium chloride (KCl) provides a potential strategy to reduce sodium intake. The purpose of this study was to quantitatively estimate changes in intakes of sodium and potassium by the US population assuming use of potassium-based NaCl replacers in top dietary sodium sources. Data collected in the What We Eat in America (WWEIA) component of the 2015–2016 and 2009–2010 NHANES were used to identify top-ranking sources of dietary sodium among the population aged 2 y and older based on contributions from food categories aligning with the FDA draft guidance for voluntary sodium reduction. Predicted nutrient intakes were estimated in models assuming total and feasible and practical (F&P) replacement of added NaCl with KCl in foods and ingredients within the top food sources of sodium. An expert elicitation was conducted to collect information on the F&P KCl replacement of added NaCl. Using 2015–2016 consumption data, the total replacement of added NaCl with KCl in the 18 top-ranking sources of dietary sodium results in a predicted sodium intake of 2004 mg/d from the replacement of 1406 mg/d sodium with 1870 mg/d potassium as KCl. Modeled F&P replacement predicted sodium intakes of 3117 mg/d (range of 2953 to 3255 mg/d) from the replacement of 294 mg/d sodium (155 to 457 mg/d) with 390 mg/d potassium (206 to 608 mg/d). Similar results are seen with 2009–2010 data. The F&P replacement of NaCl with KCl in top-ranking sources of dietary sodium modeled in this study can result in decreased sodium to a level consistent with the short-term intake goal targeted by the FDA of 3000 mg/d, with the mean potassium intake remaining in the range recommended for the apparently healthy population.}, number={1}, journal={AMERICAN JOURNAL OF CLINICAL NUTRITION}, author={Murphy, Mary M. and Scrafford, Carolyn G. and Barraj, Leila M. and Bi, Xiaoyu and Higgins, Kelly A. and Jaykus, Lee-Ann and Tran, Nga L.}, year={2021}, month={Jul}, pages={220–230} }
 @article{burris_simmons_webb_moore_jaykus_zheng_reed_ferreira_brown_bell_2021, title={Salmonella enterica colonization and fitness in pre-harvest cantaloupe production}, volume={93}, ISSN={["1095-9998"]}, DOI={10.1016/j.fm.2020.103612}, abstractNote={Cantaloupes have emerged as significant vehicles of widespread foodborne illness outbreaks caused by bacterial pathogens, including Salmonella . The purpose of this study was to investigate the efficiency of Salmonella colonization and internalization in cantaloupes by relevant routes of contamination. Cantaloupe plants ( Cucumis melo ‘reticulatus’) from two cultivars ‘Athena’ (Eastern) and ‘Primo’ (Western) were grown from commercial seed. Plants were maintained in the NCSU BSL-3P phytotron greenhouse. Salmonella enterica (a cocktail of cantaloupe-associated outbreak serovars Javiana, Newport, Panama, Poona and Typhimurium) contamination was introduced via blossoms or soil at ca. 4.4 log 10 CFU/blossom or 8.4 log 10 CFU/root zone, respectively. Cantaloupes were analyzed for Salmonella by enrichment in accordance with modified FDA-BAM methods. Five randomly chosen colonies from each Salmonella -positive sample were typed using the Agilent 2100 bioanalyzer following multiplex PCR. Data were analyzed for prevalence of contamination and serovar predominance in fruit, stems and soil. Of the total cantaloupe fruit harvested from Salmonella -inoculated blossoms (n = 63), 89% (56/63) were externally contaminated and 73% (46/63) had Salmonella internalized into the fruit. Serovar Panama was the most commonly isolated from the surface of fruit while S. Panama and S. Poona were the most prevalent inside the fruit. When soil was inoculated with Salmonella at one day post-transplant, 13% (8/60) of the plants were shown to translocate the organism to the lower stem (ca. 4 cm) by 7 days post-inoculation (dpi). We observed Salmonella persistence in the soil up to 60 dpi with S. Newport being the predominant serovar at 10 and 20 dpi. These data demonstrate that contaminated soil and blossoms can lead to Salmonella internalization into the plant or fruit at a relatively high frequency. • Salmonella- contaminated soil and blossoms lead to plant or fruit internalization. • Blossom inoculations resulted in a high percentage of Salmonella internalization to fruit. • Serovar Panama was the most commonly isolated serovar from the surface of fruit. • S. Panama and S . Poona were the most prevalent serovars internalized to fruit. • Salmonella persisted in soils up to 60 days post inoculation.}, journal={FOOD MICROBIOLOGY}, author={Burris, Kellie P. and Simmons, Otto D., III and Webb, Hannah M. and Moore, Robin Grant and Jaykus, Lee-Ann and Zheng, Jie and Reed, Elizabeth and Ferreira, Christina M. and Brown, Eric and Bell, Rebecca L.}, year={2021}, month={Feb} }
 @article{perez-garza_franco-frias_garcia-heredia_garcia_leon_jaykus_heredia_2021, title={The Cantaloupe Farm Environment Has a Diverse Genetic Pool of Antibiotic-Resistance and Virulence Genes}, volume={18}, ISSN={["1556-7125"]}, DOI={10.1089/fpd.2020.2900}, abstractNote={Cantaloupes contaminated with pathogens have led to many high-profile outbreaks and illnesses. Since bacterial virulence genes (VGs) can act in tandem with antibiotic-resistance and mobile genetic elements, there is a need to evaluate these gene reservoirs in fresh produce, such as cantaloupes. The goal of this study was to assess the distribution of antibiotic-resistance, virulence, and mobile genetic elements genes (MGEGs) in cantaloupe farm environments. A total of 200 samples from cantaloupe melons (n = 99), farm workers' hands (n = 66), and production water (n = 35) were collected in México. Each sample was assayed for the presence of 14 antibiotic-resistance genes, 15 VGs, and 5 MGEGs by polymerase chain reaction. Our results indicated that tetracycline (tetA and tetB) (18% of cantaloupe, 45% of hand samples) and sulfonamide (sul1) (30% of cantaloupe, 71% of hand samples) resistance genes were frequently detected. The colistin resistance gene (mcr1) was detected in 10% of cantaloupe and 23% of farm workers' hands. Among VGs, Salmonella genes invA and spiA were the most abundant. There was a significantly higher likelihood of detecting antibiotic-resistance, virulence, and MGEGs on hands compared with water samples. These results demonstrate a diverse pool of antibiotic-resistance and VGs in cantaloupe production.}, number={7}, journal={FOODBORNE PATHOGENS AND DISEASE}, author={Perez-Garza, Janeth and Franco-Frias, Eduardo and Garcia-Heredia, Alam and Garcia, Santos and Leon, Juan S. and Jaykus, Lee-Ann and Heredia, Norma}, year={2021}, month={Jul}, pages={469–476} }
 @article{cable_jaykus_hoelzer_newton_torero_2021, title={The impact of COVID-19 on food systems, safety, and security-a symposium report}, volume={1484}, ISSN={["1749-6632"]}, DOI={10.1111/nyas.14482}, abstractNote={Abstract Our food systems depend on complex interactions between farmers and food producers, local and federal governments, and consumers. Underlying these interactions are economic, environmental, and societal factors that can impact the types of food available, access to food, affordability, and food safety. The recent SARS‐CoV‐2 global pandemic has affected multiple aspects of our food systems, from federal governments’ decisions to limit food exports, to the ability of government agencies to inspect food and facilities to the ability of consumers to dine at restaurants. It has also provided opportunities for societies to take a close look at the vulnerabilities in our food systems and reinvent them to be more robust and resilient. For the most part, how these changes ultimately affect the safety and accessibility of food around the world remains to be seen.}, number={1}, journal={ANNALS OF THE NEW YORK ACADEMY OF SCIENCES}, author={Cable, Jennifer and Jaykus, Lee-Ann and Hoelzer, Karin and Newton, John and Torero, Maximo}, year={2021}, month={Jan}, pages={3–8} }
 @article{duong_shumaker_cates_shelley_goodson_bernstein_lavallee_kirchner_goulter_jaykus_et al._2020, title={An Observational Study of Thermometer Use by Consumers When Preparing Ground Turkey Patties}, volume={83}, ISBN={1944-9097}, DOI={10.4315/JFP-19-594}, abstractNote={The purpose of this study was to test the effectiveness of an intervention for consumer thermometer use by using a randomized experimental design and direct observation of meal preparation. The study was conducted in test kitchen facilities in two locations in North Carolina (one urban and one rural). Cameras recorded participants' actions at various locations throughout the kitchen and recorded the meal preparation from beginning to end. Before preparing the meal, a randomized treatment group watched a 3-min U.S. Department of Agriculture (USDA) food safety video “The Importance of Cooking to a Safe Internal Temperature and How to Use a Food Thermometer.” Participants in the control and treatment groups were observed while cooking turkey burgers and preparing a salad to determine whether a thermometer was used to check the doneness of the turkey patties. Following meal preparation, all participants responded to a postobservation interview about food handling behaviors. Treatment group participants were also asked about the intervention. A total of 383 people participated in the study (201 in the control group and 182 in the treatment group). Participants who viewed the video were twice as likely to use a thermometer to check the doneness of the turkey patties compared with the participants who were not exposed to the video (75 versus 34%) and twice as likely to place the thermometer in the correct location (52 versus 23%). Sixty-seven percent of participants who watched the video reported that it influenced their behavior in the kitchen. This study demonstrates the importance of timing and framing of a behavioral intervention for thermometer use and highlights considerations for the development of additional messages (e.g., proper insertion). Participants who viewed a food safety video were twice as likely to use a thermometer. Participants who viewed the video were more likely to place thermometer correctly. Most (67%) of the participants who watched the video said it influenced their behavior.}, number={7}, journal={JOURNAL OF FOOD PROTECTION}, author={Duong, Minh and Shumaker, Ellen Thomas and Cates, Sheryl C. and Shelley, Lisa and Goodson, Lydia and Bernstein, Christopher and Lavallee, Aaron and Kirchner, Margaret and Goulter, Rebecca and Jaykus, Lee-Ann and et al.}, year={2020}, month={Jul}, pages={1167–1174} }
 @article{prince-guerra_nace_lyles_aceituno_bartz_arbogast_gentry-shields_jaykus_heredia_garcia_et al._2020, title={Both Handwashing and an Alcohol-Based Hand Sanitizer Intervention Reduce Soil and Microbial Contamination on Farmworker Hands during Harvest, but Produce Type Matters}, volume={86}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.00780-20}, abstractNote={This study demonstrated that the type of produce commodity handled influences the ability of handwashing with soap and water or a two-step alcohol-based hand sanitizer (ABHS) intervention to reduce soil and bacterial hand contamination. Handwashing with soap and water, as recommended by the FDA’s Produce Safety Rule, when tested in three agricultural environments, does not always reduce bacterial loads. Consistent with past results, we found that the two-step ABHS method performed similarly to handwashing with soap and water but also does not always reduce bacterial loads in these contexts. Given the ease of use of the two-step ABHS method, which may increase compliance, the two-step ABHS method should be further evaluated and possibly considered for implementation in the agricultural environment. Taken together, these results provide important information on hand hygiene effectiveness in three agricultural contexts.}, number={18}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Prince-Guerra, Jessica L. and Nace, Molly E. and Lyles, Robert H. and Aceituno, Anna M. Fabiszewski and Bartz, Faith E. and Arbogast, James W. and Gentry-Shields, Jennifer and Jaykus, Lee-Ann and Heredia, Norma and Garcia, Santos and et al.}, year={2020}, month={Sep} }
 @article{burris_simmons_webb_deese_moore_jaykus_zheng_reed_ferreira_brown_et al._2020, title={Colonization and Internalization of Salmonella enterica and Its Prevalence in Cucumber Plants}, volume={11}, ISSN={1664-302X}, url={http://dx.doi.org/10.3389/fmicb.2020.01135}, DOI={10.3389/fmicb.2020.01135}, abstractNote={Consumption of cucumbers (Cucumis sativus var. sativus) has been linked to several foodborne outbreaks involving Salmonella enterica. The purpose of this work was to investigate the efficiency of colonization and internalization of S. enterica into cucumber plants by various routes of contamination. Produce-associated outbreak strains of Salmonella (a cocktail of serovars Javiana, Montevideo, Newport, Poona and Typhimurium) were introduced to three cultivars of cucumber plants (two slicing cultivars and one pickling) via blossoms (ca. 6.4 log10 CFU/blossom, 4.5 log10 CFU/blossom or 2.5 log10 CFU/blossom) or soil (ca. 8.3 log10 CFU/root zone) and were analyzed for prevalence of Salmonella contamination (internal and external) and serovar predominance in fruit and stems. Of the total slicing fruit harvested from Salmonella-inoculated blossoms (ca. 6.4, 4.5 or 2.5 log10 CFU/blossom), 83.9% (47/56), 81.4% (48/59) or 71.2% (84/118) were found colonized and 67.9% (38/56), 35.6% (21/59) or 22.0% (26/118) had Salmonella internalized into the fruit, respectively. S. Poona was the most prevalent serovar isolated on or in cucumber fruits at all inoculation levels. When soil was inoculated at 1 day post transplant (dpt), 8% (10/120) of the plants were shown to translocate Salmonella to the lower stem 7 days post inoculation (dpi). Results identified blossoms as an important route by which Salmonella internalized at a high percentage into cucumbers, and S. Poona, the same strain isolated from the 2015 outbreak of cucumbers imported from Mexico, was shown to be well adapted to the blossom niche.}, journal={Frontiers in Microbiology}, publisher={Frontiers Media SA}, author={Burris, Kellie P. and Simmons, Otto D. and Webb, Hannah M. and Deese, Lauren M. and Moore, Robin Grant and Jaykus, Lee-Ann and Zheng, Jie and Reed, Elizabeth and Ferreira, Christina M. and Brown, Eric W. and et al.}, year={2020}, month={May} }
 @article{wilson_reynolds_jaykus_escudero-abarca_gerba_2020, title={Comparison of estimated norovirus infection risk reductions for a single fomite contact scenario with residual and nonresidual hand sanitizers}, volume={48}, ISSN={["1527-3296"]}, DOI={10.1016/j.ajic.2019.09.010}, abstractNote={•The residual hand sanitizer out-performed the nonresidual hand sanitizer. •Residual hand sanitizer may reduce infection risk for up to 4 hours. •Longer hand sanitizer contact time translated to higher risk reductions. Background The purpose of this study was to relate experimentally measured log10 human norovirus reductions for a nonresidual (60% ethanol) and a residual (quaternary ammonium-based) hand sanitizer to infection risk reductions. Methods Human norovirus log10 reductions on hands for both sanitizers were experimentally measured using the ASTM International Standard E1838-10 method, with modification. Scenarios included product application to: (1) inoculated fingerpads with 30- and 60-second contact times, and (2) hands followed by inoculation with human norovirus immediately and 4 hours later. Hand sanitizer efficacies were used in a mathematical model estimating norovirus infection risk from a single hand-to-fomite contact under low and high environmental contamination conditions. Results The largest log10 reductions for the residual and nonresidual hand sanitizers were for a 60-second contact time, reducing infection risk by approximately 99% and 85%, respectively. Four hours after application, the residual hand sanitizer reduced infection risks by 78.5% under high contamination conditions, whereas the nonresidual hand sanitizer offered no reduction. Discussion Log10 virus and infection risk reductions were consistently greater for the residual hand sanitizer under all scenarios. Further data describing residual hand sanitizer efficacy with additional contamination or tactile events are needed. Conclusions Residual antinoroviral hand sanitizers may reduce infection risks for up to 4 hours. The purpose of this study was to relate experimentally measured log10 human norovirus reductions for a nonresidual (60% ethanol) and a residual (quaternary ammonium-based) hand sanitizer to infection risk reductions. Human norovirus log10 reductions on hands for both sanitizers were experimentally measured using the ASTM International Standard E1838-10 method, with modification. Scenarios included product application to: (1) inoculated fingerpads with 30- and 60-second contact times, and (2) hands followed by inoculation with human norovirus immediately and 4 hours later. Hand sanitizer efficacies were used in a mathematical model estimating norovirus infection risk from a single hand-to-fomite contact under low and high environmental contamination conditions. The largest log10 reductions for the residual and nonresidual hand sanitizers were for a 60-second contact time, reducing infection risk by approximately 99% and 85%, respectively. Four hours after application, the residual hand sanitizer reduced infection risks by 78.5% under high contamination conditions, whereas the nonresidual hand sanitizer offered no reduction. Log10 virus and infection risk reductions were consistently greater for the residual hand sanitizer under all scenarios. Further data describing residual hand sanitizer efficacy with additional contamination or tactile events are needed. Residual antinoroviral hand sanitizers may reduce infection risks for up to 4 hours.}, number={5}, journal={AMERICAN JOURNAL OF INFECTION CONTROL}, author={Wilson, Amanda M. and Reynolds, Kelly A. and Jaykus, Lee-Ann and Escudero-Abarca, Blanca and Gerba, Charles P.}, year={2020}, month={May}, pages={538–544} }
 @article{escudero-abarca_goulter_arbogast_leslie_green_jaykus_2020, title={Efficacy of alcohol-based hand sanitizers against human norovirus using RNase-RT-qPCR with validation by human intestinal enteroid replication}, volume={71}, ISSN={["1472-765X"]}, DOI={10.1111/lam.13393}, abstractNote={Successful human norovirus (HuNoV) cultivation in stem cell-derived human intestinal enteroids (HIE) was recently reported. The purpose of this study was to evaluate the anti-HuNoV efficacy of two alcohol-based commercial hand sanitizers and 60% ethanol by suspension assay using RNase-RT-qPCR, with subsequent validation of efficacy by HuNoV cultivation using the HIE model. In suspension, when evaluated by RNase-RT-qPCR, 60% ethanol resulted in less than one log10 reduction in HuNoV genome equivalent copies (GEC) regardless of contact time (30 or 60s) or soil load. The two commercial products outperformed 60% ethanol regardless of contact time or soil load, providing 2·2-3·2 log10 HuNoV GEC reductions by suspension assay. Product B could not be validated in the HIE model due to cytotoxicity. Following a 60s exposure, viral replication in the HIE model increased 1·9 ± 0·2 log10 HuNoV GEC for the neutralization (positive) control and increased 0·9 ± 0·2 log10 HuNoV GEC in challenged HIE after treatment with 60% ethanol. No HuNoV replication in HIE was observed after a 60 s exposure to Product A.}, number={6}, journal={LETTERS IN APPLIED MICROBIOLOGY}, author={Escudero-Abarca, B. I. and Goulter, R. M. and Arbogast, J. W. and Leslie, R. A. and Green, K. and Jaykus, L. -A.}, year={2020}, month={Dec}, pages={605–610} }
 @article{tijerina-rodriguez_solis-soto_heredia_leon_jaykus_garcia_2020, title={In-House Validation of a Rinse-Membrane Filtration Method for Processing Fresh Produce Samples for Downstream Cultural Detection of Salmonella, Escherichia coli O157:H7, and Listeria}, volume={83}, ISSN={["1944-9097"]}, DOI={10.4315/JFP-19-581}, abstractNote={More efficient sampling and detection methods of pathogens on fresh produce are needed. The purpose of this study was to compare a novel rinse-membrane filtration method (RMFM) to a more traditional sponge rubbing or stomaching method in processing jalapeño peppers and cantaloupe samples for detection of Escherichia coli, Salmonella enterica, and Listeria monocytogenes. For jalapeño peppers inoculated with 106, 104, and 102 CFU of each pathogen and cantaloupes inoculated at 106 and 104 CFU, all pathogens were detected in all (100%) samples by RMFM at a 10-mL filtration volume, as well as by the stomacher and sponge rubbing methods. However, for cantaloupe inoculated at 102 CFU, detection differed by pathogen: S. enterica (20% RMFM, 60% stomacher, and 20% sponge), L. monocytogenes (40% RMFM, 60% stomacher, and 20% sponge), and E. coli O157:H7 (100% RMFM, 75% stomacher, and 75% sponge). When RMFM was compared with the other methods, in accordance with guidelines in the International Organization for Standardization 16140:2003 protocol, it produced values >95% in relative accuracy, relative specificity, and relative sensitivity. Overall, the RMFM performed similar to or better than the homogenization and sponge surface rubbing methods and is a good alternative for processing large numbers of produce samples for bacterial pathogen detection.}, number={9}, journal={JOURNAL OF FOOD PROTECTION}, author={Tijerina-Rodriguez, Laura E. and Solis-Soto, Luisa and Heredia, Norma and Leon, Juan S. and Jaykus, Lee-Ann and Garcia, Santos}, year={2020}, month={Sep}, pages={1592–1597} }
 @article{andrea corzo-ariyama_garcia-heredia_heredia_garcia_leon_jaykus_solis-soto_2019, title={Phylogroups, pathotypes, biofilm formation and antimicrobial resistance of Escherichia coli isolates in farms and packing facilities of tomato, jalapeno pepper and cantaloupe from Northern Mexico}, volume={290}, ISSN={["1879-3460"]}, DOI={10.1016/j.ijfoodmicro.2018.10.006}, abstractNote={The most commonly used indicator of fecal contamination in fresh produce production and packing is Escherichia coli. In depth analysis of the prevalence and characteristics of naturally occurring E. coli strains in these environments is important because it can (1) serve as an indicator of sources of fecal contamination; and (2) provide information on strain pathogenicity, persistence, and other defining characteristics such as multidrug resistance. In this study, we analyzed 341 E. coli strains isolated from the jalapeño pepper, tomato and cantaloupe farm environments, in Northeast Mexico. Strains were isolated from produce, farmworkers' hands, soil and water. Pathotypes, genotypes, biofilm formation and antibiotic resistance were characterized. Phylogenetic subgroups and identification of diarrheagenic E. coli were determined by PCR; biofilm formation was quantified using a plate-based colorimetric method. Antibiotic resistance was analyzed by the Kirby Bauer diffusion disc method. Most isolates (N = 293, 86%) belonged to phylogenetic group A. Only four isolates (1.2%) were diarrheagenic: EPEC (N = 3) and ETEC (N = 1). Antibiotic resistance to tetracycline (23.2%) and ampicillin (19.9%) was high, and only 3.5% of the strains presented resistance to >5 antibiotics. Biofilms were produced by most strains (76%), among which 34.4% were categorized as high producers. The presence of antibiotic resistant E. coli strains that may contain gene markers for pathogenicity and which can form biofilms suggests potential health risks for consumers.}, journal={INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY}, author={Andrea Corzo-Ariyama, Hesperia and Garcia-Heredia, Alam and Heredia, Norma and Garcia, Santos and Leon, Juan and Jaykus, LeeAnn and Solis-Soto, Luisa}, year={2019}, month={Feb}, pages={96–104} }
 @book{allison_brown_goddard_guerinot_jansson_jaykus_jensen_khosla_lougee_lowry_et al._2019, title={Science Breakthroughs to Advance Food and Agricultural Research by 2030}, DOI={10.17226/25059}, journal={SCIENCE BREAKTHROUGHS TO ADVANCE FOOD AND AGRICULTURAL RESEARCH BY 2030}, author={Allison, David B. and Brown, Corrie C. and Goddard, Lisa M. and Guerinot, Mary Lou and Jansson, Janet K. and Jaykus, Lee-Ann and Jensen, Helen H. and Khosla, Rajiv and Lougee, Robin and Lowry, Gregory V. and et al.}, year={2019}, pages={1–228} }
 @misc{clayton_bolinger_jaykus_2018, title={Disinfectant testing against human norovirus surrogates-What infection preventionists need to know}, volume={39}, ISSN={["1559-6834"]}, DOI={10.1017/ice.2018.210}, number={11}, journal={INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY}, author={Clayton, James S. and Bolinger, Hannah K. and Jaykus, Lee-Ann}, year={2018}, month={Nov}, pages={1388–1389} }
 @article{manuel_moore_jaykus_2018, title={Predicting human norovirus infectivity - Recent advances and continued challenges}, volume={76}, ISSN={0740-0020}, url={http://dx.doi.org/10.1016/J.FM.2018.06.015}, DOI={10.1016/J.FM.2018.06.015}, abstractNote={Human norovirus is the leading cause of foodborne illness globally, imposing a considerable public health and economic burden. Historically, one of the major obstacles to the study of human noroviruses has been the lack of an in vitro cultivation system. In addition to hindering elucidation of viral pathogenesis, research efforts have been limited by the inability to discriminate infectious from non-infectious viral particles. Two recent breakthrough human norovirus in vitro cultivation system systems have been reported, but in their current state, may be unsuitable for routine detection or study of human noroviruses in the food and water sciences. More accessible alternative techniques utilizing molecular assays, animal models, and surrogate virus systems for prediction of human norovirus infectivity have been presented. The purpose of this review is to present the multiple recent techniques used to assess human norovirus infectivity, including recently described human norovirus in vitro cultivation systems, cultivable surrogate viruses, animal models, and alternative molecular techniques, and discuss their advantages and disadvantages in the context of determining human norovirus infectivity.}, journal={Food Microbiology}, publisher={Elsevier BV}, author={Manuel, Clyde S. and Moore, Matthew D. and Jaykus, Lee-Ann}, year={2018}, month={Dec}, pages={337–345} }
 @article{suh_choi_dwivedi_moore_escudero-abarca_jaykus_2018, title={Use of DNA aptamer for sandwich type detection of Listeria monocytogenes}, volume={557}, DOI={10.1016/j.ab.2018.04.009}, abstractNote={A single stranded (ss) DNA aptamer, specific to members of Listeria genus, was used to develop a two-site binding sandwich assay for capture and detection of L. monocytogenes. Antibody-immobilized immunomagnetic beads were used to capture L. monocytogenes, followed by their exposure to the aptamer detector. Detection was achieved by amplification of cell-bound aptamers by qPCR. The lower limit of detection for the combined assay was 2.5 CFU L. monocytogenes in 500 μl buffer. This is juxtaposed to a detection limit of 2.4 log10 CFU in 500 μl buffer for immunomagnetic separation coupled with qPCR detection of L. monocytogenes targeting the hly gene. When applied to turkey deli meat, subjected to 24 h of non-selective enrichment, the two-site binding sandwich assay showed positive results at initial inoculum levels of 1-2 log10 CFU per 25 g sample. Because of its lower limit of detection, the assay reported here could be useful for detection of L. monocytogenes in foods and environmental samples.}, journal={ANALYTICAL BIOCHEMISTRY}, author={Suh, Soo Hwan and Choi, Soo Jung and Dwivedi, Hari P. and Moore, Matthew D. and Escudero-Abarca, Blanca I and Jaykus, Lee-Ann}, year={2018}, pages={27–33} }
 @misc{moore_jaykus_2018, title={Virus-Bacteria Interactions: Implications and Potential for the Applied and Agricultural Sciences}, volume={10}, ISSN={["1999-4915"]}, DOI={10.3390/v10020061}, abstractNote={Eukaryotic virus-bacteria interactions have recently become an emerging topic of study due to multiple significant examples related to human pathogens of clinical interest. However, such omnipresent and likely important interactions for viruses and bacteria relevant to the applied and agricultural sciences have not been reviewed or compiled. The fundamental basis of this review is that these interactions have importance and deserve more investigation, as numerous potential consequences and applications arising from their discovery are relevant to the applied sciences. The purpose of this review is to highlight and summarize eukaryotic virus-bacteria findings in the food/water, horticultural, and animal sciences. In many cases in the agricultural sciences, mechanistic understandings of the effects of virus-bacteria interactions remain unstudied, and many studies solely focus on co-infections of bacterial and viral pathogens. Given recent findings relative to human viral pathogens, further research related to virus-bacteria interactions would likely result in numerous discoveries and beneficial applications.}, number={2}, journal={VIRUSES-BASEL}, author={Moore, Matthew D. and Jaykus, Lee-Ann}, year={2018}, month={Feb} }
 @misc{overbey_jaykus_chapman_2017, title={A Systematic Review of the Use of Social Media for Food Safety Risk Communication}, volume={80}, ISSN={["1944-9097"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85027976727&partnerID=MN8TOARS}, DOI={10.4315/0362-028x.jfp-16-345}, abstractNote={This article covers the current published literature related to the use of social media in food safety and infectious disease communication. The aim was to analyze literature recommendations and draw conclusions about how best to utilize social media for food safety risk communication going forward. A systematic literature review was conducted, and 24 articles were included for analysis. The inclusion criteria were (i) original peer-reviewed articles and (ii) primary focus on communication through social media about food safety and/or infectious diseases. Studies were coded for themes about social media applications, benefits, limitations, and best practices. Trust and personal beliefs were important drivers of social media use. The wide reach, immediacy, and information gathering capacities of social media were frequently cited benefits. Suggestions for social media best practices were inconsistent among studies, and study designs were highly variable. More evidence-based suggestions are needed to better establish guidelines for social media use in food safety and infectious disease risk communication. The information gleaned from this review can be used to create effective messages for shaping food safety behaviors.}, number={9}, journal={JOURNAL OF FOOD PROTECTION}, author={Overbey, Katie N. and Jaykus, Lee-Ann and Chapman, Benjamin J.}, year={2017}, month={Sep}, pages={1537–1549} }
 @article{moore_jaykus_2017, title={A plate-based histo-blood group antigen binding assay for evaluation of human norovirus receptor binding ability}, volume={533}, ISSN={["1096-0309"]}, DOI={10.1016/j.ab.2017.06.012}, abstractNote={Human norovirus is a leading cause of gastroenteritis worldwide. Although two in vitro cultivation methods have been reported, they cannot provide mechanistic insights into viral inactivation. Receptor-binding assays supplement these assays and give insight into capsid integrity. We present a streamlined version of a receptor-binding assay with minimal time-to-result while maintaining accuracy and high throughput. We validate assay performance for physical and chemical inactivation treatments of a norovirus GII.4 capsid. The assay produces a high positive/negative ratio (25.3 ± 4.9) in <2.5 h and has a limit of detection of 0.1 μg/ml capsid. This method is a valuable additional tool for understanding human norovirus inactivation.}, journal={ANALYTICAL BIOCHEMISTRY}, author={Moore, Matthew D. and Jaykus, Lee-Ann}, year={2017}, month={Sep}, pages={56–59} }
 @article{bartz_lickness_heredia_aceituno_newman_hodge_jaykus_garcia_leon_2017, title={Contamination of Fresh Produce by Microbial Indicators on Farms and in Packing Facilities: Elucidation of Environmental Routes}, volume={83}, ISSN={["1098-5336"]}, DOI={10.1128/aem.02984-16}, abstractNote={ABSTRACT To improve food safety on farms, it is critical to quantify the impact of environmental microbial contamination sources on fresh produce. However, studies are hampered by difficulties achieving study designs with powered sample sizes to elucidate relationships between environmental and produce contamination. Our goal was to quantify, in the agricultural production environment, the relationship between microbial contamination on hands, soil, and water and contamination on fresh produce. In 11 farms and packing facilities in northern Mexico, we applied a matched study design: composite samples ( n = 636, equivalent to 11,046 units) of produce rinses were matched to water, soil, and worker hand rinses during two growing seasons. Microbial indicators (coliforms, Escherichia coli , Enterococcus spp., and somatic coliphage) were quantified from composite samples. Statistical measures of association and correlations were calculated through Spearman's correlation, linear regression, and logistic regression models. The concentrations of all microbial indicators were positively correlated between produce and hands (ρ range, 0.41 to 0.75; P < 0.01). When E. coli was present on hands, the handled produce was nine times more likely to contain E. coli ( P < 0.05). Similarly, when coliphage was present on hands, the handled produce was eight times more likely to contain coliphage ( P < 0.05). There were relatively low concentrations of indicators in soil and water samples, and a few sporadic significant associations were observed between contamination of soil and water and contamination of produce. This methodology provides a foundation for future field studies, and results highlight the need for interventions surrounding farmworker hygiene and sanitation to reduce microbial contamination of farmworkers' hands. IMPORTANCE This study of the relationships between microbes on produce and in the farm environment can be used to support the design of targeted interventions to prevent or reduce microbial contamination of fresh produce with associated reductions in foodborne illness.}, number={11}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Bartz, Faith E. and Lickness, Jacquelyn Sunshine and Heredia, Norma and Aceituno, Anna Fabiszewski and Newman, Kira L. and Hodge, Domonique Watson and Jaykus, Lee-Ann and Garcia, Santos and Leon, Juan S.}, year={2017}, month={Jun} }
 @article{moore_jaykus_2017, title={Development of a Recombinase Polymerase Amplification Assay for Detection of Epidemic Human Noroviruses}, volume={7}, ISSN={["2045-2322"]}, DOI={10.1038/srep40244}, abstractNote={Abstract Human norovirus is a leading cause of viral gastroenteritis worldwide. Rapid detection could facilitate control, however widespread point-of-care testing is infrequently done due to the lack of robust and portable methods. Recombinase polymerase amplification (RPA) is a novel isothermal method which rapidly amplifies and detects nucleic acids using a simple device in near real-time. An RT-RPA assay targeting a recent epidemic human norovirus strain (GII.4 New Orleans) was developed and evaluated in this study. The assay successfully detected purified norovirus RNA from multiple patient outbreak isolates and had a limit of detection of 3.40 ± 0.20 log 10 genomic copies (LGC), which is comparable to most other reported isothermal norovirus amplification methods. The assay also detected norovirus in directly boiled stool, and displayed better resistance to inhibitors than a commonly used RT-qPCR assay. The assay was specific, as it did not amplify genomes from 9 non-related enteric viruses and bacteria. The assay detected norovirus in some samples in as little as 6 min, and the entire detection process can be performed in less than 30 min. The reported RT-RPA method shows promise for sensitive point-of-care detection of epidemic human norovirus, and is the fastest human norovirus amplification method to date.}, journal={SCIENTIFIC REPORTS}, author={Moore, Matthew D. and Jaykus, Lee-Ann}, year={2017}, month={Jan} }
 @article{moorman_montazeri_jaykus_2017, title={Efficacy of Neutral Electrolyzed Water for Inactivation of Human Norovirus}, volume={83}, ISSN={["1098-5336"]}, DOI={10.1128/aem.00653-17}, abstractNote={ABSTRACT Human norovirus (NoV) is the leading cause of acute gastroenteritis worldwide. Persistence on surfaces and resistance to many conventional disinfectants contribute to widespread transmission of norovirus. We examined the efficacy of neutral electrolyzed water (NEW; pH 7) for inactivation of human NoV GII.4 Sydney in suspension (ASTM method 1052-11) and on stainless steel surfaces (ASTM method 1053-11) with and without an additional soil load. The impact of the disinfectant on viral capsid was assessed using reverse transcriptase quantitative PCR (RT-qPCR; with an RNase pretreatment), SDS-PAGE, transmission electron microscopy, and a histo-blood group antigen (HBGA) receptor-binding assay. These studies were done in parallel with those using Tulane virus (TuV), a cultivable human NoV surrogate. Neutral electrolyzed water at 250 ppm free available chlorine produced a 4.8- and 0.4-log 10 reduction in NoV genome copy number after 1 min in suspension and on stainless steel, respectively. Increasing the contact time on surfaces to 5, 10, 15, and 30 min reduced human NoV genomic copies by 0.5, 1.6, 2.4, and 5.0 log 10 and TuV infectious titers by 2.4, 3.0, 3.8, and 4.1 log 10 PFU, respectively. Increased soil load effectively eliminated antiviral efficacy regardless of testing method and virus. Exposure to NEW induced a near complete loss of receptor binding (5 ppm, 30 s), degradation of VP1 major capsid protein (250 ppm, 5 min), and increased virus particle aggregation (150 ppm, 30 min). Neutral electrolyzed water at 250 ppm shows promise as an antinoroviral disinfectant when used on precleaned stainless steel surfaces. IMPORTANCE Norovirus is the leading cause of acute viral gastroenteritis worldwide. Transmission occurs by fecal-oral or vomitus-oral routes. The persistence of norovirus on contaminated environmental surfaces exacerbates its spread, as does its resistance to many conventional disinfectants. The purpose of this research was to evaluate the antinoroviral efficacy of neutral electrolyzed water (NEW), a novel chlorine-based disinfectant that can be used at reduced concentrations, making it more environmentally friendly and less corrosive than bleach. An industrial-scale electrochemical activation device capable of producing relatively stable electrolyzed water at a wide pH range was used in this study. Experiments showed that 250 ppm NEW effectively eliminated (defined as a 5-log 10 reduction) human norovirus GII.4 Sydney (epidemic strain) on clean stainless steel surfaces after a 30-min exposure. Supporting studies showed that, like bleach, NEW causes inactivation by disrupting the virus capsid. This product shows promise as a bleach alternative with antinoroviral efficacy.}, number={16}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Moorman, Eric and Montazeri, Naim and Jaykus, Lee-Ann}, year={2017}, month={Aug} }
 @article{manuel_moore_jaykus_2017, title={Efficacy of a disinfectant containing silver dihydrogen citrate against GI.6 and GII.4 human norovirus}, volume={122}, ISSN={["1365-2672"]}, DOI={10.1111/jam.13331}, abstractNote={Human norovirus is a major public health burden and is resistant to numerous sanitizers and disinfectants. In this study, we tested the efficacy of an antimicrobial product containing a blend of silver ions and citric acid (silver dihydrogen citrate; SDC) against GI.6 and GII.4 HuNoV. Pure® hard surface disinfectant (Pure Bioscience, El Cajon, CA) was evaluated using ASTM International virucidal suspension and stainless steel carrier assays. The effect of SDC (or citrate alone) exposure on viral integrity was evaluated using RT‐qPCR, transmission electron microscopy, sodium dodecyl sulphate‐polyacrylamide gel electrophoresis/Western blot analysis and a receptor‐binding assay. Suspension assays showed a 4·0 log10 reduction in RNA copy number within 5 min, while carrier assays showed a 2·0–3·0 log10 reduction in 30 min. Incorporating a simulated soil load into the sample matrix significantly reduced product efficacy. Treated particles displayed deformation and aggregation, a 50% reduction in viral capsid protein band intensity, and an 80% reduction in histo‐blood group antigen receptor‐binding ability. Our results suggest that SDC acts exclusively on the viral capsid, and shows efficacy against HuNoV when used on precleaned surfaces. This study sheds light on the mechanisms and efficacy of a novel antimicrobial against HuNoV. Our results suggest: (i) silver ions exclusively target the viral capsid, and not the RNA genome; (ii) citrate is not crucial for HuNoV capsid deformation.}, number={1}, journal={JOURNAL OF APPLIED MICROBIOLOGY}, author={Manuel, C. S. and Moore, M. D. and Jaykus, L. -A.}, year={2017}, month={Jan}, pages={78–86} }
 @article{tung-thompson_escudero-abarca_outlaw_ganee_cassard_mabilat_jaykus_2017, title={Evaluation of a Surface Sampling Method for Recovery of Human Noroviruses Prior to Detection Using Reverse Transcription Quantitative PCR}, volume={80}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x.jfp-16-276}, abstractNote={Human noroviruses are the most common cause of acute viral gastroenteritis, and the environmental persistence of these viruses contributes to their transmissibility. Environmental sampling is thus an important tool for investigating norovirus outbreaks and for assessing the effectiveness of cleaning and decontamination regimens. The purpose of this study was to evaluate a sampling material (wipes) for their efficacy at recovering human norovirus from hard surfaces and foods. Dilutions of a human norovirus GII.4 stool specimen derived from an outbreak were applied to hard surfaces (stainless steel and ceramic) and the surfaces of representative foods (green pepper, apple, tomato, and cheese). The viruses were recovered at various times postinoculation using the wipes, followed by RNA extraction and reverse transcription quantitative PCR. Recovery efficiency ranged from 74% to almost 100% for all artificially inoculated hard surfaces and for most fresh produce surfaces. Less efficient recovery was observed for cheese. Viral RNA could be recovered from select surfaces for up to 7 days postinoculation, with a <1 log reduction in genome copy number. In field tests, 24 (11%) of 210 environmental samples collected during winter 2012 from restrooms in North Carolina were presumptively positive for human norovirus, and six of these samples were confirmed as GII.4 by sequencing. These wipes may be a valuable tool for investigations of norovirus outbreaks and studies of norovirus prevalence.}, number={2}, journal={JOURNAL OF FOOD PROTECTION}, author={Tung-Thompson, Grace and Escudero-Abarca, Blanca I. and Outlaw, Janie and Ganee, Arnaud and Cassard, Sylvanie and Mabilat, Claude and Jaykus, Lee-Ann}, year={2017}, month={Feb}, pages={231–236} }
 @article{almand_moore_outlaw_jaykus_2017, title={Human norovirus binding to select bacteria representative of the human gut microbiota}, volume={12}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0173124}, abstractNote={Recent reports describe the ability of select bacterial strains to bind human norovirus, although the specificity of such interactions is unknown. The purpose of this work was to determine if a select group of bacterial species representative of human gut microbiota bind to human norovirus, and if so, to characterize the intensity and location of that binding. The bacteria screened included naturally occurring strains isolated from human stool (Klebsiella spp., Citrobacter spp., Bacillus spp., Enterococcus faecium and Hafnia alvei) and select reference strains (Staphylococcus aureus and Enterobacter cloacae). Binding in PBS was evaluated to three human norovirus strains (GII.4 New Orleans 2009 and Sydney 2012, GI.6) and two surrogate viruses (Tulane virus and Turnip Crinkle Virus (TCV)) using a suspension assay format linked to RT-qPCR for quantification. The impact of different overnight culture media prior to washing on binding efficiency in PBS was also evaluated, and binding was visualized using transmission electron microscopy. All bacteria tested bound the representative human norovirus strains with high efficiency (<1 log10 of input virus remained unbound or <10% unbound and >90% binding efficiency) (p>0.05); there was selective binding for Tulane virus and no binding observed for TCV. Binding efficiency was highest when bacteria were cultured in minimal media (<1 log10 of input virus remained unbound, so >90% bound), but notably decreased when cultured in enriched media (1–3 log10 unbound or 0.01 –<90% bound)) (p<0.05). The norovirus-bacteria binding occurred around the outer cell surfaces and pili structures, without apparent localization. The findings reported here further elucidate and inform the dynamics between human noroviruses and enteric bacteria with implications for norovirus pathogenesis.}, number={3}, journal={PLOS ONE}, author={Almand, Erin A. and Moore, Matthew D. and Outlaw, Janie and Jaykus, Lee-Ann}, year={2017}, month={Mar} }
 @article{jaykus_2017, title={Keys to successful grant writing}, volume={82}, number={7}, journal={Journal of Food Science}, author={Jaykus, L. A.}, year={2017}, pages={1511–1512} }
 @article{newman_bartz_johnston_moe_jaykus_leon_2017, title={Microbial Load of Fresh Produce and Paired Equipment Surfaces in Packing Facilities Near the US and Mexico Border}, volume={80}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x.jfp-16-365}, abstractNote={Several produce-associated outbreaks have been linked to the packing facility. Equipment surfaces may be an important source of contamination. The goal was to assess whether the microbial load of packing facility surfaces is associated with the microbial load of produce. From November 2000 to December 2003, 487 matched produce (14 types) and equipment surfaces (six production steps) were sampled from eight packing facilities in the United States near the border with Mexico and enumerated for aerobic plate counts (APC), Escherichia coli , Enterococcus, and coliforms. Bivariate correlations were assessed by Spearman's ρ, and adjusted associations were assessed by multilevel mixed linear regression models. In general, the microbial load both increased and decreased on produce (0.2 to 1.0 log CFU/g) and equipment surfaces (0.5 to 3.0 log CFU/cm2) across production steps. Equipment surface and produce microbial loads were correlated, but correlations varied from none to high depending on the equipment surface. For example, significant correlations (P < 0.01) included APC (ρ = 0.386) and Enterococcus (ρ = 0.562) with the harvest bin, E. coli (ρ = 0.372) and Enterococcus (ρ = 0.355) with the merry-go-round, Enterococcus (ρ = 0.679) with rinse cycle equipment, APC (ρ = 0.542) with the conveyer belt, and for all indicators with the packing box (ρ = 0.310 to 0.657). After controlling for crop type, sample replicate group, and sample location, there were significant positive associations between the log concentration of Enterococcus on produce and the harvest bin (β = 0.259, P < 0.01) and the rinse cycle (β = 0.010, P = 0.01), and between the log concentration of all indicators on produce and the packing box (β = 0.155 to 0.500, all P < 0.01). These statistically significant associations between microbial loads on packing facility surfaces and fresh produce confirm the importance of packing facility sanitation to protect produce quality and safety.}, number={4}, journal={JOURNAL OF FOOD PROTECTION}, author={Newman, Kira L. and Bartz, Faith E. and Johnston, Lynette and Moe, Christine L. and Jaykus, Lee-Ann and Leon, Juan S.}, year={2017}, month={Apr}, pages={582–589} }
 @misc{almand_moore_jaykus_2017, title={Norovirus Binding to Ligands Beyond Histo-Blood Group Antigens}, volume={8}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2017.02549}, abstractNote={Histo-blood group antigens (HBGAs) are commonly accepted as the cellular receptors for human norovirus. However, some human noroviruses have been found not to bind any HBGA ligand, suggesting potential additional co-factors. Some ligands have been found to bind noroviruses and have the potential to be additional cellular receptors/attachment factors for human norovirus or inhibitors of the HBGA interaction. The studies identifying these largely characterize different chemical, human, food or bacterial components and their effect on norovirus binding and infection, although the mechanism of interaction is unknown in many cases. This review seeks to supplement the already well-covered HBGA-norovirus literature by covering non-HBGA human norovirus ligands and inhibitors to provide investigators with a more comprehensive view of norovirus ligands.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Almand, Erin A. and Moore, Matthew D. and Jaykus, Lee-Ann}, year={2017}, month={Dec} }
 @article{moore_jaykus_2017, title={Recombinase polymerase amplification: a promising point-of-care detection method for enteric viruses}, volume={12}, ISSN={["1746-0808"]}, DOI={10.2217/fvl-2017-0034}, abstractNote={Viral enteric disease imposes a considerable public health and economic burden globally in both humans and livestock. Because enteric viruses are highly transmissible and resistant to numerous control strategies, making early in-field or point-of-care detection is important. There are problems with ligand-based detection strategies (e.g., sensitivity, false positive/negatives) for virus detection. Traditional amplification-based strategies are sensitive, but not as portable or rapid. Recombinase polymerase amplification is a new isothermal technique that utilizes bacterial genome repair enzymes to rapidly amplify target sequences. This report reviews the use of recombinase polymerase amplification for virus detection, showing that the method has favorable fundamental properties supporting its promise for rapid point-of-care detection of enteric viruses.}, number={8}, journal={FUTURE VIROLOGY}, author={Moore, Matthew D. and Jaykus, Lee-Ann}, year={2017}, month={Aug}, pages={421–429} }
 @misc{wang_lapinski_quilliam_jaykus_fraser_2017, title={The effect of hand-hygiene interventions on infectious disease-associated absenteeism in elementary schools: A systematic literature review}, volume={45}, ISSN={["1527-3296"]}, DOI={10.1016/j.ajic.2017.01.018}, abstractNote={Background Hand-hygiene interventions are widely used in schools but their effect on reducing absenteeism is not well known. Methods The aim of our literature review was to determine whether implementation of a hand-hygiene intervention reduced infectious disease-associated absenteeism in elementary schools. The eligible studies (N = 19), published between 1996 and 2014, were summarized and the methodologic quality of each was assessed. Results Our review indicated evidence is available to show hand-hygiene interventions had an effect on reducing acute gastrointestinal illness-associated absenteeism but inadequate evidence is available to show an effect on respiratory illness-associated absenteeism. Conclusions The methodologic quality assessment of eligible studies revealed common design flaws, such as lack of randomization, blinding, and attrition, which must be addressed in future studies to strengthen the evidence base on the effect of hand-hygiene interventions on school absenteeism. Hand-hygiene interventions are widely used in schools but their effect on reducing absenteeism is not well known. The aim of our literature review was to determine whether implementation of a hand-hygiene intervention reduced infectious disease-associated absenteeism in elementary schools. The eligible studies (N = 19), published between 1996 and 2014, were summarized and the methodologic quality of each was assessed. Our review indicated evidence is available to show hand-hygiene interventions had an effect on reducing acute gastrointestinal illness-associated absenteeism but inadequate evidence is available to show an effect on respiratory illness-associated absenteeism. The methodologic quality assessment of eligible studies revealed common design flaws, such as lack of randomization, blinding, and attrition, which must be addressed in future studies to strengthen the evidence base on the effect of hand-hygiene interventions on school absenteeism.}, number={6}, journal={AMERICAN JOURNAL OF INFECTION CONTROL}, author={Wang, Zhangqi and Lapinski, Maria and Quilliam, Elizabeth and Jaykus, Lee-Ann and Fraser, Angela}, year={2017}, month={Jun}, pages={682–689} }
 @article{montazeri_manuel_moorman_khatiwada_williams_jaykus_2017, title={Virucidal Activity of Fogged Chlorine Dioxide-and Hydrogen Peroxide-Based Disinfectants against Human Norovirus and Its Surrogate, Feline Calicivirus, on Hard-to-Reach Surfaces}, volume={8}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2017.01031}, abstractNote={Human norovirus (NoV) is the leading cause of foodborne illnesses in the United States. Norovirus is shed in high numbers in the feces and vomitous of infected individuals. Contact surfaces contaminated with bodily fluids harboring infectious virus particles serve as vehicles for pathogen transmission. Environmental stability of NoV and its resistance to many conventional disinfectants necessitate effective inactivation strategies to control the spread of virus. We investigated the efficacy of two commercial disinfectants, hydrogen peroxide (7.5%) and a chlorine dioxide (0.2%)-surfactant-based product using a fogging delivery system against human NoV GI.6 and GII.4 Sydney strains as well as the cultivable surrogate, feline calicivirus (FCV) dried on stainless steel coupons. Log10 reductions in human NoV and FCV were calculated utilizing RNase RT-qPCR and infectivity (plaque) assay, respectively. An improved antiviral activity of hydrogen peroxide as a function of disinfectant formulation concentration in the atmosphere was observed against both GII.4 and FCV. At 12.4 ml/m3, hydrogen peroxide achieved a respective 2.5±0.1 and 2.7±0.3 log10 reduction in GI.6 and GII.4 NoV genome copies, and a 4.3±0.1 log10 reduction in infectious FCV within 5 min. At the same disinfectant formulation concentration, chlorine dioxide-surfactant-based product resulted in a respective 1.7±0.2, 0.6±0.0 and 2.4±0.2 log10 reduction in GI.6, GII.4 and FCV within 10 min; however, increasing the disinfectant formulation concentration to 15.9 ml/m3 negatively impacted its efficacy. Fogging uniformly delivered the disinfectants throughout the room, and effectively decontaminated viruses on hard-to-reach surfaces. Hydrogen peroxide delivered by fog showed promising virucidal activity against FCV by meeting the U.S. EPA 4-log10 reduction criteria for an anti-noroviral disinfectant; however, fogged chlorine dioxide-surfactant-based product did not achieve a 4-log10 inactivation. Future investigation aimed at optimizing decontamination practices is warranted.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Montazeri, Naim and Manuel, Clyde and Moorman, Eric and Khatiwada, Janak R. and Williams, Leonard L. and Jaykus, Lee-Ann}, year={2017}, month={Jun} }
 @misc{almand_moore_jaykus_2017, title={Virus-bacteria interactions: An emerging topic in human infection}, volume={9}, number={3}, journal={Viruses-Basel}, author={Almand, E. A. and Moore, M. D. and Jaykus, L. A.}, year={2017} }
 @misc{knight_haines_stals_li_uyttendaele_knight_jaykus_2016, title={A systematic review of human norovirus survival reveals a greater persistence of human norovirus RT-qPCR signals compared to those of cultivable surrogate viruses}, volume={216}, ISSN={["1879-3460"]}, DOI={10.1016/j.ijfoodmicro.2015.08.015}, abstractNote={Human noroviruses (hNoV) are the single largest cause of acute gastroenteritis in the western world. The efficacy of hNoV control measures remains largely unknown, partly owing to the inability to grow the virus in vitro and partly to the large number of surrogate studies of unknown relevance. A systematic review of the persistence and survival of hNoV in foods and the environment was undertaken based upon PRISMA (preferred reporting items for systematic reviews and meta analyses) guidelines to answer the questions: (1) “What are the natural hNoV persistence characteristics in food and the environment?” and (2) “How can these properties be altered by applying physical and/or chemical treatments to foods or food contact surfaces?” Over 10,000 citations were screened using defined inclusion and exclusion criteria. One hundred and twenty-six (126) citations were identified for further evaluation and data were extracted based upon the conditions of study and treatment (e.g., treatment parameters, pH, and temperature, time, infectivity, and RT-qPCR results). Since the only markers for hNoV persistence and survival were RT-qPCR data and human challenge studies, citations for further analysis were restricted to only those that included data on hNoV behavior (using RT-qPCR) as compared directly to surrogate virus behavior (using both RT-qPCR and infectivity) in the same study, and clinical studies. Based on these criteria, a total of 12 independent studies (5 for thermal inactivation and 7 for available chlorine) and 3 human challenge studies were identified. RT-qPCR always underestimated reductions in surrogate virus titre as a function of treatment when compared to infectivity. The corresponding reductions in RT-qPCR signals for hNoV under comparable conditions were nearly always less than those observed for the surrogates. These relationships were statistically significant for heat when comparing persistence of hNoV RT-qPCR signals with surrogate MNV-1 RT-qPCR signals (P equal persistence = < 0.07); and for free chlorine when comparing persistence of hNoV RT-qPCR signals to those of FCV F-9 (p = < 0.01). Overall the data suggest that hNoV are frequently more resistant to typical food and environmental control measures compared with cultivable surrogate viruses, when basing data on comparative RT-qPCR results.}, journal={INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY}, author={Knight, Angus and Haines, John and Stals, Arnbroos and Li, Dan and Uyttendaele, Mieke and Knight, Alastair and Jaykus, Lee-Ann}, year={2016}, month={Jan}, pages={40–49} }
 @article{thomas_binder_mclaughlin_jaykus_hanson_powell_chapman_2016, title={Assessment of Risk Communication about Undercooked Hamburgers by Restaurant Servers}, volume={79}, ISSN={["1944-9097"]}, url={https://publons.com/publon/21063768/}, DOI={10.4315/0362-028x.jfp-16-065}, abstractNote={According to the U.S. Food and Drug Administration 2013 Model Food Code, it is the duty of a food establishment to disclose and remind consumers of risk when ordering undercooked food such as ground beef. The purpose of this study was to explore actual risk communication behaviors of food establishment servers. Secret shoppers visited 265 restaurants in seven geographic locations across the United States, ordered medium rare burgers, and collected and coded risk information from chain and independent restaurant menus and from server responses. The majority of servers reported an unreliable method of doneness (77%) or other incorrect information (66%) related to burger doneness and safety. These results indicate major gaps in server knowledge and risk communication, and the current risk communication language in the Model Food Code does not sufficiently fill these gaps. The question is "should servers even be acting as risk communicators?" There are numerous challenges associated with this practice, including high turnover rates, limited education, and the high stress environment based on pleasing a customer. If servers are designated as risk communicators, food establishment staff should be adequately trained and provided with consumer advisory messages that are accurate, audience appropriate, and delivered in a professional manner so that customers can make informed food safety decisions.}, number={12}, journal={JOURNAL OF FOOD PROTECTION}, author={Thomas, Ellen M. and Binder, Andrew R. and Mclaughlin, Anne and Jaykus, Lee-Ann and Hanson, Dana and Powell, Douglas and Chapman, Benjamin}, year={2016}, month={Dec}, pages={2113–2118} }
 @article{almand_goulter_jaykus_2016, title={Capture and concentration of viral and bacterial foodborne pathogens using apolipoprotein H}, volume={128}, ISSN={["1872-8359"]}, DOI={10.1016/j.mimet.2016.07.014}, abstractNote={The need for improved pathogen separation and concentration methods to reduce time-to-detection for foodborne pathogens is well recognized. Apolipoprotein H (ApoH) is an acute phase human plasma protein that has been previously shown to interact with viruses, lipopolysaccharides (LPS) and bacterial proteins. The purpose of this study was to determine if ApoH was capable of binding and efficiently capturing two representative human norovirus strains (GI.1 and GII.4), a cultivable surrogate, and four bacterial pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica serovar Enteritidis, and Staphylococcus aureus). Experiments were carried out using an ApoH-conjugated magnetic bead-based capture followed by pathogen detection using nucleic acid amplification. For all three viruses studied, > 10% capture efficiency (< 1 Log10 loss in RT-qPCR amplifiable units) was observed. The same capture efficiencies were observed for the bacterial pathogens tested, with the exception of E. coli O157:H7 (approximately 1% capture efficiency, or 2 Log10 loss in CFU equivalents). The efficiency of the capture steps did not vary as a consequence of input target concentration or in the presence of an abundance of background microflora. A complementary plate-based capture assay showed that ApoH bound to a variety of human norovirus virus-like particles. ApoH has the potential to be a broadly reactive ligand for separating and concentrating representative foodborne pathogens, both bacteria and viruses.}, journal={JOURNAL OF MICROBIOLOGICAL METHODS}, author={Almand, Erin A. and Goulter, Rebecca M. and Jaykus, Lee-Ann}, year={2016}, month={Sep}, pages={88–95} }
 @article{aceituno_heredia_stern_bartz_venegas_solis-soto_gentry-shields_jaykus_leon_garcia_2016, title={Efficacy of two hygiene methods to reduce soil and microbial contamination on farmworker hands during harvest}, volume={59}, ISSN={["1873-7129"]}, DOI={10.1016/j.foodcont.2015.06.059}, abstractNote={To prevent fresh produce-associated outbreaks, effective hand hygiene is critical, although determining the effectiveness of hand hygiene interventions in the agricultural environment has not been well studied. The primary purpose of this study was to compare the effect of two hand hygiene interventions on the concentrations and presence of soil (A600 nm of hand rinsate) and microbes on the hands of agricultural field workers. We compared hand washing with soap, a two-step alcohol-based hand sanitizer (Two-Step ABHS) intervention, and not conducting hand hygiene (control). Hand rinsates from 159 farm workers, on two produce farms in Nuevo Leon, Mexico during May 2013, were analyzed spectrophotometrically for indicator bacteria (coliforms, Enterococcus, generic Escherichia coli), and for Bacteroidales 16s rDNA. The hand washing with soap group, compared to the control group, had significantly lower amounts of soil on hands (A600 nm 0.005 vs. A600 nm 0.236, p < 0.001), but had no significant differences in concentrations or proportions of indicator bacteria. The Two-Step ABHS group, compared to the control group, had significantly lower amounts of soil (A600 nm 0.099 vs A600 nm 0.236, p < 0.001), significantly lower concentrations of indicator bacteria (geometric mean Log CFU per hand 1.5 vs 3.3 for coliforms, p < 0.001; 3.1 vs 4.1 for Enterococcus, p < 0.05), and a significantly lower proportion of samples positive for coliforms (53% vs 100%, p < 0.001) and the Bacteroidales AllBac marker (69% vs 90%, p < 0.05). The secondary purpose of our study was to evaluate the sustained effect of hand washing and Two-Step ABHS after 30 min of jalapeño harvest. The hand washing group had significantly lower soil compared to the control group, but no group had significantly different amounts of bacteria than the control group. Two-Step ABHS may be useful for hand hygiene in an agricultural field environment, especially when soap and water are not available.}, journal={FOOD CONTROL}, author={Aceituno, Anna Fabiszewski and Heredia, Norma and Stern, Alexandra and Bartz, Faith E. and Venegas, Fabiola and Solis-Soto, Luisa and Gentry-Shields, Jennifer and Jaykus, Lee-Ann and Leon, Juan S. and Garcia, Santos}, year={2016}, month={Jan}, pages={787–792} }
 @article{moore_bobay_mertens_jaykus_2016, title={Human Norovirus Aptamer Exhibits High Degree of Target Conformation-Dependent Binding Similar to That of Receptors and Discriminates Particle Functionality}, volume={1}, ISSN={["2379-5042"]}, DOI={10.1128/msphere.00298-16}, abstractNote={Human noroviruses impose a considerable health burden globally. However, study of their inactivation is still challenging with currently reported cell culture models, as discrimination of infectious viral particles is still difficult. Traditionally, the ability of particles to bind putative carbohydrate receptors is conducted as a proxy for infectivity, but these receptors are inconsistent, expensive, and hard to purify/modify. We report a hitherto unexplored property of a different type of ligand, a nucleic acid aptamer, to mimic receptor binding behavior and assess capsid functionality for a selected strain of norovirus. These emerging ligands are cheaper, more stable, and easily synthesized/modified. The previously unutilized characteristic reported here demonstrates the fundamental potential of aptamers to serve as valuable, accessible tools for any microorganism that is difficult to cultivate/study. Therefore, this novel concept suggests a new use for aptamers that is of great value to the microbiological community—specifically that involving fastidious microbes.}, number={6}, journal={MSPHERE}, author={Moore, Matthew D. and Bobay, Benjamin G. and Mertens, Brittany and Jaykus, Lee-Ann}, year={2016} }
 @article{heredia_caballero_cardenas_molina_garcia_solis_burrowes_bartz_aceituno_jaykus_et al._2016, title={Microbial Indicator Profiling of Fresh Produce and Environmental Samples from Farms and Packing Facilities in Northern Mexico}, volume={79}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x.jfp-15-499}, abstractNote={To compare microbiological indicator and pathogen contamination among different types of fresh produce and environmental samples along the production chain, 636 samples of produce (rinsates from cantaloupe melons, jalapeño peppers, and tomatoes) and environmental samples (rinsates from hands of workers, soil, and water) were collected at four successive steps in the production process (from the field before harvest through the packing facility) on 11 farms in northern Mexico during 2011 and 2012. Samples were assayed for enteric pathogens (Escherichia coli O157:H7, other Shiga toxigenic E. coli, Salmonella, and Listeria monocytogenes) and microbial indicators (coliforms, other E. coli strains, and Enterococcus spp.). Salmonella was the only pathogen detected; it was found in one preharvest jalapeño sample (detection limits: 0.0033 CFU/ml in produce and hand samples, 0.0013 CFU/ml in water, and 0.04 CFU/g in soil). Microbial indicator profiles for produce, worker hands, and soil from jalapeño and tomato farms were similar, but cantaloupe farm samples had higher indicator levels (P < 0.05 for all comparisons) on fruit (6.5, 2.8, and 7.2 log CFU per fruit) and hands (6.6, 3.1, and 7.1 log CFU per hand) for coliforms, E. coli, and Enterococcus, respectively, and lower E. coli levels in soil (<1 CFU/g). In water from tomato farms, E. coli indicators were significantly more prevalent (70 to 89% of samples were positive; P = 0.01 to 0.02), and geometric mean levels were higher (0.3 to 0.6 log CFU/100 ml) than those in cantaloupe farm water (32 to 38% of samples were positive, geometric mean <1 CFU/100 ml). Microbial indicators were present during all production steps, but prevalence and levels were generally highest at the final on-farm production step (the packing facility) (P < 0.03 for significant comparisons). The finding that microbial contamination on produce farms is influenced by produce type and production step can inform the design of effective approaches to mitigate microbial contamination.}, number={7}, journal={JOURNAL OF FOOD PROTECTION}, author={Heredia, Norma and Caballero, Cindy and Cardenas, Carmen and Molina, Karina and Garcia, Rafael and Solis, Luisa and Burrowes, Vanessa and Bartz, Faith E. and Aceituno, Anna Fabiszewski and Jaykus, Lee-Ann and et al.}, year={2016}, month={Jul}, pages={1197–1209} }
 @inproceedings{baugher_jaykus_2016, title={Natural microbiota of raspberries (Rubus idaeus) and strawberries (Fragaria x ananassa): Microbial survey, bacterial isolation and identification, and biofilm characterization}, volume={1133}, booktitle={Xi international rubus and ribes symposium}, author={Baugher, J. L. and Jaykus, L. A.}, year={2016}, pages={521–526} }
 @article{bradshaw_jaykus_2016, title={Risk Assessment for Foodborne Viruses}, ISBN={["978-3-319-30721-3"]}, DOI={10.1007/978-3-319-30723-7_17}, journal={VIRUSES IN FOODS, 2ND EDITION}, author={Bradshaw, Elizabeth and Jaykus, Lee-Ann}, year={2016}, pages={471–503} }
 @article{bartz_hodge_heredia_aceituno_solis_jaykus_garcia_leon_2016, title={Somatic Coliphage Profiles of Produce and Environmental Samples from Farms in Northern M,xico}, volume={8}, ISSN={["1867-0342"]}, DOI={10.1007/s12560-016-9240-x}, number={3}, journal={FOOD AND ENVIRONMENTAL VIROLOGY}, author={Bartz, Faith E. and Hodge, Domonique Watson and Heredia, Norma and Aceituno, Anna Fabiszewski and Solis, Luisa and Jaykus, Lee-Ann and Garcia, Santos and Leon, Juan S.}, year={2016}, month={Sep}, pages={221–226} }
 @article{tung-thompson_libera_koch_de los reyes_jaykus_2015, title={Aerosolization of a Human Norovirus Surrogate, Bacteriophage MS2, during Simulated Vomiting}, volume={10}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0134277}, DOI={10.1371/journal.pone.0134277}, abstractNote={Human noroviruses (NoV) are the leading cause of acute gastroenteritis worldwide. Epidemiological studies of outbreaks have suggested that vomiting facilitates transmission of human NoV, but there have been no laboratory-based studies characterizing the degree of NoV release during a vomiting event. The purpose of this work was to demonstrate that virus aerosolization occurs in a simulated vomiting event, and to estimate the amount of virus that is released in those aerosols. A simulated vomiting device was constructed at one-quarter scale of the human body following similitude principles. Simulated vomitus matrices at low (6.24 mPa*s) and high (177.5 mPa*s) viscosities were inoculated with low (108 PFU/mL) and high (1010 PFU/mL) concentrations of bacteriophage MS2 and placed in the artificial “stomach” of the device, which was then subjected to scaled physiologically relevant pressures associated with vomiting. Bio aerosols were captured using an SKC Biosampler. In low viscosity artificial vomitus, there were notable differences between recovered aerosolized MS2 as a function of pressure (i.e., greater aerosolization with increased pressure), although this was not always statistically significant. This relationship disappeared when using high viscosity simulated vomitus. The amount of MS2 aerosolized as a percent of total virus “vomited” ranged from 7.2 x 10-5 to 2.67 x 10-2 (which corresponded to a range of 36 to 13,350 PFU total). To our knowledge, this is the first study to document and measure aerosolization of a NoV surrogate in a similitude-based physical model. This has implications for better understanding the transmission dynamics of human NoV and for risk modeling purposes, both of which can help in designing effective infection control measures.}, number={8}, journal={PLOS ONE}, publisher={Public Library of Science (PLoS)}, author={Tung-Thompson, Grace and Libera, Dominic A. and Koch, Kenneth L. and de los Reyes, Francis L. and Jaykus, Lee-Ann}, editor={Bauch, Chris T.Editor}, year={2015}, month={Aug}, pages={e0134277} }
 @article{fraser_wohlgenant_cates_chen_jaykus_li_chapman_2015, title={An observational study of frequency of provider hand contacts in child care facilities in North Carolina and South Carolina}, volume={43}, ISSN={["1527-3296"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84921814104&partnerID=MN8TOARS}, DOI={10.1016/j.ajic.2014.10.017}, abstractNote={Children enrolled in child care are 2.3-3.5 times more likely to experience acute gastrointestinal illness than children cared for in their own homes. The purpose of this study was to determine the frequency surfaces were touched by child care providers to identify surfaces that should be cleaned and sanitized.Observation data from a convenience sample of 37 child care facilities in North Carolina and South Carolina were analyzed. Trained data collectors used iPods (Apple, Cupertino, CA) to record hand touch events of 1 child care provider for 45 minutes in up to 2 classrooms in each facility.Across the 37 facilities, 10,134 hand contacts were observed in 51 classrooms. Most (4,536) were contacts with porous surfaces, with an average of 88.9 events per classroom observation. The most frequently touched porous surface was children's clothing. The most frequently touched nonporous surface was food contact surfaces (18.6 contacts/observation). Surfaces commonly identified as high-touch surfaces (ie, light switches, handrails, doorknobs) were touched the least.General cleaning and sanitizing guidelines should include detailed procedures for cleaning and sanitizing high-touch surfaces (ie, clothes, furniture, soft toys). Guidelines are available for nonporous surfaces but not for porous surfaces (eg, clothing, carpeting). Additional research is needed to inform the development of evidence-based practices to effectively treat porous surfaces.}, number={2}, journal={AMERICAN JOURNAL OF INFECTION CONTROL}, author={Fraser, Angela and Wohlgenant, Kelly and Cates, Sheryl and Chen, Xi and Jaykus, Lee-Ann and Li, You and Chapman, Benjamin}, year={2015}, month={Feb}, pages={107–111} }
 @article{ward_dhingra_remais_chang_johnston_jaykus_leon_2015, title={Associations between Weather and Microbial Load on Fresh Produce Prior to Harvest}, volume={78}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x.jfp-14-381}, abstractNote={Contaminated produce causes approximately 1 million cases of foodborne illness and 1 billion dollars in damages to the U.S. economy annually. The environmental conditions, especially weather, that influence the inoculation, proliferation, and dispersal of microbial load on produce are not well understood. Using a mixed models approach, we examined the relationship of temperature and precipitation to microbial indicators of contamination on fresh produce on the farm over a week-long period prior to harvest. Between 2000 and 2002, we assayed for four microbial indicators of contamination (aerobic plate count, Enterococcus, total coliforms, and Escherichia coli) on 10 produce types in 15 fields in the southern United States. The sample collection times varied, with most occurring between January and May. We collected hourly weather data for the corresponding time period and location. Our results indicated that there was a significant association between the average daily temperature (20°C) and both log aerobic plate count (e.g., an increase of 0.074 log CFU/g [standard error {SE}, 0.023] per °C increase in weekly average temperature) and log Enterococcus (e.g., an increase of 0.15 log CFU/g [SE, 0.031] per °C increase in weekly average temperature) for approximately 5 days prior to sample collection. Daily total precipitation was significantly associated with log coliforms on 2 days (∼0.11 log CFU/g [SE, 0.06] per mm of precipitation) during the week-long lag period prior to harvest. Our results suggest that microbial indicator concentrations may increase as the temperature increases. Precipitation may have a positive but complex relationship with microbial indicators, as precipitation may create moist conditions conducive to bacterial growth, spread contamination onto the field, or wash contamination off of the plant.}, number={4}, journal={JOURNAL OF FOOD PROTECTION}, author={Ward, Michelle and Dhingra, Radhika and Remais, Justin V. and Chang, Howard H. and Johnston, Lynette M. and Jaykus, Lee-Ann and Leon, Juan}, year={2015}, month={Apr}, pages={849–854} }
 @article{gentry-shields_jaykus_2015, title={Comparison of process control viruses for use in extraction and detection of human norovirus from food matrices}, volume={77}, ISSN={["1873-7145"]}, DOI={10.1016/j.foodres.2015.05.027}, abstractNote={Abstract Although RT-qPCR is a powerful tool for human norovirus (HuNoV) detection, low virus concentrations in potentially large sample volumes necessitate the use of inefficient sample processing step(s) prior to detection. Process control viruses (PCVs) are used to monitor the efficiency of these virus concentration steps. This study compared five PCVs [Mengovirus (Mengo), murine norovirus (MNV-1), MS2 coliphage, Tulane virus, and turnip crinkle virus (TCV)] to two HuNoV strains for recovery during the steps of elution, polyethylene glycol precipitation (PEG), and RNA extraction from select foods (lettuce and sliced deli ham). Results demonstrate high recovery efficiencies of HuNoV GI.6 and GII.4 using the methods described in this study: combined (sequential) losses during processing from sliced deli ham and lettuce were 10 genome equivalent copies (GEC). When considering the processing steps separately, HuNoV loss was negligible after elution, and low after PEG precipitation (mean 0.5 log 10 GEC) and RNA extraction (mean 0.1 log 10 GEC). The virus that least mimicked the behavior of HuNoV during sample processing was MNV-1. Of the viruses tested, a commercial mengovirus strain gave recovery efficiencies closest to HuNoV, showing combined losses from sliced deli ham and lettuce of 10 GEC and ~ 1 log 10 GEC, respectively. All PCVs do not behave equivalently and validation of their performance is recommended before their routine use on an application-by-application basis.}, journal={FOOD RESEARCH INTERNATIONAL}, author={Gentry-Shields, Jennifer and Jaykus, Lee-Ann}, year={2015}, month={Nov}, pages={320–325} }
 @article{manuel_moore_jaykus_2015, title={Destruction of the Capsid and Genome of GII.4 Human Norovirus Occurs during Exposure to Metal Alloys Containing Copper}, volume={81}, ISSN={["1098-5336"]}, DOI={10.1128/aem.00388-15}, abstractNote={Human norovirus (HuNoV) represents a significant public health burden worldwide and can be environmentally transmitted. Copper surfaces have been shown to inactivate the cultivable surrogate murine norovirus, but no such data exist for HuNoV. The purpose of this study was to characterize the destruction of GII.4 HuNoV and virus-like particles (VLPs) during exposure to copper alloy surfaces. Fecal suspensions positive for a GII.4 HuNoV outbreak strain or GII.4 VLPs were exposed to copper alloys or stainless steel for 0 to 240 min and recovered by elution. HuNoV genome integrity was assessed by reverse transcription-quantitative PCR (RT-qPCR) (without RNase treatment), and capsid integrity was assessed by RT-qPCR (with RNase treatment), transmission electron microscopy (TEM), SDS-PAGE/Western blot analysis, and a histo-blood group antigen (HBGA) binding assay. Exposure of fecal suspensions to pure copper for 60 min reduced the GII.4 HuNoV RNA copy number by ∼3 log10 units when analyzed by RT-qPCR without RNase treatment and by 4 log10 units when a prior RNase treatment was used. The rate of reduction of the HuNoV RNA copy number was approximately proportional to the percentage of copper in each alloy. Exposure of GII.4 HuNoV VLPs to pure-copper surfaces resulted in noticeable aggregation and destruction within 240 min, an 80% reduction in the VP1 major capsid protein band intensity in 15 min, and a near-complete loss of HBGA receptor binding within 8 min. In all experiments, HuNoV remained stable on stainless steel. These results suggest that copper surfaces destroy HuNoV and may be useful in preventing environmental transmission of the virus in at-risk settings.}, number={15}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Manuel, C. S. and Moore, M. D. and Jaykus, L. A.}, year={2015}, month={Aug}, pages={4940–4946} }
 @article{moore_escudero-abarca_suh_jaykus_2015, title={Generation and characterization of nucleic acid aptamers targeting the capsid P domain of a human norovirus GII.4 strain}, volume={209}, ISSN={["1873-4863"]}, DOI={10.1016/j.jbiotec.2015.06.389}, abstractNote={Human noroviruses (NoV) are the leading cause of acute viral gastroenteritis worldwide. Significant antigenic diversity of NoV strains has limited the availability of broadly reactive ligands for design of detection assays. The purpose of this work was to produce and characterize single stranded (ss)DNA aptamers with binding specificity to human NoV using an easily produced NoV target-the P domain protein. Aptamer selection was done using SELEX (Systematic Evolution of Ligands by EXponential enrichment) directed against an Escherichia coli-expressed and purified epidemic NoV GII.4 strain P domain. Two of six unique aptamers (designated M1 and M6-2) were chosen for characterization. Inclusivity testing using an enzyme-linked aptamer sorbent assay (ELASA) against a panel of 14 virus-like particles (VLPs) showed these aptamers had broad reactivity and exhibited strong binding to GI.7, GII.2, two GII.4 strains, and GII.7 VLPs. Aptamer M6-2 exhibited at least low to moderate binding to all VLPs tested. Aptamers significantly (p<0.05) bound virus in partially purified GII.4 New Orleans outbreak stool specimens as demonstrated by ELASA and aptamer magnetic capture (AMC) followed by RT-qPCR. This is the first demonstration of human NoV P domain protein as a functional target for the selection of nucleic acid aptamers that specifically bind and broadly recognize diverse human NoV strains.}, journal={JOURNAL OF BIOTECHNOLOGY}, author={Moore, Matthew D. and Escudero-Abarca, Blanca I. and Suh, Soo Hwan and Jaykus, Lee-Ann}, year={2015}, month={Sep}, pages={41–49} }
 @article{moore_goulter_jaykus_2015, title={Human Norovirus as a Foodborne Pathogen: Challenges and Developments}, volume={6}, ISSN={["1941-1413"]}, DOI={10.1146/annurev-food-022814-015643}, abstractNote={Human noroviruses (NoVs) are the leading cause of foodborne illness in the United States, and they exact a considerable human and economic burden worldwide. In fact, the many challenging aspects of human NoV have caused some to call it the nearly perfect foodborne pathogen. In this review, a brief overview of NoVs and their genetic structure is provided. Additionally, the challenges and recent developments related to human NoVs regarding viral evolution, transmission, epidemiology, outbreak identification, cultivation, animal and human models, and detection are presented.}, journal={ANNUAL REVIEW OF FOOD SCIENCE AND TECHNOLOGY, VOL 6}, author={Moore, Matthew D. and Goulter, Rebecca M. and Jaykus, Lee-Ann}, year={2015}, pages={411–433} }
 @misc{uyttendaele_jaykus_amoah_chiodini_cunliffe_jacxsens_holvoet_korsten_lau_mcclure_et al._2015, title={Microbial Hazards in Irrigation Water: Standards, Norms, and Testing to Manage Use of Water in Fresh Produce Primary Production}, volume={14}, ISSN={["1541-4337"]}, DOI={10.1111/1541-4337.12133}, abstractNote={Accessibility to abundant sources of high-quality water is integral to the production of safe and wholesome fresh produce. However, access to safe water is becoming increasingly difficult in many parts of the world, and this can lead to the production of fresh produce contaminated with pathogenic microorganisms, resulting in increased risk of human disease. Water, an important raw material in the fresh produce chain, is used in considerable amounts in many operations, including irrigation and application of pesticides and fertilizers, but also as a transport medium and for cooling and washing in postharvest practices. In several reported outbreaks related to uncooked fruit and vegetable products, water has been identified as a likely source of the outbreak. The present study, initiated by the ILSI Europe Emerging Microbiological Issues Task Force in collaboration with 8 other ILSI branches and support of WHO/FAO, was undertaken to review the status of, and provide suggestions for, consideration by different stakeholders on water and sanitation and its impact on food safety and public health. A limited number of guidelines and regulations on water quality for agricultural production are available, and many of them are still heavily based on microbial standards and (debated) parameters such as fecal coliforms. Data gaps have been identified with regard to baseline studies of microbial pathogens in water sources in many regions, the need for agreement on methods and microbial parameters to be used in assessing water quality, the fate of pathogens in water, and their transfer and persistence on irrigated/processed produce.}, number={4}, journal={COMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY}, author={Uyttendaele, Mieke and Jaykus, Lee-Ann and Amoah, Philip and Chiodini, Alessandro and Cunliffe, David and Jacxsens, Liesbeth and Holvoet, Kevin and Korsten, Lise and Lau, Mathew and McClure, Peter and et al.}, year={2015}, month={Jul}, pages={336–356} }
 @article{tung-thompson_gentry-shields_fraser_jaykus_2015, title={Persistence of Human Norovirus RT-qPCR Signals in Simulated Gastric Fluid}, volume={7}, ISSN={["1867-0342"]}, DOI={10.1007/s12560-014-9170-4}, number={1}, journal={FOOD AND ENVIRONMENTAL VIROLOGY}, author={Tung-Thompson, Grace and Gentry-Shields, Jennifer and Fraser, Angela and Jaykus, Lee-Ann}, year={2015}, month={Mar}, pages={32–40} }
 @article{heredia_solis-soto_venegas_bartz_aceituno_jaykus_leon_garcia_2015, title={Validation of a novel rinse and filtration method for efficient processing of fresh produce samples for microbiological indicator enumeration}, volume={78}, DOI={10.4315/0362-028x.jfp-14-324}, abstractNote={Several methods have been described to prepare fresh produce samples for microbiological analysis, each with its own advantages and disadvantages. The aim of this study was to compare the performance of a novel combined rinse and membrane filtration method to two alternative sample preparation methods for the quantification of indicator microorganisms from fresh produce. Decontaminated cantaloupe melons and jalapeño peppers were surface inoculated with a cocktail containing 10(6) CFU/ml Escherichia coli, Salmonella Typhimurium, and Enterococcus faecalis. Samples were processed using a rinse and filtration method, homogenization by stomacher, or a sponge-rubbing method, followed by quantification of bacterial load using culture methods. Recovery efficiencies of the three methods were compared. On inoculated cantaloupes, the rinse and filtration method had higher recovery of coliforms (0.95 log CFU/ml higher recovery, P = 0.0193) than the sponge-rubbing method. Similarly, on inoculated jalapeños, the rinse and filtration method had higher recovery for coliforms (0.84 log CFU/ml higher, P = 0.0130) and E. coli (1.46 log CFU/ml higher, P < 0.0001) than the sponge-rubbing method. For jalapeños, the rinse and filtration method outperformed the homogenization method for all three indicators (0.79 to 1.71 log CFU/ml higher, P values ranging from 0.0075 to 0.0002). The precision of the three methods was also compared. The precision of the rinse and filtration method was similar to that of the other methods for recovery of two of three indicators from cantaloupe (E. coli P = 0.7685, E. faecalis P = 0.1545) and was more precise for recovery of two of three indicators from jalapeño (coliforms P = 0.0026, E. coli P = 0.0243). Overall, the rinse and filtration method performed equivalent to, and sometimes better than, either of the compared methods. The rinse and filtration method may have logistical advantages when processing large numbers of samples, improving sampling efficiency and facilitating microbial detection.}, number={3}, journal={Journal of Food Protection}, author={Heredia, N. and Solis-Soto, L. and Venegas, F. and Bartz, F. E. and Aceituno, A. F. and Jaykus, L. A. and Leon, J. S. and Garcia, S.}, year={2015}, pages={525–530} }
 @misc{de keuckelaere_jacxsens_amoah_medema_mcclure_jaykus_uyttendaele_2015, title={Zero Risk Does Not Exist: Lessons Learned from Microbial Risk Assessment Related to Use of Water and Safety of Fresh Produce}, volume={14}, ISSN={["1541-4337"]}, DOI={10.1111/1541-4337.12140}, abstractNote={Risk assessments related to use of water and safety of fresh produce originate from both water and food microbiology studies. Although the set-up and methodology of risk assessment in these 2 disciplines may differ, analysis of the current literature reveals some common outcomes. Most of these studies from the water perspective focus on enteric virus risks, largely because of their anticipated high concentrations in untreated wastewater and their resistance to common wastewater treatments. Risk assessment studies from the food perspective, instead, focus mainly on bacterial pathogens such as Salmonella and pathogenic Escherichia coli. Few site-specific data points were available for most of these microbial risk assessments, meaning that many assumptions were necessary, which are repeated in many studies. Specific parameters lacking hard data included rates of pathogen transfer from irrigation water to crops, pathogen penetration, and survival in or on food crops. Data on these factors have been investigated over the last decade and this should improve the reliability of future microbial risk estimates. However, the sheer number of different foodstuffs and pathogens, combined with water sources and irrigation practices, means that developing risk models that can span the breadth of fresh produce safety will be a considerable challenge. The new approach using microbial risk assessment is objective and evidence-based and leads to more flexibility and enables more tailored risk management practices and guidelines. Drawbacks are, however, capacity and knowledge to perform the microbial risk assessment and the need for data and preferably data of the specific region. This manuscripts intends to give an extensive overview of approaches and challenges of past and future quantitative microbial risk assessment studies in the fresh produce chain related to the use of water in order to aid further research efforts in this area.}, number={4}, journal={COMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY}, author={De Keuckelaere, Ann and Jacxsens, Liesbeth and Amoah, Philip and Medema, Gertjan and McClure, Peter and Jaykus, Lee-Ann and Uyttendaele, Mieke}, year={2015}, month={Jul}, pages={387–410} }
 @article{suh_dwivedi_jaykus_2014, title={Development and evaluation of aptamer magnetic capture assay in conjunction with real-time PCR for detection of Campylobacter jejuni}, volume={56}, ISSN={["1096-1127"]}, DOI={10.1016/j.lwt.2013.12.012}, abstractNote={Abstract A prototype method for the concentration and detection of Campylobacter jejuni was developed using a previously reported biotinylated DNA aptamer in conjunction with qPCR. The so-called aptamer-based magnetic capture-qPCR (AMC-qPCR) assay was compared to a similar immunomagnetic separation (IMS)-qPCR assay. In small volume experiments (300 μl) applied to serially diluted C. jejuni suspended in buffer containing a mixed culture of other common food borne pathogens, the lower detection limit of the AMC-qPCR method was 1.1 log 10 /300 μl C. jejuni cells, one log 10 better (lower) than that of IMS-qPCR (2.1 log 10  CFU/300 μl). AMC-qPCR capture efficiency was 10–13% at assay detection limit. In 10 ml scale-up experiments, the lower detection limit of AMC-qPCR was 2.0 log 10  CFU/10 ml with corresponding capture efficiency of 4–7%. Nucleic acid aptamers are promising alternatives to antibodies for magnetic bead-based capture followed by qPCR detection.}, number={2}, journal={LWT-FOOD SCIENCE AND TECHNOLOGY}, author={Suh, Soo Hwan and Dwivedi, Had P. and Jaykus, Lee-Ann}, year={2014}, month={May}, pages={256–260} }
 @article{jaykus_meschke_2014, title={Editorial overview: Environmental virology}, volume={4}, ISSN={["1879-6257"]}, DOI={10.1016/j.coviro.2014.01.007}, journal={CURRENT OPINION IN VIROLOGY}, author={Jaykus, Lee-Ann and Meschke, John Scott}, year={2014}, month={Feb}, pages={VII-IX} }
 @article{li_jaykus_cates_wohlgenant_chen_fraser_2014, title={Hygienic conditions in child-care facilities in North Carolina and South Carolina: An integrated microbial and observational study}, volume={42}, ISSN={["1527-3296"]}, DOI={10.1016/j.ajic.2014.03.009}, abstractNote={In the United States almost one-quarter (23%) of children younger than age 5 years participate in some form of out-of-home child care; these children are 2.3-3.5 times more likely to contract acute gastrointestinal illness.Observational investigations were done to understand the hygienic conditions and practices of 40 child-care facilities in North Carolina and South Carolina. These data were compared with microbiological indicator data (aerobic plate counts and coliform counts) collected from selected surfaces in each facility. Results from the two data sets were analyzed using nonparametric statistical methods to reveal potential risk factors for enteric disease transmission.Statistically significant differences (P ≤ .05) in surface microbial counts were observed when comparing family child-care homes versus centers and between facilities participating in the Child and Adult Care Food Program and those that do not participate. Facilities without written surface cleaning or food preparation policies had statistically significantly higher microbial counts on surfaces.Our unique study, which combined observational and microbiological data, provided revealing information about the relationship between hygiene indicators and sanitary practices in child-care facilities in the southeastern United States.}, number={7}, journal={AMERICAN JOURNAL OF INFECTION CONTROL}, author={Li, You and Jaykus, Lee-Ann and Cates, Sheryl and Wohlgenant, Kelly and Chen, Xi and Fraser, Angela M.}, year={2014}, month={Jul}, pages={781–786} }
 @article{li_fraser_chen_cates_wohlgenant_jaykus_2014, title={Microbiological analysis of environmental samples collected from child care facilities in North and South Carolina}, volume={42}, ISSN={["1527-3296"]}, DOI={10.1016/j.ajic.2014.06.030}, abstractNote={•Surface and care providers' hands from 40 child care facilities in North and South Carolina were subjected to microbiological analysis. •Overall, hands had higher microbial loads than surfaces. •Biotype I Escherichia coli was absent; pathogens Salmonella enterica, E coli O157, Campylobacter jejuni, and Shigella spp were also absent. •Four samples showed evidence of human norovirus contamination. •Results suggest that these facilities practiced good hygiene and sanitation. Background Children cared for outside the home are at an increased risk of enteric disease. Microbiological analyses were performed on environmental samples collected from child care facilities in North and South Carolina. Methods There were 326 samples collected from 40 facilities corresponding to common surfaces (77% of samples) and the hands of care providers (23% of samples). Samples were analyzed for total aerobic plate counts (APCs), total coliforms, biotype I Escherichia coli, and pathogens Shigella spp, Salmonella enterica, E coli O157, Campylobacter jejuni, and human norovirus. Results Median APCs and coliform counts for hands were 4.6 and 1.0 log10 colony-forming units (CFU) per hand, respectively. Median APCs for surfaces were 2.0 and 2.6 log10 CFU for flat and irregular surfaces, respectively. Coliforms were detected in 16% of samples, with counts ranging from 1.0 log10 to >4.3 log10 CFU, with higher counts most often observed for hand rinse samples. Biotype I E coli counts were below assay detection limits (<1 log10 CFU) for all but 1 sample. No samples were positive for any of the 4 bacterial pathogens, whereas 4 samples showed evidence of human norovirus RNA. Conclusion The relative absence of pathogens and biotype I E coli in environmental samples suggests the child care facilities sampled in this study managed fecal contamination well. Children cared for outside the home are at an increased risk of enteric disease. Microbiological analyses were performed on environmental samples collected from child care facilities in North and South Carolina. There were 326 samples collected from 40 facilities corresponding to common surfaces (77% of samples) and the hands of care providers (23% of samples). Samples were analyzed for total aerobic plate counts (APCs), total coliforms, biotype I Escherichia coli, and pathogens Shigella spp, Salmonella enterica, E coli O157, Campylobacter jejuni, and human norovirus. Median APCs and coliform counts for hands were 4.6 and 1.0 log10 colony-forming units (CFU) per hand, respectively. Median APCs for surfaces were 2.0 and 2.6 log10 CFU for flat and irregular surfaces, respectively. Coliforms were detected in 16% of samples, with counts ranging from 1.0 log10 to >4.3 log10 CFU, with higher counts most often observed for hand rinse samples. Biotype I E coli counts were below assay detection limits (<1 log10 CFU) for all but 1 sample. No samples were positive for any of the 4 bacterial pathogens, whereas 4 samples showed evidence of human norovirus RNA. The relative absence of pathogens and biotype I E coli in environmental samples suggests the child care facilities sampled in this study managed fecal contamination well.}, number={10}, journal={AMERICAN JOURNAL OF INFECTION CONTROL}, author={Li, You and Fraser, Angela and Chen, Xi and Cates, Sheryl and Wohlgenant, Kelly and Jaykus, Lee-Ann}, year={2014}, month={Oct}, pages={1049–1055} }
 @article{escudero-abarca_rawsthorne_goulter_suh_jaykus_2014, title={Molecular methods used to estimate thermal inactivation of a prototype human norovirus: More heat resistant than previously believed?}, volume={41}, ISSN={["1095-9998"]}, DOI={10.1016/j.fm.2014.01.009}, abstractNote={Two molecular-based methods for estimating capsid integrity as a proxy for virus infectivity were used to produce thermal inactivation profiles of Snow Mountain virus (SMV), a prototype human norovirus (HuNoV). Monodispersed virus suspensions were exposed to 77, 80, 82 and 85 °C for various times, pre-treated with either propidium monoazide (PMA) or RNase, and subjected to RNA isolation followed by RT-qPCR amplification. D-values were 25.6 ± 2.8, 3.1 ± 0.1, 0.7 ± 0.04 and 0.2 ± 0.07 min at 77, 80, 82 and 85 °C, respectively for PMA-treated SMV; and 16.4 ± 0.4, 3.9 ± 0.2 0.9 ± 0.3 and 0.12 ± 0.00 min at 77, 80, 82 and 85 °C, respectively for RNase-treated SMV. Corresponding zD values were 3.80 °C and 3.71 °C for PMA and RNase-treated virus, respectively. Electron microscopy data applied to heat-treated virus-like particles supported this relatively high degree of thermal resistance. The data suggest that SMV is more heat resistant than common cultivable HuNoV surrogates. Standardized thermal inactivation methods (such as milk pasteurization) may not be stringent enough to eliminate this virus and perhaps other HuNoV.}, journal={FOOD MICROBIOLOGY}, author={Escudero-Abarca, B. I. and Rawsthorne, H. and Goulter, R. M. and Suh, S. H. and Jaykus, L. A.}, year={2014}, month={Aug}, pages={91–95} }
 @article{wohlgenant_cates_fraser_chapman_jaykus_chen_2014, title={Sanitation in classroom and food preparation areas in child-care facilities in North Carolina and South Carolina}, volume={77}, number={4}, journal={Journal of Environmental Health}, author={Wohlgenant, K. C. and Cates, S. C. and Fraser, A. and Chapman, B. and Jaykus, L. A. and Chen, X.}, year={2014}, pages={20–27} }
 @article{suh_dwivedi_choi_jaykus_2014, title={Selection and characterization of DNA aptamers specific for Listeria species}, volume={459}, ISSN={["1096-0309"]}, DOI={10.1016/j.ab.2014.05.006}, abstractNote={Single-stranded (ss) DNA aptamers with binding affinity to Listeria spp. were selected using a whole-cell SELEX (Systematic Evolution of Ligands by EXponential enrichment) method. Listeria monocytogenes cells were grown at 37°C and harvested at mid-log phase or early stationary phase to serve as the targets in SELEX. A total of 10 unique aptamer sequences were identified, six associated with log phase cells and four with stationary phase cells. Binding affinity of the aptamers was determined using flow cytometry and ranged from 10% to 44%. Four candidates having high binding affinity were further studied and found to show genus-specific binding affinity when screened against five different species within the Listeria genus. Using sequential binding assays combined with flow cytometry, it was determined that three of the aptamers (LM6-2, LM12-6, and LM12-13) bound to one apparent cell surface moiety, while a fourth aptamer (LM6-116) appeared to bind to a different cell surface region. This is the first study in which SELEX targeted bacterial cells at different growth phases. When used together, aptamers that bind to different cell surface moieties could increase the analytical sensitivity of future capture and detection assays.}, journal={ANALYTICAL BIOCHEMISTRY}, author={Suh, Soo Hwan and Dwivedi, Hari P. and Choi, Soo Jung and Jaykus, Lee-Ann}, year={2014}, month={Aug}, pages={39–45} }
 @article{escudero-abarca_suh_moore_dwivedi_jaykus_2014, title={Selection, Characterization and Application of Nucleic Acid Aptamers for the Capture and Detection of Human Norovirus Strains}, volume={9}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0106805}, abstractNote={Human noroviruses (HuNoV) are the leading cause of acute viral gastroenteritis and an important cause of foodborne disease. Despite their public health significance, routine detection of HuNoV in community settings, or food and environmental samples, is limited, and there is a need to develop alternative HuNoV diagnostic reagents to complement existing ones. The purpose of this study was to select and characterize single-stranded (ss)DNA aptamers with binding affinity to HuNoV. The utility of these aptamers was demonstrated in their use for capture and detection of HuNoV in outbreak-derived fecal samples and a representative food matrix. SELEX (Systematic Evolution of Ligands by EXponential enrichment) was used to isolate ssDNA aptamer sequences with broad reactivity to the prototype GII.2 HuNoV strain, Snow Mountain Virus (SMV). Four aptamer candidates (designated 19, 21, 25 and 26) were identified and screened for binding affinity to 14 different virus-like particles (VLPs) corresponding to various GI and GII HuNoV strains using an Enzyme-Linked Aptamer Sorbant Assay (ELASA). Collectively, aptamers 21 and 25 showed affinity to 13 of the 14 VLPs tested, with strongest binding to GII.2 (SMV) and GII.4 VLPs. Aptamer 25 was chosen for further study. Its binding affinity to SMV-VLPs was equivalent to that of a commercial antibody within a range of 1 to 5 µg/ml. Aptamer 25 also showed binding to representative HuNoV strains present in stool specimens obtained from naturally infected individuals. Lastly, an aptamer magnetic capture (AMC) method using aptamer 25 coupled with RT-qPCR was developed for recovery and detection of HuNoV in artificially contaminated lettuce. The capture efficiency of the AMC was 2.5–36% with an assay detection limit of 10 RNA copies per lettuce sample. These ssDNA aptamer candidates show promise as broadly reactive reagents for use in HuNoV capture and detection assays in various sample types.}, number={9}, journal={PLOS ONE}, author={Escudero-Abarca, Blanca I. and Suh, Soo Hwan and Moore, Matthew D. and Dwivedi, Hari P. and Jaykus, Lee-Ann}, year={2014}, month={Sep} }
 @article{thomas_chapman_jaykus_phister_2014, title={Tracing Temperature Patterns of Cut Leafy Greens during Service in North Carolina School Food Service}, volume={77}, ISSN={["1944-9097"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84906969253&partnerID=MN8TOARS}, DOI={10.4315/0362-028x.jfp-14-121}, abstractNote={Contaminated fresh produce has been increasingly identified as a cause of foodborne illnesses. Because of concerns about pathogen growth on these food items at retail, the 2009 U.S. Food and Drug Administration Food Code established that cut leafy greens (lettuce, spinach, spring mix, cabbage, arugula, and kale) must have time and temperature controls for safety and hence should be kept at refrigerated temperatures (5°C or lower). The purpose of this study was to determine the temperature profiles of cut leafy greens in single-serving clamshell containers provided as part of the North Carolina School Lunch Program and to compare the two policies that North Carolina has in place to control the temperature of these products (the 3-day rule and time in lieu of temperature). Temperatures were recorded with data loggers in 24 schools during a 3-day period. In all cases, substantial temperature variability was found for these products, including temperatures above 5°C for at least 1 h on each of the 3 days. In some cases, temperatures reached above 5°C for more than 3 h throughout the serving time. The results demonstrate the importance of developing a protocol for continuous temperature monitoring of leafy greens served in school lunch programs.}, number={9}, journal={JOURNAL OF FOOD PROTECTION}, author={Thomas, Ellen M. and Chapman, Benjamin and Jaykus, Lee-Ann and Phister, Trevor}, year={2014}, month={Sep}, pages={1495–1500} }
 @article{ravaliya_gentry-shields_garcia_heredia_aceituno_bartz_leon_jaykus_2014, title={Use of Bacteroidales Microbial Source Tracking To Monitor Fecal Contamination in Fresh Produce Production}, volume={80}, ISSN={["1098-5336"]}, DOI={10.1128/aem.02891-13}, abstractNote={ABSTRACT In recent decades, fresh and minimally processed produce items have been associated with an increasing proportion of food-borne illnesses. Most pathogens associated with fresh produce are enteric (fecal) in origin, and contamination can occur anywhere along the farm-to-fork chain. Microbial source tracking (MST) is a tool developed in the environmental microbiology field to identify and quantify the dominant source(s) of fecal contamination. This study investigated the utility of an MST method based on Bacteroidales 16S rRNA gene sequences as a means of identifying potential fecal contamination, and its source, in the fresh produce production environment. The method was applied to rinses of fresh produce, source and irrigation waters, and harvester hand rinses collected over the course of 1 year from nine farms (growing tomatoes, jalapeño peppers, and cantaloupe) in Northern Mexico. Of 174 samples, 39% were positive for a universal Bacteroidales marker (AllBac), including 66% of samples from cantaloupe farms (3.6 log 10 genome equivalence copies [GEC]/100 ml), 31% of samples from tomato farms (1.7 log 10 GEC/100 ml), and 18% of samples from jalapeño farms (1.5 log 10 GEC/100 ml). Of 68 AllBac-positive samples, 46% were positive for one of three human-specific markers, and none were positive for a bovine-specific marker. There was no statistically significant correlation between Bacteroidales and generic Escherichia coli across all samples. This study provides evidence that Bacteroidales markers may serve as alternative indicators for fecal contamination in fresh produce production, allowing for determination of both general contamination and that derived from the human host.}, number={2}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Ravaliya, Kruti and Gentry-Shields, Jennifer and Garcia, Santos and Heredia, Norma and Aceituno, Anna Fabiszewski and Bartz, Faith E. and Leon, Juan S. and Jaykus, Lee-Ann}, year={2014}, month={Jan}, pages={612–617} }
 @article{tung_macinga_arbogast_jaykus_2013, title={Efficacy of Commonly Used Disinfectants for Inactivation of Human Noroviruses and Their Surrogates}, volume={76}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x.jfp-12-532}, abstractNote={Human noroviruses (HuNoVs) are the most common cause of acute viral gastroenteritis worldwide and are a leading cause of foodborne disease. Their environmental persistence and purported resistance to disinfection undoubtedly contribute to their success as foodborne disease agents. The purpose of this study was to compare the efficacy of three commonly used disinfectant active ingredients against representative HuNoV strains and cultivable surrogates. Ethanol (50, 70, and 90%), sodium hypochlorite (5, 75, 250, 500, and 1,000 ppm), and a quaternary ammonium compound blend (at 0.1×, 1.0×, and 10× concentrations) were evaluated against two norovirus (NoV) genogroup II strains (GII.2 and GII.4) and two surrogates (feline calicivirus [FCV] and murine norovirus [MNV-1]). Virucidal suspension assays (30-s exposure) were conducted in accordance with ASTM International standard E-1052. Virus inactivation was quantified using reverse transcription quantitative PCR targeting the ORFI-ORFII junction (HuNoV), the RNA polymerase region (MNV-1), or the ORFI region (FCV); infectivity assays were also performed for MNV-1 and FCV. The two HuNoV strains and FCV were relatively resistant to ethanol (<0.5 log inactivation) irrespective of concentration, but MNV-1 was much more susceptible (log inactivation, ∼2.0 log at higher ethanol concentrations). Both HuNoV strains were more resistant to hypochlorite than were either of the animal surrogates, with the human strains requiring ≥500 ppm of hypochlorite to achieve statistically significant reduction (≥3.0 log) in virus concentration. All four viruses were resistant to inactivation (<0.5-log reduction) using the quaternary ammonium compound formulation at all concentrations tested. This study is novel in that it clearly demonstrates the relative ineffectiveness of common active disinfectant ingredients against HuNoV and highlights the fact that the cultivable surrogates do not always mimic HuNoV strains.}, number={7}, journal={JOURNAL OF FOOD PROTECTION}, author={Tung, Grace and Macinga, David and Arbogast, James and Jaykus, Lee-Ann}, year={2013}, month={Jul}, pages={1210–1217} }
 @article{liu_escudero_jaykus_montes_goulter_lichtenstein_fernandez_lee_de nardo_kirby_et al._2013, title={Laboratory Evidence of Norwalk Virus Contamination on the Hands of Infected Individuals}, volume={79}, ISSN={["1098-5336"]}, DOI={10.1128/aem.02576-13}, abstractNote={Human norovirus (NoV) outbreak investigations suggest that the hands of infected individuals play an important role in NoV transmission. However, there is no experimental evidence documenting the likelihood and degree of NoV contamination on hands. As part of a clinical trial designed to evaluate the efficacy of high-pressure processing for Norwalk virus (NV) inactivation in oysters, 159 hand rinse samples were collected from 6 infected and 6 uninfected subjects. NV was concentrated from the samples by polyethylene glycol precipitation, followed by RNA extraction using an automated guanidinium isothiocyanate-silica method. NV RNA was detected and quantified using multiple NV-specific reverse transcription-quantitative PCR (RT-qPCR) assays. A total of 25.4% (18/71) of the hand rinse samples collected from 6 infected volunteers were presumptively positive for NV, with an average of 3.86 log10 genomic equivalent copies (GEC) per hand. Dot blot hybridization of PCR products obtained using a different primer set, and DNA sequencing of selected amplicons, provided further confirmation of the presence of NV in the hand rinses. NV contamination was also detected in two hand rinse samples obtained from one uninfected subject. These findings provide definitive evidence of NV contamination on the hands of infected subjects observed under controlled clinical research conditions. Such data support the need for better hand hygiene strategies to prevent NoV transmission.}, number={24}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Liu, Pengbo and Escudero, Blanca and Jaykus, Lee-Ann and Montes, Julia and Goulter, Rebecca M. and Lichtenstein, Meredith and Fernandez, Marina and Lee, Joong-Chul and De Nardo, Elizabeth and Kirby, Amy and et al.}, year={2013}, month={Dec}, pages={7875–7881} }
 @article{suh_jaykus_2013, title={Nucleic acid aptamers for capture and detection of Listeria spp}, volume={167}, ISSN={["1873-4863"]}, DOI={10.1016/j.jbiotec.2013.07.027}, abstractNote={The purpose of this study was to identify biotinylated single-stranded (ss) DNA aptamers with binding specificity to Listeria and use these for capture and subsequent qPCR detection of the organism. For aptamer selection, SELEX (systematic evolution of ligands by exponential enrichment) was applied to a biotin-labeled ssDNA combinatorial library. After multiple rounds of selection and counter-selection, aptamers separated, sequenced, and characterized by flow cytometry showed binding affinities to L. monocytogenes of 18-23%. Although selected for using L. monocytogenes, these aptamers showed similar binding affinity for other members of the Listeria genus and low binding affinity for non-Listeria species. One aptamer, Lbi-17, was chosen for development of a prototype capture and detection assay. When Lbi-17 was conjugated to magnetic beads and used in a combined aptamer magnetic capture (AMC)-qPCR assay, the pathogen could be detected at concentrations <60 CFU/500 μl buffer in the presence of a heterogeneous cocktail of non-Listeria bacterial cells, with a capture efficiency of 26-77%. Parallel experiments using immunomagnetic separation (IMS)-qPCR produced the same detection limit but lower capture efficiency (16-21%). Increasing assay volume to 10 and 50 ml resulted in reduced capture efficiency and higher limits of detection, at 2.7 and 4.8 log₁₀ CFU L. monocytogenes per sample, respectively, for the AMC-qPCR assay. Biotinylated ssDNA aptamers are promising ligands for food-borne pathogen concentration prior to detection using molecular methods.}, number={4}, journal={JOURNAL OF BIOTECHNOLOGY}, author={Suh, Soo Hwan and Jaykus, Lee-Ann}, year={2013}, month={Sep}, pages={454–461} }
 @article{dwivedi_smiley_jaykus_2013, title={Selection of DNA aptamers for capture and detection of Salmonella Typhimurium using a whole-cell SELEX approach in conjunction with cell sorting}, volume={97}, ISSN={["1432-0614"]}, DOI={10.1007/s00253-013-4766-4}, number={8}, journal={APPLIED MICROBIOLOGY AND BIOTECHNOLOGY}, author={Dwivedi, Hari P. and Smiley, R. Derike and Jaykus, Lee-Ann}, year={2013}, month={Apr}, pages={3677–3686} }
 @article{escudero_rawsthorne_gensel_jaykus_2012, title={Persistence and Transferability of Noroviruses on and between Common Surfaces and Foods}, volume={75}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x.jfp-11-460}, abstractNote={Human noroviruses (HuNoV) are the leading cause of foodborne disease, and poor personal hygiene practices of infected workers are the most common mode of contamination. The purpose of this study was to characterize the persistence and transferability of representative noroviruses Norwalk virus (NV), Snow Mountain virus (SMV), and murine norovirus 1 (MNV-1) on and between solid surfaces and foods. Changes in virus concentration on artificially inoculated solid surfaces (stainless steel, ceramic, and Formica) or lettuce were monitored over a period of 14 to 42 days. Virus transfer was evaluated from donor (solid surface) to recipient (food, e.g., lettuce and sliced turkey deli meat) for up to 2 h postinoculation. Viruses were recovered by elution and titered with reverse transcription quantitative PCR (RT-qPCR) and/or infectivity assay, as appropriate. Based on RT-qPCR, the concentration of NV and SMV on surfaces dropped gradually over time, with an average reduction of 1.5 to 2.0 and 1.8 to 2.3 log, respectively, after 42 days, with no statistically significant differences by surface. When inoculated onto lettuce stored for 2 weeks at 4°C and room temperature, the titers of NV and SMV dropped by approximately 1.0 and 1.2 to 1.8 log, respectively. Comparatively, the RT-qPCR signal associated with purified HuNoV RNA placed on the same surfaces was more rapidly lost to degradation. Transfer efficiency ranged from 0 to 26% for lettuce and from 55 to 95% for sliced turkey deli meat, with statistically significant differences (P ≤ 0.05) in transferability as a function of contact pressure (100 and 1,000 g/9 cm2) and inoculum drying time. When similar experiments were done with MNV-1, infectious virus failed to be detected on solid surfaces after storage day 21, although the virus did persist on lettuce. This study provides much needed quantitative data for use in risk assessment efforts intended to characterize the transmission of HuNoV during food preparation and handling.}, number={5}, journal={JOURNAL OF FOOD PROTECTION}, author={Escudero, B. I. and Rawsthorne, H. and Gensel, C. and Jaykus, L. A.}, year={2012}, month={May}, pages={927–935} }
 @article{liu_jaykus_wong_moe_2012, title={Persistence of Norwalk Virus, Male-Specific Coliphage, and Escherichia coli on Stainless Steel Coupons and in Phosphate-Buffered Saline}, volume={75}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x.jfp-12-197}, abstractNote={Human noroviruses (NoVs) are a leading cause of acute gastroenteritis and are frequently transmitted by contaminated food, water, hands, and environmental surfaces. Little is known about their environmental stability and/or which alternative microorganisms can serve as effective surrogates. To examine whether Escherichia coli and male-specific coliphage MS2 can be appropriate surrogates for NoVs, approximately 6.8 log genomic equivalent copies of Norwalk virus (NV), and 6.0 to 6.5 log PFU or CFU of MS2 and E. coli, respectively, were inoculated onto stainless steel coupons and held at 4°C, room temperature (RT), or 37°C over a period of 75 min (E. coli and MS2) to 4 weeks. These three microorganisms were also seeded into phosphate-buffered saline (PBS) and sampled at different time intervals for up to 6 weeks. MS2 and E. coli survived approximately 15 min at 37°C, 45 min at RT, and 60 min at 4°C on the stainless steel surfaces. In contrast, NV RNA titers were reduced by only 2.4 log at 37°C, 1.5 log at RT, and 0.9 log at 4°C after 4 weeks. MS2 and E. coli were able to survive at least 5 weeks in PBS at 4°C and RT, and NV was stable in PBS at 4°C and RT for at least 6 weeks. However, E. coli, MS2, and NV were completely inactivated after 1-, 4-, and 5-week incubations in PBS at 37°C, respectively. These findings indicate that NoVs are highly persistent on environmental surfaces and in PBS solution at different temperatures. While E. coli does not appear to be an appropriate surrogate for NoVs, MS2 could be more relevant for modeling the environmental persistence of NoVs under wet conditions, but not under dry conditions.}, number={12}, journal={JOURNAL OF FOOD PROTECTION}, author={Liu, Pengbo and Jaykus, Lee-Ann and Wong, Esther and Moe, Christine}, year={2012}, month={Dec}, pages={2151–2157} }
 @article{heldt_gurgel_jaykus_carbonell_2012, title={Porcine parvovirus removal using trimer and biased hexamer peptides}, volume={7}, ISSN={1860-6768}, url={http://dx.doi.org/10.1002/biot.201000397}, DOI={10.1002/biot.201000397}, abstractNote={Assuring the microbiological safety of biological therapeutics remains an important concern. Our group has recently reported small trimeric peptides that have the ability to bind and remove a model nonenveloped virus, porcine parvovirus (PPV), from complex solutions containing human blood plasma. In an effort to improve the removal efficiency of these small peptides, we created a biased library of hexamer peptides that contains two previously reported trimeric peptides designated WRW and KYY. This library was screened and several hexamer peptides were discovered that also removed PPV from solution, but there was no marked improvement in removal efficiency when compared to the trimeric peptides. Based on simulated docking experiments, it appeared that hexamer peptide binding is dictated more by secondary structure, whereas the binding of trimeric peptides is dominated by charge and hydrophobicity. This study demonstrates that trimeric and hexameric peptides may have different, matrix-specific roles to play in virus removal applications. In general, the hexamer ligand may perform better for binding of specific viruses, whereas the trimer ligand may have more broadly reactive virus-binding properties.}, number={4}, journal={Biotechnology Journal}, publisher={Wiley}, author={Heldt, Caryn L. and Gurgel, Patrick V. and Jaykus, Lee-Ann and Carbonell, Ruben G.}, year={2012}, month={Apr}, pages={558–565} }
 @misc{dwivedi_jaykus_2011, title={Detection of pathogens in foods: the current state-of-the-art and future directions}, volume={37}, ISSN={["1549-7828"]}, DOI={10.3109/1040841x.2010.506430}, abstractNote={Over the last fifty years, microbiologists have developed reliable culture-based techniques to detect food borne pathogens. Although these are considered to be the “gold-standard,” they remain cumbersome and time consuming. Despite the advent of rapid detection methods such as ELISA and PCR, it is clear that reduction and/or elimination of cultural enrichment will be essential in the quest for truly real-time detection methods. As such, there is an important role for bacterial concentration and purification from the sample matrix as a step preceding detection, so-called pre-analytical sample processing. This article reviews recent advancements in food borne pathogen detection and discusses future methods with a focus on pre-analytical sample processing, culture independent methods, and biosensors.}, number={1}, journal={CRITICAL REVIEWS IN MICROBIOLOGY}, author={Dwivedi, Hari P. and Jaykus, Lee-Ann}, year={2011}, month={Feb}, pages={40–63} }
 @article{anderson_jaykus_beaulieu_dennis_2011, title={Pathogen-produce pair attribution risk ranking tool to prioritize fresh produce commodity and pathogen combinations for further evaluation (P(3)ARRT)}, volume={22}, ISSN={["1873-7129"]}, DOI={10.1016/j.foodcont.2011.04.028}, abstractNote={Foodborne disease outbreaks and cases associated with fresh produce have increased over the past decade. In developing approaches to prevent or reduce illnesses from consumption of contaminated produce, new tools are needed to identify and prioritize appropriate efforts. The purpose of this study was to develop a semi-quantitative risk ranking tool (Pathogen-Produce Pair Attribution Risk Ranking Tool, or P3ARRT) to rank the relative public health impact of pathogen-produce commodity combinations, based on explicit data-driven criteria. To identify candidate pathogen-commodity pairs, a database was created that included all published reports of fresh produce-associated outbreaks in the United States. A total risk score was calculated for each pathogen-commodity pair as the summation of nine criteria scores multiplied by the respective criteria weighting. A total of 53 pathogen-produce commodity pairs were included in the risk ranking, and based on scenario and sensitivity analyses, enterohemorrhagic E. coli in leafy greens consistently ranked first, followed by Salmonella spp. in tomatoes, and Salmonella spp. in leafy greens. The P3ARRT model provides a systematic, transparent, and customizable tool with which to prioritize produce pathogen-commodity pairs for further, more rigorous risk assessment modeling and evaluation efforts. The tool is available to the public at www.FoodRisk.org.}, number={12}, journal={FOOD CONTROL}, author={Anderson, Maren and Jaykus, Lee-Ann and Beaulieu, Steve and Dennis, Sherri}, year={2011}, month={Dec}, pages={1865–1872} }
 @misc{tirado_clarke_jaykus_mcquatters-gollop_franke_2010, title={Climate change and food safety: A review}, volume={43}, ISSN={["1873-7145"]}, DOI={10.1016/j.foodres.2010.07.003}, abstractNote={Climate change and variability may have an impact on the occurrence of food safety hazards at various stages of the food chain, from primary production through to consumption. There are multiple pathways through which climate related factors may impact food safety including: changes in temperature and precipitation patterns, increased frequency and intensity of extreme weather events, ocean warming and acidification, and changes in contaminants' transport pathways among others. Climate change may also affect socio-economic aspects related to food systems such as agriculture, animal production, global trade, demographics and human behaviour which all influence food safety. This paper reviews the potential impacts of predicted changes in climate on food contamination and food safety at various stages of the food chain and identifies adaptation strategies and research priorities to address food safety implications of climate change. The paper concludes that there is a need for inter- sectoral and international cooperation to better understand the changing food safety situation and in developing and implementing adaptation strategies to address emerging risks associated with climate change.}, number={7}, journal={FOOD RESEARCH INTERNATIONAL}, author={Tirado, M. C. and Clarke, R. and Jaykus, L. A. and McQuatters-Gollop, A. and Franke, J. M.}, year={2010}, month={Aug}, pages={1745–1765} }
 @article{drake_whitney_levine_depaola_jaykus_2010, title={Correlation of Mannitol Fermentation with Virulence-Associated Genotypic Characteristics inVibrio vulnificusIsolates from Oysters and Water Samples in the Gulf of Mexico}, volume={7}, ISSN={1535-3141 1556-7125}, url={http://dx.doi.org/10.1089/fpd.2009.0362}, DOI={10.1089/fpd.2009.0362}, abstractNote={Vibrio vulnificus strains (n = 469) isolated from the Gulf of Mexico oysters and waters over a period of 2 years were subjected to phenotypic and genotypic characterizations. Of the strains that could be definitively genotyped (n = 465), 58% were classified as genotype A, 29% as genotype B, and 13% as genotype A/B by 16S rRNA genotyping. When the same strain bank was characterized by virulence-correlated gene (vcg) typing, 65% were genotype E while 35% were genotype C. Further analysis focusing on strains falling into typical genotype categories (i.e., 16S rRNA types A or B, excluding type A/B strains) showed a high degree of concordance (93%) when comparing the two genotyping methods. d-Mannitol fermentation was also predictive of genotype, with an 86% agreement between 16S rRNA genotype and mannitol fermentation patterns, and an 85% agreement between vcg genotype and mannitol fermentation patterns. d-Mannitol fermentation should be considered as a simple and less expensive alternative to screen V. vulnificus isolates for virulence potential, particularly when analyzing large strain banks.}, number={1}, journal={Foodborne Pathogens and Disease}, publisher={Mary Ann Liebert Inc}, author={Drake, Stephenie L. and Whitney, Brooke and Levine, Jay F. and DePaola, Angelo and Jaykus, Lee-Ann}, year={2010}, month={Jan}, pages={97–101} }
 @article{björnsdóttir-butler_bolton_jaykus_mcclellan-green_green_2010, title={Development of molecular-based methods for determination of high histamine producing bacteria in fish}, volume={139}, ISSN={0168-1605}, url={http://dx.doi.org/10.1016/j.ijfoodmicro.2010.03.017}, DOI={10.1016/j.ijfoodmicro.2010.03.017}, abstractNote={Histamine (or scombroid) fish poisoning is a significant cause of food borne disease in the United States. In this study, we describe the development of a molecular-based technique which uses digoxigenin (DIG) labeled DNA probes for the detection of Gram negative bacteria producing high amounts of histamine (> 1000 ppm). A cocktail of PCR amplification fragments corresponding to a 709 bp fragment of the histidine decarboxylase (hdc) gene of four high producing bacteria (Morganella morganii, Enterobacter aerogenes, Raoultella planticola and Photobacterium damselae) was DIG-labeled and screened against a strain bank of 152 Gram negative bacteria isolated from scrombroid fish and their harvest environment. The probe cocktail reacted specifically (100%) with the high histamine producing strains but failed to react with low histamine producers and non-producers. To further evaluate the feasibility of the approach, fish homogenate inoculated with known concentrations of four high histamine producing bacterial strains was plated on modified Niven's medium (culture method) and trypticase soy agar supplemented with 2% NaCl (for colony lift hybridization). The colony lift hybridization counts did not differ significantly from the level of the initial inoculum (p > 0.05), while the modified Niven's counts were significantly lower (p < 0.05) than either inoculum or colony lift counts. The use of digoxigenin (DIG) labeled DNA probes with colony lift hybridization shows promise for accurate and specific enumeration of histamine producing bacteria in scombroid fish.}, number={3}, journal={International Journal of Food Microbiology}, publisher={Elsevier BV}, author={Björnsdóttir-Butler, Kristin and Bolton, Gregory E. and Jaykus, Lee-Ann and McClellan-Green, Patricia D. and Green, David P.}, year={2010}, month={May}, pages={161–167} }
 @article{liu_yuen_hsiao_jaykus_moe_2010, title={Effectiveness of Liquid Soap and Hand Sanitizer against Norwalk Virus on Contaminated Hands}, volume={76}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.01729-09}, abstractNote={ABSTRACT Disinfection is an essential measure for interrupting human norovirus (HuNoV) transmission, but it is difficult to evaluate the efficacy of disinfectants due to the absence of a practicable cell culture system for these viruses. The purpose of this study was to screen sodium hypochlorite and ethanol for efficacy against Norwalk virus (NV) and expand the studies to evaluate the efficacy of antibacterial liquid soap and alcohol-based hand sanitizer for the inactivation of NV on human finger pads. Samples were tested by real-time reverse transcription-quantitative PCR (RT-qPCR) both with and without a prior RNase treatment. In suspension assay, sodium hypochlorite concentrations of ≥160 ppm effectively eliminated RT-qPCR detection signal, while ethanol, regardless of concentration, was relatively ineffective, giving at most a 0.5 log 10 reduction in genomic copies of NV cDNA. Using the American Society for Testing and Materials (ASTM) standard finger pad method and a modification thereof (with rubbing), we observed the greatest reduction in genomic copies of NV cDNA with the antibacterial liquid soap treatment (0.67 to 1.20 log 10 reduction) and water rinse only (0.58 to 1.58 log 10 reduction). The alcohol-based hand sanitizer was relatively ineffective, reducing the genomic copies of NV cDNA by only 0.14 to 0.34 log 10 compared to baseline. Although the concentrations of genomic copies of NV cDNA were consistently lower on finger pad eluates pretreated with RNase compared to those without prior RNase treatment, these differences were not statistically significant. Despite the promise of alcohol-based sanitizers for the control of pathogen transmission, they may be relatively ineffective against the HuNoV, reinforcing the need to develop and evaluate new products against this important group of viruses.}, number={2}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Liu, Pengbo and Yuen, Yvonne and Hsiao, Hui-Mien and Jaykus, Lee-Ann and Moe, Christine}, year={2010}, month={Jan}, pages={394–399} }
 @article{liu_hsiao_jaykus_moe_2010, title={Quantification of Norwalk Virus Inocula: Comparison of Endpoint Titration and Real-Time Reverse Transcription-PCR Methods}, volume={82}, ISSN={["1096-9071"]}, DOI={10.1002/jmv.21851}, abstractNote={Human noroviruses (NoV) are the leading cause of epidemic acute gastroenteritis. In order to fully characterize features such as persistence and infectious dose, precise quantification of virus concentration is necessary. The purpose of this study was to compare two methods [endpoint titration RT-PCR and quantitative RT-PCR (RT-qPCR)] with respect to quantification of Norwalk virus (NV) in inocula made from purified stock suspensions of human fecal specimens. A full-length NV RNA transcript was developed to facilitate quantification using RT-qPCR and provided log linear detection in the range of 49–4.9 × 104 genome equivalent copies (GEC) per reaction. Endpoint titration RT-PCR was used to estimate PCR detection units, and RT-qPCR was used to estimate genome copies in two NV inocula (8fIIa and 8fIIb) used in previous human challenge studies. Overall, RT-qPCR was 1.1–1.6 log10 more sensitive (lower detection limit) than endpoint titration RT-PCR when the same RNA release method, PCR primers and thermocycle program were used. These findings have important implications for many experimental interpretations, not the least of which is estimating the median infectious dose in human challenge studies. J. Med. Virol. 82:1612–1616, 2010. © 2010 Wiley-Liss, Inc.}, number={9}, journal={JOURNAL OF MEDICAL VIROLOGY}, author={Liu, Pengbo and Hsiao, Hui-Mien and Jaykus, Lee-Ann and Moe, Christine}, year={2010}, month={Sep}, pages={1612–1616} }
 @article{dwivedi_smiley_jaykus_2010, title={Selection and characterization of DNA aptamers with binding selectivity to Campylobacter jejuni using whole-cell SELEX}, volume={87}, ISSN={["1432-0614"]}, DOI={10.1007/s00253-010-2728-7}, number={6}, journal={APPLIED MICROBIOLOGY AND BIOTECHNOLOGY}, author={Dwivedi, Hari P. and Smiley, R. Derike and Jaykus, Lee-Ann}, year={2010}, month={Aug}, pages={2323–2334} }
 @article{bjornsdottir_bolton_mcclellan-green_jaykus_green_2009, title={Detection of Gram-Negative Histamine-Producing Bacteria in Fish: A Comparative Study}, volume={72}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-72.9.1987}, abstractNote={Poisoning due to ingestion of foods with elevated levels of biogenic amines (histamine, putrescine, cadaverine, and tyramine) is well documented. Histamine fish poisoning largely is due to growth of naturally occurring bacteria associated with scombroid fish species. A rapid and reliable method is needed to screen for the presence of histamine-forming bacteria in fish. This study included a comparison of three methods for the detection of histamine-producing bacteria. A total of 152 histamine-producing and non-histamine-producing bacteria from multiple sources were screened using a modified Niven's agar method, a potentiometric method, and a PCR-based assay targeting a 709-bp fragment of the histidine decarboxylase gene. Histamine production by bacterial isolates was confirmed by high-performance liquid chromatography (HPLC). Bacterial strains were categorized as producing high amounts of histamine, low amounts of histamine, or no histamine. Of the 152 strains tested, 128 (84%) were positive with the Niven's agar method, 73 (48%) were positive with the potentiometric technique, and 74 (49%) were positive with the PCR assay. Overall, a 38% false-positive rate was observed with the modified Niven's agar method, although this method detected both low-histamine and high-histamine strains. There was a high degree of concordance (> 99%) between results of the potentiometric and PCR methods, but neither of these methods detected low-histamine bacteria. These observations support the need for a simple and straightforward yet sensitive method for detecting histamine-producing bacteria in seafood and environmental samples.}, number={9}, journal={JOURNAL OF FOOD PROTECTION}, author={Bjornsdottir, Kristin and Bolton, Gregory E. and McClellan-Green, Patricia D. and Jaykus, Lee-Ann and Green, David P.}, year={2009}, month={Sep}, pages={1987–1991} }
 @article{rawsthorne_phister_jaykus_2009, title={Development of a Fluorescent In Situ Method for Visualization of Enteric Viruses}, volume={75}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.01986-09}, abstractNote={ABSTRACT Studying the interactions between enteric pathogens and their environment is important to improving our understanding of their persistence and transmission. However, this remains challenging in large part because of difficulties associated with tracking pathogens in their natural environment(s). In this study, we report a fluorescent labeling strategy which was applied to murine norovirus (MNV-1), a human norovirus surrogate, and hepatitis A virus (HAV). Specifically, streptavidin-labeled Quantum dots (Q-Dots) were bound to biotinylated capsids of MNV-1 and HAV (bio-MNV-1 and bio-HAV); the process was confirmed by using a sandwich-type approach in which streptavidin-bound plates were reacted with biotinylated virus followed by a secondary binding to Q-Dots with an emission range of 635 to 675 nm (Q-Dots 655). The assay demonstrated a relative fluorescence of 528 ± 48.1 and 112 ± 8.6 for bio-MNV-1 and control MNV-1, respectively. The biotinylation process did not impact virus infectivity, nor did it interfere with the interactions between the virus and host cells or model produce items. Using fluorescent microscopy, it was possible to visualize both bio-HAV and bio-MNV-1 attached to the surfaces of permissive mammalian cells and green onion tissue. The method provides a powerful tool for the labeling and detection of enteric viruses (and their surrogates) which can be used to track virus behavior in situ.}, number={24}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Rawsthorne, Helen and Phister, Trevor G. and Jaykus, Lee-Ann}, year={2009}, month={Dec}, pages={7822–7827} }
 @article{newsome_tran_paoli_jaykus_tompkin_miliotis_ruthman_hartnett_busta_petersen_et al._2009, title={Development of a Risk-Ranking Framework to Evaluate Potential High-Threat Microorganisms, Toxins, and Chemicals in Food}, volume={74}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2008.01042.x}, abstractNote={Through a cooperative agreement with the U.S. Food and Drug Administration, the Institute of Food Technologists developed a risk-ranking framework prototype to enable comparison of microbiological and chemical hazards in foods and to assist policy makers, risk managers, risk analysts, and others in determining the relative public health impact of specific hazard-food combinations. The prototype is a bottom-up system based on assumptions that incorporate expert opinion/insight with a number of exposure and hazard-related risk criteria variables, which are propagated forward with food intake data to produce risk-ranking determinations. The prototype produces a semi-quantitative comparative assessment of food safety hazards and the impacts of hazard control measures. For a specific hazard-food combination the prototype can produce a single metric: a final risk value expressed as annual pseudo-disability adjusted life years (pDALY). The pDALY is a harmonization of the very different dose-response relationships observed for chemicals and microbes. The prototype was developed on 2 platforms, a web-based user interface and an Analytica(R) model (Lumina Decision Systems, Los Gatos, Calif., U.S.A.). Comprising visual basic language, the web-based platform facilitates data input and allows use concurrently from multiple locations. The Analytica model facilitates visualization of the logic flow, interrelationship of input and output variables, and calculations/algorithms comprising the prototype. A variety of sortable risk-ranking reports and summary information can be generated for hazard-food pairs, showing hazard and dose-response assumptions and data, per capita consumption by population group, and annual p-DALY.}, number={2}, journal={JOURNAL OF FOOD SCIENCE}, author={Newsome, R. and Tran, N. and Paoli, G. M. and Jaykus, L. A. and Tompkin, B. and Miliotis, M. and Ruthman, T. and Hartnett, E. and Busta, F. F. and Petersen, B. and et al.}, year={2009}, month={Mar}, pages={R39–R45} }
 @book{food-borne microbes: shaping the host ecosystem_2009, ISBN={9781555814052}, DOI={10.1128/9781555815479}, publisher={Washington, D.C.: ASM Press}, year={2009} }
 @article{kim_bang_drake_hanson_jaykus_2009, title={Impact of Storage Temperature and Product pH on the Survival of Listeria monocytogenes in Vacuum-Packaged Souse}, volume={72}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-72.3.637}, abstractNote={Souse is a fully cooked, ready-to-eat gelled pork product. There is a zero-tolerance policy for Listeria monocytogenes in ready-to-eat meat products. The survival and/or growth of L. monocytogenes in souse is unknown. The effectiveness of three different souse formulations (pH 4.3, 4.7, and 5.1) for controlling the growth of L. monocytogenes at two refrigerated storage temperatures (5 and 10 degrees C) was evaluated. All products were vacuum packaged. Uninoculated product was prepared as the control, and other products were artificially surface contaminated with a three-strain cocktail of L. monocytogenes (10(6) CFU/ cm2). Microbial counts were obtained on selective and nonselective media twice weekly through 8 weeks of storage. Souse did not support the growth of L. monocytogenes regardless of product formulation or storage temperature. At 5 degrees C, D-values for products with pH values of 4.7 and 5.1 were not different, but survival of L. monocytogenes in product with a lower pH (4.3) was decreased compared with survival in products with higher pH values (P < 0.05). Survival of L. monocytogenes was not impacted by storage temperatures (P > 0.05). Consumer acceptability (n = 75 souse consumers) of pH 4.3 products was not different from that for (typical) pH 4.7 products (P > 0.05). These results indicate that conventionally produced souse does not support the growth of L. monocytogenes and that inactivation of the organism is more likely in products formulated at a lower pH (< or = 4.3) without affecting consumer acceptance.}, number={3}, journal={JOURNAL OF FOOD PROTECTION}, author={Kim, M. K. and Bang, W. and Drake, M. A. and Hanson, D. J. and Jaykus, L. A.}, year={2009}, month={Mar}, pages={637–643} }
 @article{heldt_gurgel_jaykus_carbonell_2009, title={Influence of Peptide Ligand Surface Density and Ethylene Oxide Spacer Arm on the Capture of Porcine Parvovirus}, volume={25}, ISSN={["1520-6033"]}, DOI={10.1002/btpr.236}, abstractNote={In previous work, we identified two trimeric peptide ligands (designated WRW and KYY), which bound specifically to porcine parvovirus (PPV) and demonstrated their ability to capture and remove the virus from solutions containing 7.5% human blood plasma. This article examines the influences of peptide density and the presence of an ethylene oxide spacer arm on the efficiency of virus capture using these two ligands. The WRW peptide bound the most virus from plasma solutions at the lowest peptide density tested (0.008 mmol/g dry resin), and binding was enhanced by the presence of the spacer arm. On the other hand, the KYY peptide bound the most viruses at the same low peptide density, but it performed better in the absence of the spacer arm. Of the two, the binding efficiency of the WRW peptide was more sensitive to peptide density and spacer arm presence. These results indicate that low peptide densities enhance binding selectivity, facilitating specific peptide-virus binding even in the presence of plasma proteins which can theoretically bind nonspecifically. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009}, number={5}, journal={BIOTECHNOLOGY PROGRESS}, author={Heldt, Caryn L. and Gurgel, Patrick V. and Jaykus, Lee-Ann and Carbonell, Ruben G.}, year={2009}, pages={1411–1418} }
 @article{malek_barzilay_kramer_camp_jaykus_escudero‐abarca_derrick_white_gerba_higgins_et al._2009, title={Outbreak of Norovirus Infection among River Rafters Associated with Packaged Delicatessen Meat, Grand Canyon, 2005}, volume={48}, ISSN={1058-4838 1537-6591}, url={http://dx.doi.org/10.1086/594118}, DOI={10.1086/594118}, abstractNote={Background. Norovirus is often transmitted by infected food handlers at the point of service, whereas reports of food contamination before wholesale distribution are rare. In September 2005, we investigated reports of gastroenteritis among rafters who went on unrelated trips on the Colorado River. Methods. We surveyed all companies that launched rafting trips during the period from 14 August through 19 September 2005 to identify trips in which ⩾3 rafters became ill. We conducted a case-control study. Case patients were persons who experienced diarrhea or vomiting that commenced ⩽72 h after the trip launch; control subjects were persons who did not become ill ⩽72 h after launch. We tested stool samples and food specimens for norovirus. We performed a traceback investigation of the suspected food vehicle and inspected the implicated processing plant. Results. Three or more rafters developed gastroenteritis during 13 (14%) of 91 trips, for a total of 137 ill persons. Of the 57 case patients who became ill ⩽72 h after trip launch, 55 (96%) reported eating delicatessen meat, compared with 75 (79%) of 95 control subjects (odds ratio, 7.3; 95% confidence interval, 1.7–66.7). All delicatessen meat eaten by case patients came from 1 batch purchased from 1 processing plant and had been sliced, vacuum-packed, and frozen (temperature, −23°C) for 7–28 days. An employee sliced this batch with bare hands 1 day after recovery from gastroenteritis. Identical norovirus sequences were identified in stool specimens obtained from rafters on 3 different trips; 2 of 5 meat packages also tested positive for norovirus by reverse-transcriptase polymerase chain reaction and DNA hybridization. Conclusions. Food handlers can contaminate ready-to-eat meats with norovirus during processing. Meat-processing practices should include specific measures to prevent contamination with enteric viruses and subsequent widespread outbreaks.}, number={1}, journal={Clinical Infectious Diseases}, publisher={Oxford University Press (OUP)}, author={Malek, Mark and Barzilay, Ezra and Kramer, Adam and Camp, Brendan and Jaykus, Lee‐Ann and Escudero‐Abarca, Blanca and Derrick, Greg and White, Patricia and Gerba, Charles and Higgins, Charles and et al.}, year={2009}, month={Jan}, pages={31–37} }
 @article{rawsthorne_dock_jaykus_2009, title={PCR-Based Method Using Propidium Monoazide To Distinguish Viable from Nonviable Bacillus subtilis Spores}, volume={75}, ISSN={["0099-2240"]}, DOI={10.1128/AEM.02524-08}, abstractNote={ABSTRACT This paper describes a molecular-based method which is able to discriminate between viable and inactivated Bacillus subtilis spores by utilizing the DNA-intercalating dye propidium monoazide. The approach should be valuable in our attempt to employ molecular methods to streamline the evaluation of process validation using bacterial endospores.}, number={9}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Rawsthorne, H. and Dock, C. N. and Jaykus, L. A.}, year={2009}, month={May}, pages={2936–2939} }
 @article{liu_chien_papafragkou_hsiao_jaykus_moe_2009, title={Persistence of Human Noroviruses on Food Preparation Surfaces and Human Hands}, volume={1}, ISSN={["1867-0342"]}, DOI={10.1007/s12560-009-9019-4}, number={3-4}, journal={FOOD AND ENVIRONMENTAL VIROLOGY}, author={Liu, Pengbo and Chien, Yu-Wen and Papafragkou, Efstathia and Hsiao, Hui-Mien and Jaykus, Lee-Ann and Moe, Christine}, year={2009}, month={Dec}, pages={141–147} }
 @article{mokhtari_jaykus_2009, title={Quantitative exposure model for the transmission of norovirus in retail food preparation}, volume={133}, ISSN={["1879-3460"]}, DOI={10.1016/j.ijfoodmicro.2009.04.021}, abstractNote={It is widely recognized that the human noroviruses (HuNoV) are responsible for a large proportion of the world's foodborne disease burden. These viruses are transmitted by human fecal contamination and frequently make their way into foods because of poor personal hygiene of infected food handlers. This paper describes a probabilistic exposure assessment which models the dynamics of the transmission of HuNoV in the retail food preparation environment. Key inputs included degree of fecal shedding, hand hygiene behaviors, efficacy of virus removal and/or inactivation, and transferability of virus between surfaces. The model has a temporal dimension allowing contamination to be estimated as a function of time over the simulation period. Sensitivity and what-if scenario analyses were applied to identify the most important model inputs and evaluate potential mitigation strategies. The key inputs affecting estimates of the number of infectious viruses present in contaminated food servings, given the current model structure and assumptions, were as follows: mass of feces on hands (mFH), concentration of virus in feces (nvCF), number of bathroom visits, degree of gloving compliance (pWG), hand-washing efficiency (HWeff), and hand-washing compliance (pHW). The model suggests that gloving and hand-washing compliance are most effective in controlling contamination of food products when practiced simultaneously. Moreover, the bathroom environment was identified as a major reservoir of HuNoV, even in the absence of an ill individual on site. This mathematical approach to modeling the transmission of gastrointestinal viruses should facilitate comparison of potential mitigations aimed at reducing the transmission of foodborne viruses.}, number={1-2}, journal={INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY}, author={Mokhtari, Amirhossein and Jaykus, Lee-Ann}, year={2009}, month={Jul}, pages={38–47} }
 @misc{brehm-stecher_young_jaykus_tortorello_2009, title={Sample Preparation: The Forgotten Beginning}, volume={72}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x-72.8.1774}, abstractNote={Advances in molecular technologies and automated instrumentation have provided many opportunities for improved detection and identification of microorganisms; however, the upstream sample preparation steps needed to apply these advances to foods have not been adequately researched or developed. Thus, the extent to which these advances have improved food microbiology has been limited. The purpose of this review is to present the current state of sample preparation, to identify knowledge gaps and opportunities for improvement, and to recognize the need to support greater research and development efforts on preparative methods in food microbiology. The discussion focuses on the need to push technological developments toward methods that do not rely on enrichment culture. Among the four functional components of microbiological analysis (i.e., sampling, separation, concentration, detection), the separation and concentration components need to be researched more extensively to achieve rapid, direct, and quantitative methods. The usefulness of borrowing concepts of separation and concentration from other disciplines and the need to regard the microorganism as a physicochemical analyte that may be directly extracted from the food matrix are discussed. The development of next-generation systems that holistically integrate sample preparation with rapid, automated detection will require interdisciplinary collaboration and substantially increased funding.}, number={8}, journal={JOURNAL OF FOOD PROTECTION}, author={Brehm-Stecher, Byron and Young, Crarles and Jaykus, Lee-Ann and Tortorello, Mary Lou}, year={2009}, month={Aug}, pages={1774–1789} }
 @article{joshi_janagama_dwivedi_kumar_jaykus_schefers_sreevatsan_2009, title={Selection, characterization, and application of DNA aptamers for the capture and detection of Salmonella enterica serovars}, volume={23}, ISSN={["0890-8508"]}, DOI={10.1016/j.mcp.2008.10.006}, abstractNote={Sensitive and specific pre-analytical sample processing methods are needed to enhance our ability to detect and quantify food borne pathogens from complex food and environmental samples. In this study, DNA aptamers were selected and evaluated for the capture and detection of Salmonella enterica serovar. Typhimurium. A total of 66 candidate sequences were enriched against S. Typhimurium outer membrane proteins (OMPs) with counter-selection against Escherichia coli OMPs and lipopolysaccharides (LPS). Specificity of the selected aptamers was evaluated by gel-shift analysis against S. Typhimurium OMP. Five Salmonella-specific aptamer candidates were selected for further characterization. A dilution-to-extinction capture protocol using pure cultures of S. Typhimurium further narrowed the field to two candidates (aptamers 33 and 45) which showed low-end detection limits of 10-40CFU. DNase protection assays applied to these aptamers confirmed sequence-specific binding to S. Typhimurium OMP preparations, while South-Western blot analysis combined with mass spectrometry identified putative membrane proteins as targets for aptamer binding. Aptamer 33 was bound to magnetic beads and used for the capture of S. Typhimurium seeded into whole carcass chicken rinse samples, followed by detection using quantitative real-time RT-PCR. In a pull-down assay format, detection limits were 10(1)-10(2)CFU S. Typhimurium/9mL rinsate, while in a recirculation format, detection limits were 10(2)-10(3)CFU/25mL rinsate. Reproducible detection at <10(1)S. typhimurium CFU/g was also achieved in spike-and-recovery experiments using bovine feces. The pull-down analysis using aptamer 33 was validated on 3 naturally infected chicken litter samples confirming their applicability in the field. This study demonstrates the applicability of Salmonella specific aptamers for pre-analytical sample processing as applied to food and environmental sample matrices.}, number={1}, journal={MOLECULAR AND CELLULAR PROBES}, author={Joshi, Raghavendra and Janagama, Harish and Dwivedi, Hari P. and Kumar, T. M. A. Senthil and Jaykus, Lee-Ann and Schefers, Jeremy and Sreevatsan, Srinand}, year={2009}, month={Feb}, pages={20–28} }
 @article{gonzalez-escalona_martinez-urtaza_romero_espejo_jaykus_depaola_2008, title={Determination of molecular phylogenetics of Vibrio parahaemolyticus strains by multilocus sequence typing}, volume={190}, ISSN={["1098-5530"]}, DOI={10.1128/JB.01808-07}, abstractNote={ABSTRACT Vibrio parahaemolyticus is an important human pathogen whose transmission is associated with the consumption of contaminated seafood. There is a growing public health concern due to the emergence of a pandemic strain causing severe outbreaks worldwide. Many questions remain unanswered regarding the evolution and population structure of V. parahaemolyticus . In this work, we describe a multilocus sequence typing (MLST) scheme for V. parahaemolyticus based on the internal fragment sequences of seven housekeeping genes. This MLST scheme was applied to 100 V. parahaemolyticus strains isolated from geographically diverse clinical ( n = 37) and environmental ( n = 63) sources. The sequences obtained from this work were deposited and are available in a public database ( http://pubmlst.org/vparahaemolyticus ). Sixty-two unique sequence types were identified, and most (50) were represented by a single isolate, suggesting a high level of genetic diversity. Three major clonal complexes were identified by eBURST analysis. Separate clonal complexes were observed for V. parahaemolyticus isolates originating from the Pacific and Gulf coasts of the United States, while a third clonal complex consisted of strains belonging to the pandemic clonal complex with worldwide distribution. The data reported in this study indicate that V. parahaemolyticus is genetically diverse with a semiclonal population structure and an epidemic structure similar to that of Vibrio cholerae . Genetic diversity in V. parahaemolyticus appears to be driven primarily by frequent recombination rather than mutation, with recombination ratios estimated at 2.5:1 and 8.8:1 by allele and site, respectively. Application of this MLST scheme to more V. parahaemolyticus strains and by different laboratories will facilitate production of a global picture of the epidemiology and evolution of this pathogen.}, number={8}, journal={JOURNAL OF BACTERIOLOGY}, author={Gonzalez-Escalona, Narjol and Martinez-Urtaza, Jaime and Romero, Jaime and Espejo, Romilio T. and Jaykus, Lee-Ann and DePaola, Angelo}, year={2008}, month={Apr}, pages={2831–2840} }
 @article{melody_senevirathne_janes_jaykus_supan_2008, title={Effectiveness of icing as a postharvest treatment for control of Vibrio vulnificus and Vibrio parahaemolyticus in the eastern oyster (Crassostrea virginica)}, volume={71}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-71.7.1475}, abstractNote={The focus of this research was to investigate the efficacy of icing as a postharvest treatment for reduction of the levels of Vibrio vulnificus and Vibrio parahaemolyticus in commercial quantities of shellstock oysters. The experiments were conducted in June and August of 2006 and consisted of the following treatments: (i) on-board icing immediately after harvest; (ii) dockside icing approximately 1 to 2 h prior to shipment; and (iii) no icing (control). Changes in the levels of pathogenic Vibrio spp. during wholesale and retail handling for 2 weeks postharvest were also monitored. On-board icing achieved temperature reductions in all sacks in accordance with the National Shellfish Sanitation Program standard, but dockside icing did not meet this standard. Based on one-way analysis of variance, the only statistically significant relationship between Vibrio levels and treatment occurred for samples harvested in August; in this case, the levels of V. vulnificus in the noniced oysters were significantly higher (P < 0.05) than were the levels in the samples iced on-board. When analyzing counts over the 14-day storage period, using factorial analysis, there were statistically significant differences in V. vulnificus and V. parahaemolyticus levels by sample date and/or treatment (P < 0.05), but these relationships were not consistent. Treated (iced) oysters had significantly higher gaping (approximately 20%) after 1 week in cold storage than did noniced oysters (approximately 10%) and gaping increased significantly by day 14 of commercial storage. On-board and dockside icing did not predictably reduce the levels of V. vulnificus or V. parahaemolyticus in oysters, and icing negatively impacted oyster survival during subsequent cold storage.}, number={7}, journal={JOURNAL OF FOOD PROTECTION}, author={Melody, Kevin and Senevirathne, Reshani and Janes, Marlene and Jaykus, Lee Ann and Supan, John}, year={2008}, month={Jul}, pages={1475–1480} }
 @article{heldt_gurgel_jaykus_carbonell_2008, title={Identification of trimeric peptides that bind porcine parvovirus from mixtures containing human blood plasma}, volume={24}, ISSN={["1520-6033"]}, DOI={10.1021/bp070412c}, abstractNote={Virus contamination in human therapeutics is of growing concern as more therapeutic products from animal or human sources come into the market. All biopharmaceutical processes are required to have at least two distinct viral clearance steps to remove viruses. Most of these steps work well for enveloped viruses and large viruses, whether enveloped or not. That leaves a class of small non-enveloped viruses, like parvoviruses and hepatitis A, which are not easily removed by these typical steps. In this study, we report the identification of trimeric peptides that bind specifically to porcine parvovirus (PPV) and their potential use to remove this virus from process solutions. All of the trimeric peptides isolated completely removed all detectable PPV from buffer in the first nine column volumes, corresponding to a clearance of 4.5–5.5 log of infectious virus. When the virus was spiked into a more complex matrix consisting of 7.5% human blood plasma, one of the trimers, WRW, was able to remove all detectable PPV in the first three column volumes, after which human blood plasma began to interfere with the binding of the virus to the peptide resin. These trimer resins removed considerably more virus than weak ion exchange resins. The results of this work indicate that small peptide ligand resins have the potential to be used in virus removal processes where removal of contaminating virus is necessary to ensure product safety.}, number={3}, journal={BIOTECHNOLOGY PROGRESS}, author={Heldt, Caryn L. and Gurgel, Patrick V. and Jaykus, Lee-Ann and Carbonell, Ruben G.}, year={2008}, pages={554–560} }
 @article{macinga_sattar_jaykus_arbogast_2008, title={Improved inactivation of nonenveloped enteric viruses and their surrogates by a novel alcohol-based hand sanitizer}, volume={74}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.00487-08}, abstractNote={ABSTRACT Norovirus is the leading cause of food-related illness in the United States, and contamination of ready-to-eat items by food handlers poses a high risk for disease. This study reports the in vitro (suspension test) and in vivo (fingerpad protocol) assessments of a new ethanol-based hand sanitizer containing a synergistic blend of polyquaternium polymer and organic acid, which is active against viruses of public health importance, including norovirus. When tested in suspension, the test product reduced the infectivity of the nonenveloped viruses human rotavirus (HRV), poliovirus type 1 (PV-1), and the human norovirus (HNV) surrogates feline calicivirus (FCV) F-9 and murine norovirus type 1 (MNV-1) by greater than 3 log 10 after a 30-s exposure. In contrast, a benchmark alcohol-based hand sanitizer reduced only HRV by greater than 3 log 10 and none of the additional viruses by greater than 1.2 log 10 after the same exposure. In fingerpad experiments, the test product produced a 2.48 log 10 reduction of MNV-1 after a 30-s exposure, whereas a 75% ethanol control produced a 0.91 log 10 reduction. Additionally, the test product reduced the infectivity titers of adenovirus type 5 (ADV-5) and HRV by ≥3.16 log 10 and ≥4.32 log 10 , respectively, by the fingerpad assay within 15 s; and PV-1 was reduced by 2.98 log 10 in 30 s by the same method. Based on these results, we conclude that this new ethanol-based hand sanitizer is a promising option for reducing the transmission of enteric viruses, including norovirus, by food handlers and care providers.}, number={16}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Macinga, David R. and Sattar, Syed A. and Jaykus, Lee-Ann and Arbogast, James W.}, year={2008}, month={Aug}, pages={5047–5052} }
 @article{viazis_farkas_jaykus_2008, title={Inactivation of bacterial pathogens in human milk by high-pressure processing}, volume={71}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-71.1.109}, abstractNote={Low-temperature, long-time (LTLT) pasteurization assures the safety of banked human milk; however, heat can destroy important nutritional biomolecules. High-pressure processing (HPP) shows promise as an alternative for pasteurization of breast milk. The purpose of this study was to investigate the efficacy of HPP for inactivation of selected bacterial pathogens in human milk. Human milk was inoculated with one of five pathogens (10(8) to 10(9) CFU/ml), while 0.1% peptone solution solutions with the same levels of each organism were used as controls. The samples were subjected to 400 MPa at 21 to 31 degrees C for 0 to 50 min or to 62.5 degrees C for 0 to 30 min (capillary tube method) to simulate LTLT pasteurization. Tryptic soy agar and selective media were used for enumeration. Traditional thermal pasteurization resulted in inactivation (> 7 log) of all pathogens within 10 min. In human milk and in peptone solution, a 6-log reduction was achieved after 30 min of HPP for Staphylococcus aureus ATCC 6538. After 30 min, S. aureus ATCC 25923 was reduced by 8 log and 6 log in human milk and peptone solution, respectively. Treatments of 4 and 7 min resulted in an 8-log inactivation of Streptococcus agalactiae ATCC 12927 in human milk and peptone solution, respectively, while Listeria monocytogenes ATCC 19115 required 2 min for an 8-log inactivation in human milk. Escherichia coli ATCC 25922 was inactivated by 8 log after 10 min in peptone solution and by 6 log after 30 min in human milk. These data suggest that HPP may be a promising alternative for pasteurization of human milk. Further research should evaluate the efficacy of HPP in the inactivation of relevant viral pathogens.}, number={1}, journal={JOURNAL OF FOOD PROTECTION}, author={Viazis, S. and Farkas, B. E. and Jaykus, L. A.}, year={2008}, month={Jan}, pages={109–118} }
 @article{ailes_leon_jaykus_johnston_clayton_blanding_kleinbaum_backer_moe_2008, title={Microbial Concentrations on Fresh Produce Are Affected by Postharvest Processing, Importation, and Season}, volume={71}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-71.12.2389}, abstractNote={In the United States, the proportion of foodborne illness outbreaks associated with consumption of contaminated domestic and imported fresh fruits and vegetables (produce) has increased over the past several decades. To address this public health concern, the goal of this work was to identify and quantify factors associated with microbial contamination of produce in pre- and postharvest phases of the farm-to-fork continuum. From 2000 to 2003, we collected 923 samples of 14 types of produce (grown in the southern United States or in the northern border states of Mexico) from 15 farms and eight packing sheds located in the southern United States. To assess microbial quality, samples were enumerated for Escherichia coli, total aerobic bacteria, total coliforms, and total Enterococcus. Most produce types had significantly higher microbial concentrations when sampled at the packing shed than when sampled at the farm. In addition, we observed seasonal differences in the microbial concentrations on samples grown in the United States, with higher mean indicator concentrations detected in the fall (September, October, and November). We developed a predictive, multivariate logistic regression model to identify and quantify factors that were associated with detectable concentrations of E. coli contamination on produce. These factors included produce type (specifically, cabbage or cantaloupe), season of collection (harvested in the fall), and packing step (bin, box, conveyor belt, or turntable). These results can be used to identify specific mechanisms of produce contamination and propose interventions that may decrease the likelihood of produce-associated illness.}, number={12}, journal={JOURNAL OF FOOD PROTECTION}, author={Ailes, Elizabeth C. and Leon, Juan S. and Jaykus, Lee-Ann and Johnston, Lynette M. and Clayton, Haley A. and Blanding, Sarah and Kleinbaum, David G. and Backer, Lorraine C. and Moe, Christine L.}, year={2008}, month={Dec}, pages={2389–2397} }
 @article{papafragkou_plante_mattison_bidawid_karthikeyan_farber_jaykus_2008, title={Rapid and sensitive detection of hepatitis A virus in representative food matrices}, volume={147}, ISSN={["0166-0934"]}, DOI={10.1016/j.jviromet.2007.08.024}, abstractNote={Hepatitis A virus (HAV) is an important cause of foodborne disease worldwide. The detection of this virus in naturally contaminated food products is complicated by the absence of a reliable culture method, low levels of contamination, and the presence of matrix-associated compounds which inhibit molecular detection. In this study, we report a novel method to concentrate HAV from foods prior to the application of reverse transcription-PCR (RT-PCR) for detection. Specifically, we used cationically charged magnetic particles with an automated capture system (Pathatrix™) to concentrate the virus from 25 g samples of artificially contaminated lettuce, strawberries, green onions, deli-turkey, oysters, and cake with frosting. Detection limits varied according to the product but in most cases, the virus could be consistently detected at input levels corresponding to 102 PFU/25 g food sample. For some products, detection was possible at levels as low as 10−1 PFU/25 g. The assay was applied by a second independent laboratory and was also used to confirm viral contamination of produce items associated with a recent HAV outbreak. Parallel infectivity assays demonstrated that the cationically charged particles bound approximately 50% of the input virus. This is the first application of the automated magnetic capture technology to the concentration of viruses from foods, and it offers promise for facilitating the rapid detection of HAV from naturally contaminated products.}, number={1}, journal={JOURNAL OF VIROLOGICAL METHODS}, author={Papafragkou, Efstathia and Plante, Michelle and Mattison, Kirsten and Bidawid, Sabah and Karthikeyan, Kalavethi and Farber, Jeffrey M. and Jaykus, Lee-Ann}, year={2008}, month={Jan}, pages={177–187} }
 @article{gonzalez-escalona_jaykus_depaola_2007, title={Accurate identification of desired clones from 16S-23S rDNA spacer libraries using single PCR}, volume={360}, ISSN={["1096-0309"]}, DOI={10.1016/j.ab.2006.10.026}, number={1}, journal={ANALYTICAL BIOCHEMISTRY}, author={Gonzalez-Escalona, Narjol and Jaykus, Lee-Ann and DePaola, Angelo}, year={2007}, month={Jan}, pages={146–147} }
 @misc{drake_depaola_jaykus_2007, title={An overview of Vibrio vulnificus and Vibrio parahaemolyticus}, volume={6}, ISSN={["1541-4337"]}, DOI={10.1111/j.1541-4337.2007.00022.x}, abstractNote={ABSTRACT: The Vibrionaceae are environmentally ubiquitous to estuarine waters. Two species in particular, V. vulnificus and V. parahaemolyticus, are important human pathogens that are transmitted by the consumption of contaminated molluscan shellfish. This document provides a comprehensive review of the current state of knowledge about these important foodborne disease agents. Topics include the epidemiology of human disease; biotypes and virulence factors; cultural and molecular-based detection methods; phenotyping and genotyping approaches; microbial ecology; and candidate control strategies. Recent international risk assessment efforts are also described. The reader will gain an understanding of why these organisms pose a public health risk and how improving our understanding of their behavior in the environment and the host can aid in reducing that risk in the future.}, number={4}, journal={COMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY}, author={Drake, Stephenie L. and DePaola, Angelo and Jaykus, Lee-Ann}, year={2007}, month={Oct}, pages={120–144} }
 @article{gonzalez-escalona_whitney_jaykus_depaola_2007, title={Comparison of direct genome Restriction Enzyme analysis and pulsed-field gel electrophoresis for typing of Vibrio vulnificus and their correspondence with multilocus sequence typing data}, volume={73}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.00738-07}, abstractNote={ABSTRACT We compared the potential of direct genome restriction enzyme analysis (DGREA) and pulsed-field gel electrophoresis (PFGE) for discriminating Vibrio vulnificus isolates from clinical (23) and environmental (17) sources. The genotypes generated by both methodologies were compared to previous multilocus sequence typing (MLST) data. DGREA established clearer relationships among V. vulnificus strains and was more consistent with MLST than with PFGE. DGREA is a very promising tool for epidemiological and ecological studies of V. vulnificus .}, number={22}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Gonzalez-Escalona, Narjol and Whitney, Brooke and Jaykus, Lee-Ann and DePaola, Angelo}, year={2007}, month={Nov}, pages={7494–7500} }
 @article{hegde_leon-velarde_stam_jaykus_odumeru_2007, title={Evaluation of BBL CHROMagar Listeria agar for the isolation and identification of Listeria monocytogenes from food and environmental samples}, volume={68}, ISSN={["1872-8359"]}, DOI={10.1016/j.mimet.2006.06.011}, abstractNote={The performance of BBL CHROMagar Listeria chromogenic agar for the detection of Listeria monocytogenes was evaluated for its ability to isolate and identify L. monocytogenes from food and environmental samples. The medium was compared to non-chromogenic selective agars commonly used for Listeria isolation: Oxford, Modified Oxford, and PALCAM. BBL CHROMagar Listeria had a sensitivity of 99% and 100% for the detection of L. monocytogenes from 200 natural and artificially inoculated food samples, respectively, with a colony confirmation rate of 100%. The sensitivity of non-chromogenic selective media for the detection of L. monocytogenes from these same samples was 97-99% with colony confirmation rates of 65-67.5%. From 93 environmental samples, BBL CHROMagar Listeria agar results correlated 100% with a Listeria spp. visual immunoassay (TECRA) performed on these same samples and the USDA-FSIS standard culture method for the isolation of L. monocytogenes. From environmental samples, the L. monocytogenes confirmation rate was 100% for BBL CHROMagar Listeria as compared to 50% for conventional agars tested. On BBL CHROMagar Listeria, L. monocytogenes forms a translucent white precipitation zone (halo) surrounding blue-pigmented colonies of 2-3 mm in diameter, with an entire border. BBL CHROMagar Listeria offers a high degree of specificity for the confirmation of suspect L. monocytogenes colonies, whereas non-chromogenic selective agars evaluated were not differential for L. monocytogenes from other Listeria species.}, number={1}, journal={JOURNAL OF MICROBIOLOGICAL METHODS}, author={Hegde, Veena and Leon-Velarde, Carlos G. and Stam, Christina M. and Jaykus, Lee-Ann and Odumeru, Joseph A.}, year={2007}, month={Jan}, pages={82–87} }
 @article{brinley_stam_truong_coronel_kumar_simunovic_sandeep_cartwright_swartzel_jaykus_et al._2007, title={Feasibility of utilizing bioindicators for testing microbial inactivation in sweetpotato purees processed with a continuous-flow microwave system}, volume={72}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2007.00371.x}, abstractNote={ABSTRACT: Continuous-flow microwave heating has potential in aseptic processing of various food products, including purees from sweetpotatoes and other vegetables. Establishing the feasibility of a new processing technology for achieving commercial sterility requires evaluating microbial inactivation. This study aimed to assess the feasibility of using commercially available plastic pouches of bioindicators containing spores of Geobacillius stearothermophilus ATCC 7953 and Bacillus subtilis ATCC 35021 for evaluating the degree of microbial inactivation achieved in vegetable purees processed in a continuous-flow microwave heating unit. Sweetpotato puree seeded with the bioindicators was subjected to 3 levels of processing based on the fastest particles: undertarget process (F0 approximately 0.65), target process (F0 approximately 2.8), and overtarget process (F0 approximately 10.10). After initial experiments, we found it was necessary to engineer a setup with 2 removable tubes connected to the continuous-flow microwave system to facilitate the injection of indicators into the unit without interrupting the puree flow. Using this approach, 60% of the indicators injected into the system could be recovered postprocess. Spore survival after processing, as evaluated by use of growth indicator dyes and standard plating methods, verified inactivation of the spores in sweetpotato puree. The log reduction results for B. subtilis were equivalent to the predesigned degrees of sterilization (F0). This study presents the first report suggesting that bioindicators such as the flexible, food-grade plastic pouches can be used for microbial validation of commercial sterilization in aseptic processing of foods using a continuous-flow microwave system.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={Brinley, T. A. and Stam, C. N. and Truong, V. D. and Coronel, P. and Kumar, P. and Simunovic, J. and Sandeep, K. P. and Cartwright, G. D. and Swartzel, K. R. and Jaykus, L. A. and et al.}, year={2007}, pages={E235–E242} }
 @article{santos_d'souza_jaykus_ferket_sheldon_2007, title={Genotypes, serotypes, and antibiotic resistance profiles of Salmonella isolated from commercial North Carolina Turkey farms}, volume={70}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-70.6.1328}, abstractNote={This study was designed to determine the serotypes, genotypes, and antibiotic resistance (AbR) patterns of 42 Salmonella isolates recovered from either fecal or litter samples of 12 commercial turkey farms across two seasons (summer and winter) and two ages (3 and 19 weeks). Isolates were serotyped on the basis of the Kauffmann-White scheme. Genotyping was done by restriction digestion of cDNA (XbaI) and subsequent pulsed-field gel electrophoresis (PFGE). The AbR was determined with Sensititre susceptibility plates. Serovar Kentucky was the most prevalent serotype (26%), followed by Senftenberg (19%), Muenster (17%), Mbandaka (10%), Javiana (7%), Hadar (5%), Heidelberg (5%), 8,(20):nonmotile (5%), Agona (2%), Infantis (2%), and 4,12:r:-(2%). Serovars Kentucky, Heidelberg, Hadar, and 8,(20):nonmotile were isolated only from the 19-week-old bird samples, whereas Senftenberg and Muenster were isolated only from the young birds (3 weeks old). Isolates within any one serotype showed minor PFGE banding pattern differences, but dendogram analysis indicated that sequence variability between serotypes was more significant than within serotypes. Isolates were resistant to tetracycline (86%), sulfisoxazole (71%), streptomycin (64%), gentamicin (41%), ampicillin (36%), kanamycin (26%), sulfamethoxazole-trimethoprim (7%), nalidixic acid (5%), cefoxitin (2%), and ceftiofur (2%). One isolate (Muenster) was resistant to nine antibiotics (2%), and the others were resistant to six (7%), five (12%), four (10%), three (21%), two (24%), and one (10%) antibiotic. Only two isolates (5%) were susceptible to all antibiotics tested. The AbR patterns were affected by age; on average, strains recovered from young birds were resistant to more than four drugs compared with fewer than three in older birds (P < 0.05). This study showed that Salmonella enterica subsp. enterica serotypes, genotypes and AbR patterns were affected by bird age but not by season or farm.}, number={6}, journal={JOURNAL OF FOOD PROTECTION}, author={Santos, F. B. O. and D'Souza, D. H. and Jaykus, L. and Ferket, P. R. and Sheldon, B. W.}, year={2007}, month={Jun}, pages={1328–1333} }
 @article{cates_kosa_moore_jaykus_ten eyck_cowen_2007, title={Listeriosis prevention for older adults: Effective messages and delivery methods}, volume={33}, ISSN={["1521-0472"]}, DOI={10.1080/03601270701411023}, abstractNote={Individuals aged 60 years and older are at an increased risk for listeriosis and other foodborne illnesses. They can reduce their risk by following recommended food safety practices. A total of 8 focus groups were conducted to characterize older adults' food safety knowledge and practices, their impressions of educational materials on listeriosis prevention, barriers to adopting the recommended practices, and preferred delivery methods. Participants were not aware of listeriosis and recommended practices for listeriosis prevention. Adoption of the recommended practices was not widespread following exposure to the educational materials. This study identified the need to reach older adults with information on listeriosis prevention.}, number={7}, journal={EDUCATIONAL GERONTOLOGY}, author={Cates, Sheryl C. and Kosa, Katherine M. and Moore, Christina M. and Jaykus, Lee-Ann and Ten Eyck, Toby A. and Cowen, Peter}, year={2007}, pages={587–606} }
 @article{bang_drake_jaykus_2007, title={Recovery and detection of Vibrio vulnificus during cold storage}, volume={24}, ISSN={["1095-9998"]}, DOI={10.1016/j.fm.2006.12.002}, abstractNote={Different cultural techniques and molecular methods for the detection of Vibrio vulnificus during cold storage in a model broth system were compared. Two strains of V. vulnificus were grown to stationary phase and inoculated (10(6) CFU/mL) into tryptic soy broth with 2% sodium chloride (TSBN2) or artificial seawater (ASW), both pre-chilled to 5 degrees C. These were stored for 10 days, with sub-sampling conducted at time 0 and every 2 days thereafter. Each subsample was plated, by both pour and spread plate techniques, onto tryptic soy agar 2% sodium chloride (TSAN2) with or without catalase (400 or 600 U) or sodium pyruvate (80 or 160 mg) supplementation. Nucleic acids were extracted from subsamples and subjected to PCR and RT-PCR with hemolysin as the target. Higher recoveries of V. vulnificus were obtained with spread plating compared to pour plating (P<0.05). The addition of sodium pyruvate (80 mg) or catalase (400 U) significantly increased cell recovery (P<0.05). PCR amplification signals were stronger than RT-PCR signals at each timepoint, and results were generally consistent between TSAN2 and ASW for each strain. These results will aid in the design of optimum methods to recover and/or detect V. vulnificus cells subjected to sublethal stress that might be encountered in food processing and storage.}, number={6}, journal={FOOD MICROBIOLOGY}, author={Bang, W. and Drake, M. A. and Jaykus, L. A.}, year={2007}, month={Sep}, pages={664–670} }
 @article{vicari_mokhtari_morales_jaykus_frey_slenning_cowen_2007, title={Second-order modeling of variability and uncertainty in microbial hazard characterization}, volume={70}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-70.2.363}, abstractNote={This study describes an analytical framework that permits quantitative consideration of variability and uncertainty in microbial hazard characterization. Second-order modeling that used two-dimensional Monte Carlo simulation and stratification into homogeneous population subgroups was applied to integrate uncertainty and variability. Specifically, the bootstrap method was used to simulate sampling error due to the limited sample size in microbial dose-response modeling. A data set from human feeding trials with Campylobacter jejuni was fitted to the log-logistic dose-response model, and results from the analysis of FoodNet surveillance data provided further information on variability and uncertainty in Campylobacter susceptibility due to the effect of age. Results of our analyses indicate that uncertainty associated with dose-response modeling has a dominating influence on the analytical outcome. In contrast, inclusion of the age factor has a limited impact. While the advocacy of more closely modeling variability in hazard characterization is warranted, the characterization of key sources of uncertainties and their consistent propagation throughout a microbial risk assessment actually appear of greater importance.}, number={2}, journal={JOURNAL OF FOOD PROTECTION}, author={Vicari, Andrea S. and Mokhtari, Amirhossein and Morales, Roberta A. and Jaykus, Lee-Ann and Frey, H. Christopher and Slenning, Barrett D. and Cowen, Peter}, year={2007}, month={Feb}, pages={363–372} }
 @article{gonzalez-escalona_jaykus_depaola_2007, title={Typing of Vibrio vulnificus strains by variability in their 16S-23S rRNA Intergenic Spacer regions}, volume={4}, ISSN={["1556-7125"]}, DOI={10.1089/fpd.2007.0005}, abstractNote={Amplification of the 16S-23S rDNA spacer region (ISR1) is a simple and rapid procedure for subtyping bacteria, especially those with several ribosomal operons including Vibrio vulnificus. V. vulnificus contains nine ribosomal operons with four or five ISR1 classes that differ in size and sequence. In the present study, 47 V. vulnificus strains of both shellfish and clinical origin were subtyped by their ISR1 patterns using “universal” primers, which target conserved sequences located in the 16S and the 23S rRNA genes. Sixteen different ISR1 patterns were observed that were grouped into two major clusters. Most (21/27, 77.8%) clinical isolates examined in this study grouped into a single cluster containing ISR1 patterns I, V, XI, and XII and these were highly similar (75%). This cluster was restricted to strains carrying the type B 16S rDNA (rrs) sequence which has been associated with human illness in previous studies. The remaining cluster consisted primarily of shellfish isolates. The highest variability in the ISR1 patterns was observed among shellfish isolates. Sequence analysis of the ISR1 region of selected strains demonstrated that all of them possess five ISR1 classes, with two “conserved sequence blocks” at the 5′ and 3′ end of the ISR1. All of these strains carried at least one tRNA gene and different classes differed in their tRNA gene composition. Some of the same ISR1 classes differed in size mainly due to an insertion of 35 bp in either of the conserved sequence blocks. These results demonstrate the feasibility of the ISR1 technique for V. vulnificus subtyping and suggest that ISR1 patterns appear to be linked to rrs sequence types and perhaps with virulence.}, number={3}, journal={FOODBORNE PATHOGENS AND DISEASE}, author={Gonzalez-Escalona, Narjol and Jaykus, Lee-Ann and DePaola, Angelo}, year={2007}, pages={327–337} }
 @article{johnston_jaykus_moll_anciso_mora_moe_2006, title={A field study of the microbiological quality of fresh produce of domestic and Mexican origin}, volume={112}, ISSN={["1879-3460"]}, DOI={10.1016/j.ijfoodmicro.2006.05.002}, abstractNote={Produce is responsible for an increasingly larger proportion of foodborne disease outbreaks. In particular, the globalization of the food supply may introduce new food safety risks and allow widespread distribution of contaminated food, particularly produce. The objectives of this study were to: (i) compare the overall quality of domestic and Mexican produce throughout the packing process; (ii) examine changes in microbiological quality of both domestic and Mexican produce at each stage of production and processing; and (iii) evaluate the prevalence of select pathogens on fresh produce, including leafy green, herbs, melons, and vegetables. Furthermore, we also sought to characterize the antibiotic resistance profiles of Enterococcus faecium and Enterococcus faecalis strains isolated from fresh produce. A total of 466 produce and matching environmental swab samples was collected from various locations in packing sheds in the southern US from November 2002 through December 2003. These samples were assayed by enumerative tests for total aerobic bacteria (APC), total coliforms, total Enterococcus, and E. coli. Produce samples were also analyzed for the presence of Salmonella, Listeria monocytogenes, Shigella, and E. coli O157:H7. A total of 112 E. faecium and E. faecalis isolates were further screened for antibiotic resistance using a panel of seventeen antibiotics. Overall, the microbiological quality of fresh produce ranged from 4.0 to 7.9 log(10) CFU/g (APC); less than 1.0 log(10) to 4.5 log(10) CFU/g (coliforms); less than 1.0 log(10) to 4.0 log(10) CFU/g (E. coli); and less than 1.0 log(10) to 5.4 log(10) CFU/g (Enterococcus). No Salmonella, Shigella, or E. coli O157:H7 were detected from the 466 25-g produce samples tested. However, three domestic cabbage samples were found to be positive for L. monocytogenes. Of the Enterococcus isolates, E. faecium had a higher degree of resistance to antibiotics in general, while Enterococcus spp. isolated from Mexican produce had a higher degree of antibiotic resistance when compared to strains isolated from produce samples of domestic origin. Despite increased attention to the role of imported produce in foodborne disease, this study does not support the assumption that domestic produce is of higher microbial quality than Mexican produce.}, number={2}, journal={INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY}, author={Johnston, Lynette M. and Jaykus, Lee-Ann and Moll, Deborah and Anciso, Juan and Mora, Brenda and Moe, Christine L.}, year={2006}, month={Nov}, pages={83–95} }
 @article{mokhtari_frey_jaykus_2006, title={Application of classification and regression trees for sensitivity analysis of the Escherichia coli O157 : H7 food safety process risk model}, volume={69}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-69.3.609}, abstractNote={Microbial food safety process risk models are simplifications of the real world that help risk managers in their efforts to mitigate food safety risks. An important tool in these risk assessment endeavors is sensitivity analysis, a systematic method used to quantify the effect of changes in input variables on model outputs. In this study, a novel sensitivity analysis method called classification and regression trees was applied to safety risk assessment with the use of portions of the Slaughter Module and Preparation Module of the E. coli O157:H7 microbial food safety process risk as an example. Specifically, the classification and regression trees sensitivity analysis method was evaluated on the basis of its ability to address typical characteristics of microbial food safety process risk models such as nonlinearities, interaction, thresholds, and categorical inputs. Moreover, this method was evaluated with respect to identification of high exposure scenarios and corresponding key inputs and critical limits. The results from the classification and regression trees analysis applied to the Slaughter Module confirmed that the process of chilling carcasses is a critical control point. The method identified a cutoff value of a 2.2-log increase in the number of organisms during chilling as a critical value above which high levels of contamination would be expected. When classification and regression trees analysis was applied to the cooking effects part of the Preparation Module, cooking temperature was found to be the most sensitive input, with precooking treatment (i.e., raw product storage conditions) ranked second in importance. This case study demonstrates the capabilities of classification and regression trees analysis as an alternative to other statistically based sensitivity analysis methods, and one that can readily address specific characteristics that are common in microbial food safety process risk models.}, number={3}, journal={JOURNAL OF FOOD PROTECTION}, author={Mokhtari, A and Frey, HC and Jaykus, LA}, year={2006}, month={Mar}, pages={609–618} }
 @article{cates_morales_karns_jaykus_kosa_teneyck_moore_cowen_2006, title={Consumer knowledge, storage, and handling practices regarding Listeria in frankfurters and deli meats: Results of a web-based survey}, volume={69}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-69.7.1630}, abstractNote={Proper storage and handling of refrigerated ready-to-eat foods can help reduce the risk of listeriosis. A national Web-based survey was conducted to measure consumer awareness and knowledge of Listeria and to estimate the prevalence of the U.S. Department of Agriculture-recommended consumer storage and handling practices for frankfurters and deli meats. The demographic characteristics of consumers who are unaware of Listeria and who do not follow the recommended storage guidelines were also assessed. In addition, predictive models were developed to determine which consumers engage in risky storage practices. Less than half of the consumers surveyed were aware of Listeria, and most of those aware were unable to identify associated food vehicles. Awareness was lower among adults 60 years of age and older, an at-risk population for listeriosis, and individuals with relatively less education and lower incomes. Most households safely stored and prepared frankfurters. Most households stored unopened packages of vacuum-packed deli meats in the refrigerator within the U.S. Department of Agriculture-recommended storage guidelines (< or =14 days); however, many stored opened packages of vacuum-packed deli meats and freshly sliced deli meats for longer than the recommended time (< or =5 days). Men, more-educated individuals, and individuals living in metropolitan areas were more likely to engage in risky storage practices. This study identified the need to develop targeted educational initiatives on listeriosis prevention.}, number={7}, journal={JOURNAL OF FOOD PROTECTION}, author={Cates, Sheryl C. and Morales, Roberta A. and Karns, Shawn A. and Jaykus, Lee-Ann and Kosa, Katherine M. and Teneyck, Toby and Moore, Christina M. and Cowen, Peter}, year={2006}, month={Jul}, pages={1630–1639} }
 @article{yang_mokhtari_jaykus_morales_cates_cowen_2006, title={Consumer phase risk assessment for Listeria monocytogenes in deli meats}, volume={26}, DOI={10.1111/j.1539-6924.2006.00071.x}, number={1}, journal={Risk Analysis}, author={Yang, H. and Mokhtari, A. and Jaykus, L. A. and Morales, R. A. and Cates, S. C. and Cowen, P.}, year={2006}, pages={89–103} }
 @article{mokhtari_moore_yang_jaykus_morales_cates_cowen_2006, title={Consumer-phase Salmonella enterica serovar Enteritidis risk assessment for egg-containing food products}, volume={26}, ISSN={["1539-6924"]}, DOI={10.1111/j.1539-6924.2006.00759.x}, abstractNote={We describe a one-dimensional probabilistic model of the role of domestic food handling behaviors on salmonellosis risk associated with the consumption of eggs and egg-containing foods. Six categories of egg-containing foods were defined based on the amount of egg contained in the food, whether eggs are pooled, and the degree of cooking practiced by consumers. We used bootstrap simulation to quantify uncertainty in risk estimates due to sampling error, and sensitivity analysis to identify key sources of variability and uncertainty in the model. Because of typical model characteristics such as nonlinearity, interaction between inputs, thresholds, and saturation points, Sobol's method, a novel sensitivity analysis approach, was used to identify key sources of variability. Based on the mean probability of illness, examples of foods from the food categories ranked from most to least risk of illness were: (1) home-made salad dressings/ice cream; (2) fried eggs/boiled eggs; (3) omelettes; and (4) baked foods/breads. For food categories that may include uncooked eggs (e.g., home-made salad dressings/ice cream), consumer handling conditions such as storage time and temperature after food preparation were the key sources of variability. In contrast, for food categories associated with undercooked eggs (e.g., fried/soft-boiled eggs), the initial level of Salmonella contamination and the log10 reduction due to cooking were the key sources of variability. Important sources of uncertainty varied with both the risk percentile and the food category under consideration. This work adds to previous risk assessments focused on egg production and storage practices, and provides a science-based approach to inform consumer risk communications regarding safe egg handling practices.}, number={3}, journal={RISK ANALYSIS}, author={Mokhtari, Amirhossein and Moore, Christina M. and Yang, Hong and Jaykus, Lee-Ann and Morales, Roberta and Cates, Sheryl C. and Cowen, Peter}, year={2006}, month={Jun}, pages={753–768} }
 @article{dh d'souza_sair_williams_papafragkou_jean_moore_jaykus_2006, title={Persistence of caliciviruses on enviromnental surfaces and their transfer to food}, volume={108}, ISSN={["1879-3460"]}, DOI={10.1016/j.ijfoodmicro.2005.10.024}, abstractNote={The noroviruses (NoV) are a common cause of human gastroenteritis whose transmission by foodborne routes is well documented. Fecally contaminated surfaces are likely to contribute to this foodborne transmission and to the propagation of viral disease outbreaks. The purpose of this study was to (i) investigate the stability of NoV on various food preparation surfaces; and (ii) evaluate the degree of virus transfer from these surfaces to a model-ready-to-eat (RTE) food. For the virus persistence experiments, stainless steel, formica and ceramic coupons were artificially contaminated with Norwalk virus (NV), the prototype genogroup I NoV; NV RNA; or feline calicivirus (FCV) F9 (a NoV surrogate), stored at ambient temperature for up to 7 d, and periodically assayed for detection. In the transfer experiments, stainless steel coupons were inoculated with NV or FCV F9 and allowed to dry for 10, 30 and 60 min, after which lettuce leaves were exposed to the surface of the coupons at various contact pressures (10, 100, and 1000 g/9 cm2). Virus recovery was evaluated by RT-PCR (for NV and NV RNA) or by plaque assay (for FCV F9) using Crandell Reese Feline Kidney (CRFK) cells. NV and FCV were detected on all three surfaces for up to 7 d post-inoculation; for FCV, there was an approximate 6 to 7-log10 drop in virus titer over the 7 d evaluation period. By contrast, when stainless steel was inoculated with purified NV RNA, RT-PCR detection was not possible beyond 24 h. Transfer of both NV and FCV from stainless steel surfaces to lettuce occurred with relative ease. This study confirms lengthy NoV persistence on common food preparation surfaces and their ease of transfer, confirming a potential role for environmental contamination in the propagation of viral gastroenteritis.}, number={1}, journal={INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY}, author={DH D'Souza and Sair, A and Williams, K and Papafragkou, E and Jean, J and Moore, C and Jaykus, L}, year={2006}, month={Apr}, pages={84–91} }
 @article{cannon_papafragkou_park_osborne_jaykus_vinje_2006, title={Surrogates for the study of norovirus stability and inactivation in the environment: A comparison of murine norovirus and feline calicivirus}, volume={69}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-69.11.2761}, abstractNote={Human noroviruses (NoVs) are the leading cause of food- and waterborne outbreaks of acute nonbacterial gastroenteritis worldwide. As a result of the lack of a mammalian cell culture model for these viruses, studies on persistence, inactivation, and transmission have been limited to cultivable viruses, including feline calicivirus (FCV). Recently, reports of the successful cell culture of murine norovirus 1 (MNV-1) have provided investigators with an alternative surrogate for human NoVs. In this study, we compared the inactivation profiles of MNV-1 to FCV in an effort to establish the relevance of MNV-1 as a surrogate virus. Specifically, we evaluated (i) stability upon exposure to pH extremes; (ii) stability upon exposure to organic solvents; (iii) thermal inactivation; and (iv) surface persistence under wet and dry conditions. MNV-1 was stable across the entire pH range tested (pH 2 to 10) with less than 1 log reduction in infectivity at pH 2, whereas FCV was inactivated rapidly at pH values < 3 and > 9. FCV was more stable than MNV-1 at 56 degrees C, but both viruses exhibited similar inactivation at 63 and 72 degrees C. Long-term persistence of both viruses suspended in a fecal matrix and inoculated onto stainless steel coupons were similar at 4 degrees C, but at room temperature in solution, MNV-1 was more stable than FCV. The genetic relatedness of MNV-1 to human NoVs combined with its ability to survive under gastric pH levels makes this virus a promising and relevant surrogate for studying environmental survival of human NoVs.}, number={11}, journal={JOURNAL OF FOOD PROTECTION}, author={Cannon, Jennifer L. and Papafragkou, Efstathia and Park, Geunwoo W. and Osborne, Jason and Jaykus, Lee-Ann and Vinje, Jan}, year={2006}, month={Nov}, pages={2761–2765} }
 @article{isonhood_drake_jaykus_2006, title={Upstream sample processing facilitates PCR detection of Listeria monocytogenes in mayonnaise-based ready-to-eat (RTE) salads}, volume={23}, ISSN={["1095-9998"]}, DOI={10.1016/j.fm.2005.09.004}, abstractNote={Sample pretreatment to reduce volume and concentrate cells of the target organism(s) prior to molecular detection offers a useful supplement or alternative to cultural enrichment. The purpose of this study was to develop an upstream processing method to facilitate the detection of Listeria monocytogenes in ready-to-eat (RTE) salads by PCR. Potato salad, a model RTE commodity, was seeded with L. monocytogenes and processed by two alternative upstream sample processing methods (designated one-step and two-step centrifugation), followed by DNA extraction, PCR amplification, and Southern hybridization. The two-step method resulted in 1000-fold improvements in the PCR detection limit, from 106 Cfu/g (no sample processing) to 103 Cfu/g. The two-step method was applied for upstream sample processing of four representative deli salad items artificially inoculated with L. monocytogenes at levels ranging from 101–106 Cfu/g. Following DNA extraction, PCR amplification, and Southern hybridization, detection was achieved at input levels of 105 Cfu/g for chicken salad, 104 Cfu/g for macaroni salad, and 103 Cfu/g for potato and seafood salads. The two-step method reported here facilitates the production of a final sample concentrate of reduced volume and improved purity which was compatible with PCR amplification. This approach offers further progress in our efforts to reduce or eliminate cultural enrichment in an effort to speed time to results when applying molecular methods to the detection of pathogens in foods.}, number={6}, journal={FOOD MICROBIOLOGY}, author={Isonhood, Jamie and Drake, MaryAnne and Jaykus, Lee-Ann}, year={2006}, month={Sep}, pages={584–590} }
 @article{drake_elhanafi_bang_drake_green_jaykus_2006, title={Validation of a green fluorescent protein-labeled strain of Vibrio vulnificus for use in the evaluation of postharvest strategies for handling of raw oysters}, volume={72}, ISSN={["0099-2240"]}, DOI={10.1128/AEM.01091-06}, abstractNote={ABSTRACT In this paper we describe a biological indicator which can be used to study the behavior of Vibrio vulnificus , an important molluscan shellfish-associated human pathogen. A V. vulnificus ATCC 27562 derivative that expresses green fluorescent protein (GFP) and kanamycin resistance was constructed using conjugation. Strain validation was performed by comparing the GFP-expressing strain ( Vv- GFP) and the wild-type strain ( Vv -WT) with respect to growth characteristics, heat tolerance (45°C), freeze-thaw tolerance (−20 o and −80°C), acid tolerance (pH 5.0, 4.0, and 3.5), cold storage tolerance (5°C), cold adaptation (15°C), and response to starvation. Levels of recovery were evaluated using nonselective medium (tryptic soy agar containing 2% NaCl) with and without sodium pyruvate. The indicator strain was subsequently used to evaluate the survival of V. vulnificus in oysters exposed to organic acids (citric and acetic acids) and various cooling regimens. In most cases, Vv -GFP was comparable to Vv -WT with respect to growth and survival upon exposure to various biological stressors; when differences between the GFP-expressing and parent strains occurred, they usually disappeared when sodium pyruvate was added to media. When V. vulnificus was inoculated into shellstock oysters, the counts dropped 2 log 10 after 11 to 12 days of refrigerated storage, regardless of the way in which the oysters were initially cooled. Steeper population declines after 12 days of refrigerated storage were observed for both iced and refrigerated products than for slowly cooled product and product held under conservative harvest conditions. By the end of the refrigeration storage study (22 days), the counts of Vv -GFP in iced and refrigerated oysters had reached the limit of detection (10 2 CFU/oyster), but slowly cooled oysters and oysters stored under conservative harvest conditions still contained approximately 10 3 and >10 4 CFU V. vulnificus /oyster by day 22, respectively. The Vv -GFP levels in the oyster meat remained stable for up to 24 h when the meat was exposed to acidic conditions at various pH values. Ease of detection and comparability to the wild-type parent make Vv -GFP a good candidate for use in studying the behavior of V. vulnificus upon exposure to sublethal stressors that might be encountered during postharvest handling of molluscan shellfish.}, number={11}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Drake, S. L. and Elhanafi, D. and Bang, W. and Drake, M. A. and Green, D. P. and Jaykus, L. A.}, year={2006}, month={Nov}, pages={7205–7211} }
 @article{johnston_jaykus_moll_martinez_anciso_mora_moe_2005, title={A field study of the microbiological quality of fresh produce}, volume={68}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-68.9.1840}, abstractNote={The Centers for Disease Control and Prevention has reported that foodborne disease outbreaks associated with fruits and vegetables increased during the past decade. This study was conducted to characterize the routes of microbial contamination in produce and to identify areas of potential contamination from production through postharvest handling. We report here the levels of bacterial indicator organisms and the prevalence of selected pathogens in produce samples collected from the southern United States. A total of 398 produce samples (leafy greens, herbs, and cantaloupe) were collected through production and the packing shed and assayed by enumerative tests for total aerobic bacteria, total coliforms, total Enterococcus, and Escherichia coli. These samples also were analyzed for Salmonella, Listeria monocytogenes, and E. coli O157:H7. Microbiological methods were based on methods recommended by the U.S. Food and Drug Administration. For all leafy greens and herbs, geometric mean indicator levels ranged from 4.5 to 6.2 log CFU/g (aerobic plate count); less than 1 to 4.3 log CFU/g (coliforms and Enterococcus); and less than 1 to 1.5 log CFU/g (E. coli). In many cases, indicator levels remained relatively constant throughout the packing shed, particularly for mustard greens. However, for cilantro and parsley, total coliform levels increased during the packing process. For cantaloupe, microbial levels significantly increased from field through packing, with ranges of 6.4 to 7.0 log CFU/g (aerobic plate count); 2.1 to 4.3 log CFU/g (coliforms); 3.5 to 5.2 log CFU/g (Enterococcus); and less than 1 to 2.5 log CFU/g (E. coli). The prevalence of pathogens for all samples was 0, 0, and 0.7% (3 of 398) for L. monocytogenes, E. coli O157:H7, and Salmonella, respectively. This study demonstrates that each step from production to consumption may affect the microbial load of produce and reinforces government recommendations for ensuring a high-quality product.}, number={9}, journal={JOURNAL OF FOOD PROTECTION}, author={Johnston, LM and Jaykus, LA and Moll, D and Martinez, MC and Anciso, J and Mora, B and Moe, CL}, year={2005}, month={Sep}, pages={1840–1847} }
 @article{johnston_elhanafi_drake_jaykus_2005, title={A simple method for the direct detection of Salmonella and Escherichia coli O157 : H7 from raw alfalfa sprouts and spent irrigation water using PCR}, volume={68}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-68.11.2256}, abstractNote={The U.S. Food and Drug Administration recognizes that raw seed sprouts are an important cause of foodborne disease and is now recommending that either spent irrigation water or final product be screened for Salmonella and Escherichia coli O157:H7 as a means of assuring the safety of product intended for consumption. In an effort to streamline such testing efforts, a simple method to preconcentrate pathogens from sprouts and spent irrigation water was investigated to facilitate the direct (without prior cultural enrichment) detection of pathogens using the PCR technique. Alfalfa sprouts and spent irrigation water were seeded with Salmonella enterica serovar Typhimurium and E. coli O157:H7 at 10(-1) to 106 CFU/g or CFU/ml, respectively. Samples were blended (sprouts only) and then centrifuged at high speed to sediment the total bacterial population. The precipitate was processed for DNA isolation, PCR amplification, and amplicon confirmation by Southern hybridization. Mean pathogen recoveries after centrifugation ranged from 96 to 99% for both pathogens in both matrices. Using primers targeting the invA gene for Salmonella Typhimurium and the stx genes of E. coli O157:H7, it was possible to detect both pathogens in alfalfa sprouts at seeding concentrations as low as 10 CFU/g. PCR detection limits for both pathogens from spent irrigation water were 10(-1) CFU/ml, the equivalent of 100 CFU/liter of water. Because spent irrigation water is constitutionally simple, it is particularly well suited for bacterial concentration by simple centrifugation steps. In this study, progress was made toward development of a rapid, inexpensive, and sensitive method for the detection of sprout-associated pathogens that is relevant to current industrial practices and needs.}, number={11}, journal={JOURNAL OF FOOD PROTECTION}, author={Johnston, LM and Elhanafi, D and Drake, M and Jaykus, LA}, year={2005}, month={Nov}, pages={2256–2263} }
 @article{allen_green_bolton_jaykus_cope_2005, title={Detection and identification of histamine-producing bacteria associated with harvesting and processing mahimahi and yellowfin tuna}, volume={68}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-68.8.1676}, abstractNote={Histamine poisoning is one of the most common chemically induced seafoodborne illnesses reported in the United States today. The causative agents are biogenic amines, commonly produced by gram-negative bacteria. The purpose of this study was to detect and identify histamine-producing bacteria associated with standard industry practices during the harvesting, receiving, and processing of mahimahi and yellowfin tuna in North Carolina. Twenty-nine composite samples were obtained from 18 mahimahi and 11 yellowfin tuna and analyzed for their histamine content. No sample analyzed exceeded 2 ppm histamine, the lower detection limit. Composite fish muscle and environmental samples were screened (n = 386) for the presence of histamine-producing bacteria. Twenty-six percent (145) of 549 isolates selected on the basis of their morphological characteristics tested positive on Niven's media. Sixty-three Niven-positive isolates were gram negative, and 58 were gram positive. Of the 43 isolates tested further, 5 were confirmed as histamine producers, and all 5 produced at low levels (< 250 ppm in 48 h at > 15 degrees C). Three gram-negative and two gram-positive isolates were identified as Enterobacter cloacae and Staphylococcus kloosii, respectively. This study revealed that gram-negative bacteria might not be solely responsible for histamine production in at-risk fish. The confirmation of histamine-producing bacteria demonstrates the potential risk for histamine production. However, no detectable levels were found in the composite fish muscle samples analyzed even though 60% of the yellowfin tuna harvested did not meet the U.S. Food and Drug Administration's regulatory hazard analysis critical control point guidelines for temperature reduction. Therefore, no seafood safety risks were found under the standard industry practices observed in this study.}, number={8}, journal={JOURNAL OF FOOD PROTECTION}, author={Allen, DG and Green, DP and Bolton, GE and Jaykus, LA and Cope, WG}, year={2005}, month={Aug}, pages={1676–1682} }
 @article{taylor_elhanafi_drake_jaykus_2005, title={Effect of food matrix and cell growth on PCR-based detection of Escherichia coli O157 : H7 in ground beef}, volume={68}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-68.2.225}, abstractNote={The purpose of this work was (i) to investigate the feasibility of a previously reported upstream processing method for PCR template preparation to facilitate the detection of Escherichia coli O157:H7 from ground beef and (ii) to assess the impact of cell growth (no growth in the matrix versus growth in the matrix) on molecular detection limits. Two food matrices (autoclaved and raw ground beef) were evaluated in all studies. For no-growth experiments, 10-g meat samples were inoculated with 10(2) to 10(7) CFU/g E. coli O157:H7 and then homogenized. The homogenates were processed to remove large particulates and inhibitors using a two-phase upstream processing method consisting of two sequential centrifugation steps, the second of which used titanous hydroxide to facilitate bacterial immobilization. After upstream processing, sample concentrates were extracted for DNA isolation and amplified by PCR. For growth experiments, 10-g meat samples were inoculated at 1 CFU of E. coli O157:H7 per gram, allowed to grow to 10(2) to 10(7) CFU/g, and then processed for PCR assay. Cell recoveries after upstream processing ranged from 15.9 to 77.6% and were not facilitated by the use of titanous hydroxide, as compared with a saline control (P > 0.05). Bacterial cell recovery and PCR detection limits were similar when comparing autoclaved ground beef and raw ground beef, but cell recoveries were highly variable for raw ground beef samples in which E. coli O157:H7 cells were allowed to grow before processing for detection. Overall, PCR detection limits approximated 10(3) CFU/g of ground beef for all treatments. These results indicate that use of model food systems may not always provide an accurate replication of real-world conditions when evaluating PCR detection limits.}, number={2}, journal={JOURNAL OF FOOD PROTECTION}, author={Taylor, TM and Elhanafi, D and Drake, M and Jaykus, LA}, year={2005}, month={Feb}, pages={225–232} }
 @article{eifert_curtis_bazaco_meinersmann_berrang_kernodle_stam_jaykus_kathariou_2005, title={Molecular characterization of Listeria monocytogenes of the serotype 4b complex (4b, 4d, 4e) from two turkey processing plants}, volume={2}, ISSN={["1556-7125"]}, DOI={10.1089/fpd.2005.2.192}, abstractNote={Most foodborne outbreaks of listeriosis have been found to involve a small number of closely related strains of Listeria monocytogenes serotype 4b. The ecology of these organisms and their reservoirs in nature or in the processing plant environment, however, remain poorly understood. Surveys of environmental samples from two turkey processing plants in the United States indicated presence of L. monocytogenes of the serotype 4b complex (serotype 4b and the closely related serotypes 4d and 4e). In addition, environmental and raw product samples from one plant repeatedly yielded isolates with genetic markers typical of two major serotype 4b epidemic clonal groups, ECI and ECII. The pulsed field gel electrophoresis (PFGE) profiles of these isolates, however, were clearly distinct from those of confirmed epidemic-associated strains. Furthermore, we observed minor but consistent differences in PFGE profiles of isolates that harbored ECI- or ECII-specific genetic markers, and that were obtained at different sampling times from the same plant. The findings suggest processing plant persistence (or repeated introductions) and genomic diversification of L. monocytogenes serotype 4b isolates that harbor ECI- or ECII-specific genetic markers. Such diversification would need to be taken into consideration in further efforts to elucidate the evolution and epidemiology of these organisms.}, number={3}, journal={FOODBORNE PATHOGENS AND DISEASE}, author={Eifert, J. D. and Curtis, P. A. and Bazaco, M. C. and Meinersmann, R. J. and Berrang, M. E. and Kernodle, S. and Stam, C. and Jaykus, L. -A. and Kathariou, S.}, year={2005}, pages={192–200} }
 @article{johnston_jaykus_2004, title={Antimicrobial resistance of Enterococcus species isolated from produce}, volume={70}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.70.5.3133-3137.2004}, abstractNote={ABSTRACT The purpose of this study was to characterize the antibiotic resistance profiles of Enterococcus species isolated from fresh produce harvested in the southwestern United States. Among the 185 Enterococcus isolates obtained, 97 (52%) were Enterococcus faecium , 38 (21%) were Enterococcus faecalis , and 50 (27%) were other Enterococcus species. Of human clinical importance, E. faecium strains had a much higher prevalence of resistance to ciprofloxacin, tetracycline, and nitrofurantoin than E. faecalis. E. faecalis strains had a low prevalence of resistance to antibiotics used to treat E. faecalis infections of both clinical and of agricultural relevance, excluding its intrinsic resistance patterns. Thirty-four percent of the isolates had multiple-drug-resistance patterns, excluding intrinsic resistance. Data on the prevalence and types of antibiotic resistance in Enterococcus species isolated from fresh produce may be used to describe baseline antibiotic susceptibility profiles associated with Enterococcus spp. isolated from the environment. The data collected may also help elucidate the role of foods in the transmission of antibiotic-resistant strains to human populations.}, number={5}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Johnston, LM and Jaykus, LA}, year={2004}, month={May}, pages={3133–3137} }
 @misc{stevens_jaykus_2004, title={Bacterial separation and concentration from complex sample matrices: A review}, volume={30}, ISSN={["1549-7828"]}, DOI={10.1080/10408410490266410}, abstractNote={The use of many rapid detection technologies could be expanded if the bacteria were separated, concentrated, and purified from the sample matrix before detection. Specific advantages of bacterial concentration might include facilitating the detection of multiple bacterial strains; removal of matrix-associated assay inhibitors; and provision of adequate sample size reduction to allow for the use of representative food sample sizes and/or small media volumes. Furthermore, bacterial concentration could aid in improving sampling techniques needed to detect low levels of pathogens or sporadic contamination, which may perhaps reduce or even eliminate the need for cultural enrichment prior to detection. Although bacterial concentration methods such as centrifugation, filtration, and immunomagnetic separation have been reported for food systems, none of these is ideal and in many cases a technique optimized for one food system or microorganism is not readily adaptable to others. Indeed, the separation and subsequent concentration of bacterial cells from a food sample during sample preparation continues to be a stumbling block in the advancement of molecular methods for the detection of foodborne pathogens. The purpose of this review is to provide a detailed understanding of the science, possibilities, and limitations of separating and concentrating bacterial cells from the food matrix in an effort to further improve our ability to harness molecular methods for the rapid detection of foodborne pathogens.}, number={1}, journal={CRITICAL REVIEWS IN MICROBIOLOGY}, author={Stevens, KA and Jaykus, LA}, year={2004}, pages={7–24} }
 @article{moe_sair_lindesmith_estes_jaykus_2004, title={Diagnosis of Norwalk virus infection by indirect enzyme immunoassay detection of salivary antibodies to recombinant Norwalk virus antigen}, volume={11}, ISSN={["1071-412X"]}, DOI={10.1128/CDLI.11.6.1028-1034.2004}, abstractNote={ABSTRACT Simple diagnostic tests are needed for the detection of norovirus (NoV) outbreaks. Salivary antibody assays provide an attractive alternative to collecting and testing serum or stool samples. Antibodies to Norwalk virus (NV) in oral fluid samples were compared with NV antibodies in serum collected from 38 volunteers challenged with NV inoculum. Pre- and postchallenge (day 4, 8, 14, and 21) saliva and serum samples were examined by enzyme immunoassay (EIA) using recombinant NV antigen. Of 18 infected subjects (those who shed NV in stool or who demonstrated immunoglobulin G [IgG] seroconversion), 15 (83%) had ≥4-fold increases in NV-specific salivary IgA and 15 (83%) had ≥4-fold increases in NV-specific salivary IgG when prechallenge and postchallenge saliva samples were compared. When the results of the IgA and IgG assays were combined, all 18 infected subjects showed ≥4-fold increases in NV-specific salivary IgG or IgA postchallenge titers compared to their prechallenge titers. One of 19 uninfected subjects had a ≥4-fold increase in NV-specific salivary IgG. The sensitivity of the combined assay results was 100%, and the specificity was 95%. NV-specific salivary IgA titers peaked around 14 days postchallenge. NV-specific salivary IgG and serum IgG titers continued to rise through 21 days postchallenge. The application of this EIA to an elementary school outbreak indicated that 67% of the subjects with confirmed infections had >4-fold rises in anti-NoV IgA when an antigen in the same genetic cluster as the outbreak virus was used. This is the first documented mucosal antibody response to NoV in children. This EIA provides a useful approach for diagnosing NoV outbreaks.}, number={6}, journal={CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY}, author={Moe, CL and Sair, A and Lindesmith, L and Estes, MK and Jaykus, LA}, year={2004}, month={Nov}, pages={1028–1034} }
 @article{stevens_jaykus_2004, title={Direct detection of bacterial pathogens in representative dairy products using a combined bacterial concentration-PCR approach}, volume={97}, ISSN={["1365-2672"]}, DOI={10.1111/j.1365-2672.2004.02393.x}, abstractNote={To develop a simple, rapid method to concentrate and purify bacteria and their nucleic acids from complex dairy food matrices in preparation for direct pathogen detection using polymerase chain reaction (PCR).Plain non-fat yogurt and cheddar cheese were each seeded with Listeria monocytogenes or Salmonella enterica serovar. Enteritidis in the range of 10(1)-10(6) CFU per 11-g sample. Samples were then processed for bacterial concentration using high-speed centrifugation (9700 g) followed by DNA extraction, PCR amplification, and amplicon confirmation by hybridization. Bacterial recoveries after centrifugation ranged from 53 to >100% and 71 to >100% for serovar. Enteritidis and L. monocytogenes, respectively, in the non-fat yogurt samples; and from 77 to >100% and 69 to >100% for serovar. Enteritidis and L. monocytogenes, respectively, in the cheddar cheese samples. There were no significant differences in recovery efficiency at different inocula levels, and losses to discarded supernatants were always <5%, regardless of dairy product or pathogen.When followed by pathogen detection using PCR and confirmation by amplicon hybridization, detection limits of 10(3) and 10(1) CFU per 11-g sample were achieved for L. monocytogenes and serovar. Enteritidis, respectively, in both product types and without prior cultural enrichment.This study represents progress toward the rapid and efficient direct detection of pathogens from complex food matrices at detection limits approaching those that might be anticipated in naturally contaminated products.}, number={6}, journal={JOURNAL OF APPLIED MICROBIOLOGY}, author={Stevens, KA and Jaykus, LA}, year={2004}, pages={1115–1122} }
 @article{yildirim_lin_hitchins_jaykus_altermann_klaenhammer_kathariou_2004, title={Epidemic clone I-specific genetic markers in strains of Listeria monocytogenes serotype 4b from foods}, volume={70}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.70.7.4158-4164.2004}, abstractNote={ABSTRACT Listeria monocytogenes contamination of ready-to-eat foods has been implicated in numerous outbreaks of food-borne listeriosis. However, the health hazards posed by L. monocytogenes detected in foods may vary, and speculations exist that strains actually implicated in illness may constitute only a fraction of those that contaminate foods. In this study, examination of 34 serogroup 4 (putative or confirmed serotype 4b) isolates of L. monocytogenes obtained from various foods and food-processing environments, without known implication in illness, revealed that many of these strains had methylation of cytosines at GATC sites in the genome, rendering their DNA resistant to digestion by the restriction endonuclease Sau3AI. These strains also harbored a gene cassette with putative restriction-modification system genes as well as other, genomically unlinked genetic markers characteristic of the major epidemic-associated lineage of L. monocytogenes (epidemic clone I), implicated in numerous outbreaks in Europe and North America. This may reflect a relatively high fitness of strains with these genetic markers in foods and food-related environments relative to other serotype 4b strains and may partially account for the repeated involvement of such strains in human food-borne listeriosis.}, number={7}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Yildirim, S and Lin, W and Hitchins, AD and Jaykus, LA and Altermann, E and Klaenhammer, TR and Kathariou, S}, year={2004}, month={Jul}, pages={4158–4164} }
 @article{yildirim_lin_hitchins_jaykus_altermann_klaenhammer_kathariou_2004, title={Epidemic clone I-specific genetic markers in strains of Listeria monocytogenes serotype 4b from foods (vol 70, pg 4158, 2004)}, volume={70}, ISSN={["0099-2240"]}, DOI={10.1128/aem.70.12.7581.2004}, abstractNote={Listeria monocytogenes contamination of ready-to-eat foods has been implicated in numerous outbreaks of food-borne listeriosis. However, the health hazards posed by L. monocytogenes detected in foods may vary, and speculations exist that strains actually implicated in illness may constitute only a fraction of those that contaminate foods. In this study, examination of 34 serogroup 4 (putative or confirmed serotype 4b) isolates of L. monocytogenes obtained from various foods and food-processing environments, without known implication in illness, revealed that many of these strains had methylation of cytosines at GATC sites in the genome, rendering their DNA resistant to digestion by the restriction endonuclease Sau3AI. These strains also harbored a gene cassette with putative restriction-modification system genes as well as other, genomically unlinked genetic markers characteristic of the major epidemic-associated lineage of L. monocytogenes (epidemic clone I), implicated in numerous outbreaks in Europe and North America. This may reflect a relatively high fitness of strains with these genetic markers in foods and food-related environments relative to other serotype 4b strains and may partially account for the repeated involvement of such strains in human food-borne listeriosis. Food contamination by Listeria monocytogenes has been implicated in numerous outbreaks and sporadic cases of human illness. Most commonly implicated in listeriosis are highly processed, ready-to-eat (RTE) foods that are kept refrigerated for various periods of time. At risk for listeriosis are people in the extremes of age, pregnant women and their fetuses, cancer patients, and others experiencing immunosuppression (13, 24, 35, 38). Listeriosis can have severe symptoms (septicemia, meningitis, and stillbirths) and a high mortality rate (20 to 30%). Hence, regulations exist in numerous nations concerning the density (e.g., 1 CFU/25 g) of cells of the etiologic agent permissible in RTE foods. Such regulations are based on the hypothesis that any L. monocytogenes strain that can be detected in RTE foods has the potential to pose serious hazards to human health. The potential hazard posed by listerial contamination of RTE foods can be influenced by the number of cells at the point of consumption, which would depend on conditions of storage, type of food matrix and its impact on growth, presence of competing microflora and antimicrobial agents, etc. In addition, the strain type of L. monocytogenes involved may be of importance. It is likely, based on studies with other bacterial pathogens, that some strains and strain clusters (clonal groups) within the species might be more pathogenic than others. Speculations have been formulated that only a fraction of the strains of L. monocytogenes found in foods may be capable of causing human illness (20). There is indeed evidence that the repertoire of strains ca}, number={12}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Yildirim, S and Lin, W and Hitchins, AD and Jaykus, LA and Altermann, E and Klaenhammer, TR and Kathariou, S}, year={2004}, month={Dec}, pages={7581–7581} }
 @article{jaykus_acuff_busta_dickson_hollingsworth_marcy_mcnamara_2004, title={Managing food safety: A systematic approach}, volume={58}, number={10}, journal={Food Technology}, author={Jaykus, L. A. and Acuff, G. R. and Busta, F. F. and Dickson, J. S. and Hollingsworth, C. A. and Marcy, J. and McNamara, A. M.}, year={2004}, pages={36–39} }
 @article{jean_dh d'souza_jaykus_2004, title={Multiplex nucleic acid sequence-based amplification for simultaneous detection of several enteric viruses in model ready-to-eat foods}, volume={70}, ISSN={["0099-2240"]}, DOI={10.1128/AEM.70.11.6603-6610.2004}, abstractNote={ABSTRACT Human enteric viruses are currently recognized as one of the most important causes of food-borne disease. Implication of enteric viruses in food-borne outbreaks can be difficult to confirm due to the inadequacy of the detection methods available. In this study, a nucleic acid sequence-based amplification (NASBA) method was developed in a multiplex format for the specific, simultaneous, and rapid detection of epidemiologically relevant human enteric viruses. Three previously reported primer sets were used in a single reaction for the amplification of RNA target fragments of 474, 371, and 165 nucleotides for the detection of hepatitis A virus and genogroup I and genogroup II noroviruses, respectively. Amplicons were detected by agarose gel electrophoresis and confirmed by electrochemiluminescence and Northern hybridization. Endpoint detection sensitivity for the multiplex NASBA assay was approximately 10 −1 reverse transcription-PCR-detectable units (or PFU, as appropriate) per reaction. When representative ready-to-eat foods (deli sliced turkey and lettuce) were inoculated with various concentrations of each virus and processed for virus detection with the multiplex NASBA method, all three human enteric viruses were simultaneously detected at initial inoculum levels of 10 0 to 10 2 reverse transcription-PCR-detectable units (or PFU)/9 cm 2 in both food commodities. The multiplex NASBA system provides rapid and simultaneous detection of clinically relevant food-borne viruses in a single reaction tube and may be a promising alternative to reverse transcription-PCR for the detection of viral contamination of foods.}, number={11}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Jean, J and DH D'Souza and Jaykus, LA}, year={2004}, month={Nov}, pages={6603–6610} }
 @article{jaykus_2003, title={Challenges to developing real-time methods to detect pathogens in foods}, volume={69}, number={7}, journal={ASM News}, author={Jaykus, L. A.}, year={2003}, pages={341–347} }
 @article{koo_jaykus_2003, title={Detection of Listeria monocytogenes from a model food by fluorescence resonance energy transfer-based PCR with an asymmetric fluorogenic probe set}, volume={69}, ISSN={["0099-2240"]}, DOI={10.1128/AEM.69.2.1082-1088.2003}, abstractNote={ABSTRACT It has been shown that fluorescence resonance energy transfer (FRET)-based PCR, including the TaqMan assay and molecular beacons, has potential for rapid detection of pathogens. In these promising real-time detection assays a single internal oligonucleotide probe labeled on both the 5′ (reporter) and 3′ (quencher) ends is used for selective generation of fluorescence. In this paper, we describe the use of a previously reported novel probe design for FRET-based PCR detection of Listeria monocytogenes in pure culture and in a model food commodity. In the assay described here an asymmetric probe set is used; this probe set consists of a long 5′ fluorescein-labeled reporter probe and a short, complementary 3′ DABCYL-labeled quencher oligonucleotide, which are used in a 5′ nuclease amplification and detection assay. By using the listeriolysin O ( hly ) and p60 ( iap ) genes as amplification targets, the performance of two primer-probe sets in amplification and subsequent detection of target DNA was evaluated. In studies performed with pure cultures of L. monocytogenes , the PCR profiles indicated that the relative change in fluorescence intensity was correlated with both the initial number of cells and the accumulation of specific amplicons for both hly and iap gene fragments. Experiments were also done to determine the applicability of the method to the detection of L. monocytogenes by targeting hly DNA and its short-lived mRNA product in a model food commodity. Twenty-five-milliliter samples of reconstituted nonfat dry milk (NFDM) were seeded with L. monocytogenes and processed to concentrate the bacteria by centrifugation, and this was followed by nucleic acid extraction and amplification with hly -specific primers. Endpoint detection of PCR and reverse transcription-PCR amplicons could be achieved at inoculum levels of 10 3 and 10 4 CFU of L. monocytogenes /25 ml of NFDM, respectively. This study demonstrated that this asymmetric FRET-based amplification and detection protocol provides an alternative approach for endpoint detection of nucleic acid amplification products as applied to detection of pathogens in a model food.}, number={2}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Koo, K and Jaykus, LA}, year={2003}, month={Feb}, pages={1082–1088} }
 @article{dh d'souza_jaykus_2003, title={Nucleic acid sequence based amplification for the rapid and sensitive detection of Salmonella enterica from foods}, volume={95}, ISSN={["1364-5072"]}, DOI={10.1046/j.1365-2672.2003.02106.x}, abstractNote={Journal Article Nucleic acid sequence based amplification for the rapid and sensitive detection of Salmonella enterica from foods Get access D.H. D'Souza, D.H. D'Souza Department of Food Science, North Carolina State University, Raleigh, NC, USA Doris H. D'Souza, Department of Food Science, 318 Schaub Hall, North Carolina State University, Raleigh, NC 27695‐7624, USA (e‐mail: ddsouza@unity.ncsu.edu). Search for other works by this author on: Oxford Academic Google Scholar L.‐A. Jaykus L.‐A. Jaykus Department of Food Science, North Carolina State University, Raleigh, NC, USA Search for other works by this author on: Oxford Academic Google Scholar Journal of Applied Microbiology, Volume 95, Issue 6, 1 December 2003, Pages 1343–1350, https://doi.org/10.1046/j.1365-2672.2003.02106.x Published: 01 December 2003 Article history Received: 09 June 2003 Revision received: 19 August 2003 Accepted: 19 August 2003 Published: 01 December 2003}, number={6}, journal={JOURNAL OF APPLIED MICROBIOLOGY}, author={DH D'Souza and Jaykus, LA}, year={2003}, pages={1343–1350} }
 @article{de cesare_sheldon_smith_jaykus_2003, title={Survival and persistence of Campylobacter and Salmonella species under various organic loads on food contact surfaces}, volume={66}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-66.9.1587}, abstractNote={Although many cases of Campylobacter and Salmonella enteritis have been attributed to the undercooking of poultry and other foods, cross-contamination between raw and cooked foods via food contact surfaces and worker contact has also been identified as a significant risk factor. Cross-contamination may be particularly important in relation to the high prevalence of contamination in raw poultry products and other foods and the low infectious doses that have been reported for Campylobacter species. Lag phase and decimal reduction times (D-values at 27 degrees C [81 degrees F] and 60 to 62% relative humidity) were determined for Campylobacter jejuni and Salmonella species (five-strain pools) suspended in either a phosphate-buffered saline (PBS) solution or Trypticase soy broth (TSB) and then inoculated (0.1-ml drop per surface) on 5-cm2 samples of Formica laminate (F), glazed ceramic tile (CT), 304 polished stainless steel (SS), and 100% cotton dishcloth (D). Triplicate samples were collected from each contact surface periodically, and the populations of surviving organisms were enumerated on Campy Cefex and brain heart infusion agars for C. jejuni and Salmonella species, respectively. Lag time and rate of inactivation were influenced by organism type, contact surface, and suspending medium. Initial mean lag times ranging from 60 to 190 min were followed by log-linear (r2 > 0.94) decreases in cell populations that varied across contact surfaces. D-values of 12.5, 19.1, 24.1, and 29.7 min and of 23.7, 10.5, 12.7, and 13.9 min were calculated for C. jejuni suspended in PBS and TSB and then spotted on D, F, SS, and CT surfaces, respectively. The times required to produce a 3-log reduction in population with PBS and TSB ranged from 102 (D) to 247 (F) min and from 112 (CT) to 167 (F) min, respectively. C. jejuni cells suspended in the nutritionally enriched medium (TSB) and spotted on the hard surfaces were inactivated about 1.4 times as fast as cells suspended in PBS. For the Salmonella test strains, D-values of 17.1, 426.6, 118.6, and 41.9 min and of 48.2, 1363.2, 481.8, and 134.2 min were calculated for cells suspended in PBS and TSB and then spotted on D, E SS, and CT surfaces, respectively. In contrast to C. jejuni, Salmonella serotypes were 1.7 to 3.3 times more persistent when suspended in TSB than when suspended in PBS and were 1.2 to 25.3 times more persistent than C. jejuni, depending on the contact surface and the type of suspension fluid (i.e., overall time required to achieve a 3-log reduction in population, lag time + 3 x D). These findings indicate that both the contact surface and the level of organic matter can influence the survival and persistence of C. jejuni and Salmonella species on food contact surfaces.}, number={9}, journal={JOURNAL OF FOOD PROTECTION}, author={De Cesare, A and Sheldon, BW and Smith, KS and Jaykus, LA}, year={2003}, month={Sep}, pages={1587–1594} }
 @article{jean_d d'souza_jaykus_2003, title={Transcriptional enhancement of RT-PCR for rapid and sensitive detection of Noroviruses}, volume={226}, ISSN={["0378-1097"]}, DOI={10.1016/S0378-1097(03)00621-9}, abstractNote={Previously reported nucleic acid sequence-based amplification (NASBA) primers specific for the GII Noroviruses were adapted for reverse transcriptase-polymerase chain reaction (RT-PCR), and detection sensitivity was then enhanced by a subsequent in vitro transcription of the RT-PCR amplicons. The NASBA-derived primers performed comparably to other broadly reactive GII Norovirus primers with respect to detection limits (i.e. 1 RT-PCR amplifiable unit (RT-PCRU) per reaction). Detection limits improved by approximately 1 log(10) to 0.3 RT-PCRU per reaction when transcriptional enhancement and electrochemiluminescence (ECL) hybridization followed RT-PCR. The method shows promise for improved detection sensitivity in instances where very low levels of virus contamination might be anticipated.}, number={2}, journal={FEMS MICROBIOLOGY LETTERS}, author={Jean, J and D D'Souza and Jaykus, LA}, year={2003}, month={Sep}, pages={339–345} }
 @article{moore_sheldon_jaykus_2003, title={Transfer of Salmonella and Campylobacter from stainless steel to romaine lettuce}, volume={66}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-66.12.2231}, abstractNote={The degree of transfer of Campylobacter jejuni and Salmonella enterica serovar Typhimurium was evaluated from a stainless steel contact surface to a ready-to-eat food (lettuce). Stainless steel coupons (25 cm2) were inoculated with a 20-microl drop of either C. jejuni or Salmonella Typhimurium to provide an inoculum level of approximately 10(6) CFU/28 mm2. Wet and dry lettuce (Lactuca sativa var. longifolia) pieces (9 cm2) were placed onto the inoculated stainless steel surface for 10 s after the designated inoculum drying time (0 to 80 min for C. jejuni; 0 to 120 min for Salmonella Typhimurium), which was followed by the recovery and enumeration of transferred pathogens (lettuce) and residual surface pathogens (stainless steel coupons). For transfers of Salmonella Typhimurium to dry lettuce, there was an increase from 36 to 66% in the percent transfer of the initial inoculum load during the first 60 min of sampling and then a precipitous drop from 66 to 6% in percent transfer. The transfer of Salmonella Typhimurium to wet lettuce ranged from 23 to 31%, with no statistically significant difference between recoveries over the entire 120-min sampling period. For C. jejuni, the mean percent transfer ranged from 16 to 38% for dry lettuce and from 15 to 27% for wet lettuce during the 80-min sampling period. The results of this study indicate that relatively high numbers of bacteria may be transferred to a food even 1 to 2 h after surface contamination. These findings can be used to support future projects aimed at estimating the degree of risk associated with poor handling practices of ready-to-eat foods.}, number={12}, journal={JOURNAL OF FOOD PROTECTION}, author={Moore, CM and Sheldon, BW and Jaykus, LA}, year={2003}, month={Dec}, pages={2231–2236} }
 @article{koo_jaykus_2002, title={Detection of single nucleotide polymorphisms within the Listeria genus using an 'asymmetric' fluorogenic probe set and fluorescence resonance energy transfer based-PCR}, volume={35}, ISSN={["0266-8254"]}, DOI={10.1046/j.1472-765X.2002.01232.x}, abstractNote={We describe a novel and inexpensive fluorescence energy transfer (FRET)-based PCR protocol to distinguish single nucleotide polymorphisms (SNPs) within the genus Listeria.Sequence information for the 16S rRNA gene of representative Listeria species was used to design genus-specific primers and two species-specific probes that differed in sequence by one single nucleotide. The probes were 5' labelled with either fluorescein or Texas Red, quenched with a shorter yet complementary 3' dimethyl-amino-phenyloazo benzoic acid (DABCYL) labelled oligonucleotide, and then incorporated into a previously reported 'asymmetric' FRET-based PCR detection protocol.Listeria monocytogenes could be readily distinguished from other members of the Listeria genus after PCR amplification and measurement of endpoint fluorescence at two different wavelengths.The relatively low cost and high flexibility of this system will benefit laboratories in their efforts to develop rapid and specific methods to detect minor sequence differences between related microorganisms.}, number={6}, journal={LETTERS IN APPLIED MICROBIOLOGY}, author={Koo, K and Jaykus, LA}, year={2002}, pages={513–517} }
 @article{sair_dh d'souza_moe_jaykus_2002, title={Improved detection of human enteric viruses in foods by RT-PCR}, volume={100}, ISSN={["1879-0984"]}, DOI={10.1016/S0166-0934(01)00397-4}, abstractNote={Human enteric viruses (including hepatitis A virus (HAV) and Norwalk-like viruses (NLVs)) are now recognized as common causes of foodborne disease. While methods to detect these agents in clinical specimens have improved significantly over the last 10 years, applications to food samples have progressed more slowly. In an effort to improve the sensitivity and speed of virus detection from non-shellfish food commodities by reverse transcription-polymerase chain reaction (RT-PCR), we (i) evaluated multiple RNA extraction methods; (ii) compared alternative NLV primer sets; and (iii) developed a one-step RT-PCR method. Hamburger and lettuce samples, processed for virus concentration using a previously reported filtration-extraction-precipitation procedure, were inoculated with HAV or NV. Several RNA extraction methods (guanidinium isothiocyanate, microspin column, QIAshredder Homogenizer, and TRIzol) and primer pairs were compared for overall RNA yield (microg/ml), purity (A(260)/A(280)), and RT-PCR limits of detection. The use of TRIzol with the QIAshredder Homogenizer (TRIzol/Shred) yielded the best RT-PCR detection limits (<1 RT-PCR amplifiable units/reaction for NV), and the NVp110/NVp36 primer set was the most efficient for detecting NV from seeded food samples. A one-step RT-PCR protocol using the TRIzol/Shred extraction method and the NVp110/NVp36 or HAV3/HAV5 primer sets demonstrated improved sensitivity (>10-fold) over the routinely used two-step method. HAV RNA was detected by RT-PCR at initial inoculum levels corresponding to <10 and <100 PFU per 300 microl sample concentrate (corresponding to 6 g food sample) for hamburger and lettuce, respectively. NV RNA was detected by RT-PCR at initial inoculum levels <5 and <50 RT-PCR amplifiable units per 300 microl concentrate (corresponding to 6 g food sample) for hamburger and lettuce, respectively. Residual RT-PCR inhibitors were effectively removed as evidenced by the ability to detect viral RNA in food concentrates without prior dilution. The methods reported here show promise for rapid, sensitive detection of human enteric viruses in foods.}, number={1-2}, journal={JOURNAL OF VIROLOGICAL METHODS}, author={Sair, AI and DH D'Souza and Moe, CL and Jaykus, LA}, year={2002}, month={Feb}, pages={57–69} }
 @article{mckillip_jaykus_drake_2002, title={Influence of growth in a food medium on the detection of Escherichia coli O157 : H7 by polymerase chain reaction}, volume={65}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-65.11.1775}, abstractNote={The effects of storage time and growth in broth culture and in a food medium on the efficiency of Escherichia coli O157: H7 DNA extraction and on the sensitivity of polymerase chain reaction (PCR) detection of E. coli O157:H7 were investigated. Detection limits were evaluated with dilution series PCR targeting the slt-II gene. The relationship between cell density and DNA yield was generally log-linear for pure cultures of E coli O157:H7. When the bacteria were suspended in skim milk at a density of 10(6) CFU/ml. held at 4 degrees C, and sampled at 24-h intervals, cell density, total DNA yield, and PCR detection limits remained stable throughout the 96-h storage period. However, when E coli O157:H7 was grown in skim milk to a final cell density of 10(6) CFU/ml, PCR amplification efficiency was drastically reduced, although overall DNA yields from these samples were consistent with those for the samples in which E. coli O157:H7 growth was static over 96 h of storage at 4 degrees C. This result is most likely due to poor DNA purity, which was consistently observed when DNA was extracted from food matrices in which the pathogen was grown rather than stored. The results of this investigation underscore the likelihood that multiple components may drastically affect DNA extraction and PCR amplification efficiency in the detection of pathogens in the food matrix. It is clear that before nucleic acid amplification technologies are widely applied to food systems, it would be prudent to test their efficacy in multiple food matrices and under conditions in which the bacterial population is both static and actively growing.}, number={11}, journal={JOURNAL OF FOOD PROTECTION}, author={McKillip, JL and Jaykus, LA and Drake, M}, year={2002}, month={Nov}, pages={1775–1779} }
 @article{cullison_jaykus_2002, title={Magnetized carbonyl iron and insoluble zirconium hydroxide mixture facilitates bacterial concentration and separation from nonfat dry milk}, volume={65}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-65.11.1806}, abstractNote={A mixture of magnetized carbonyl iron and insoluble zirconium hydroxide was investigated for its ability to concentrate various foodborne pathogens from 25-ml samples of reconstituted nonfat dry milk. Each sample was artificially contaminated with 10(3) to 10(6) CFU/25 ml of representative foodborne pathogens (Salmonella enterica serovar Enteritidis, Listeria monocytogenes, and Bacillus cereus spores) and processed for bacterial concentration with high-speed centrifugation for the primary concentration followed by a secondary concentration step involving the carbonyl iron-zirconium hydroxide mixture. Bacterial recoveries, as evaluated on the basis of loss to discarded supernatants, exceeded 75% for all organisms at all inoculum levels and were usually >90%. Recovery was confirmed by direct plating of the immobilized pellet, for which the valueswere similar albeit more varied. Additional experiments confirmed that the magnetized carbonyl iron-insoluble zirconium hydroxide mixture was relatively nontoxic to both Salmonella Enteritidis and L monocytogenes Overall, the entire concentration scheme resulted in a 25-fold reduction in sample volume with the recovery of viable bacterial cells. This novel compound shows promise for facilitating inexpensive, rapid, and effective bacterial concentration in food systems.}, number={11}, journal={JOURNAL OF FOOD PROTECTION}, author={Cullison, MA and Jaykus, LA}, year={2002}, month={Nov}, pages={1806–1810} }
 @article{latimer_jaykus_morales_cowen_crawford-brown_2002, title={Sensitivity analysis of Salmonella enteritidis levels in contaminated shell eggs using a biphasic growth model}, volume={75}, ISSN={["0168-1605"]}, DOI={10.1016/S0168-1605(02)00004-1}, abstractNote={Salmonella enteritidis (SE) is a common foodborne pathogen, the transmission of which is primarily associated with the consumption of contaminated Grade A shell eggs. In order to estimate the level of SE present in raw shell eggs, it is necessary to consider the protective effects of the egg albumin, which effectively inhibits SE growth in a time- and temperature-dependent manner. In this study, a SE growth model was produced by combining two mathematical equations that described both the extended lag phase of SE growth (food component) and a SE growth model (pathogen component). This biphasic growth model was then applied to various egg handling scenarios based on the farm-to-table continuum, including in-line and off-line processing facilities with consideration of key events in production, processing, transportation, and storage. Seasonal effects were also studied. Monte Carlo simulation was used to characterize variability in temperature and time parameter values influencing the level of SE to which individuals are exposed. The total level of SE consumed was estimated under best, most likely, and time–temperature abusive handling scenarios. The model estimated that, in most cases, there was no SE growth in contaminated eggs handled under most likely practices, because 10–70% of the yolk membrane remained intact. Under abusive handling scenarios, complete loss of yolk membrane integrity frequently occurred by the time eggs reach the distribution phase, followed by subsequent SE growth, which was often quite rapid. In general, the effect of season and processing method (in-line vs. off-line) was minimal. Further sensitivity analysis demonstrated that the initial SE contamination level significantly influenced the final exposure levels only under no-abuse or mildly abusive conditions. The results of our study suggest that, for maximum reduction of SE exposure level, cooling strategies should not only focus on the on-farm or processing phases, but should emphasize the importance of cooling strategies at the distribution and consumer phases of the farm-to-fork continuum.}, number={1-2}, journal={INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY}, author={Latimer, HK and Jaykus, LA and Morales, RA and Cowen, P and Crawford-Brown, D}, year={2002}, month={May}, pages={71–87} }
 @article{dh d'souza_jaykus_2002, title={Zirconium hydroxide effectively immobilizes and concentrates human enteric viruses}, volume={35}, ISSN={["1472-765X"]}, DOI={10.1046/j.1472-765X.2002.01206.x}, abstractNote={Detection of human enteric viruses in foods and environmental samples requires concentration of viruses from complex matrices before application of molecular or cultural methods. Previous studies have described the use of zirconium hydroxide to concentrate bacteria from clinical, environmental, and food samples.Our study describes the application of zirconium hydroxide to concentrate human enteric viruses.Poliovirus type 1, hepatitis A virus (HAV) strain HM-175, and Norwalk virus (NV) were used as models. Virus recovery was evaluated both as loss to discarded supernatants and as recovery in the precipitated pellets.Poliovirus type 1, based on the plaque assay recoveries, ranged from 16 to 59% with minimal loss to the supernatant (1-5%). For both HAV and NV, RT-PCR amplicons of appropriate sizes were detected and confirmed in the pellet fraction with no visible amplicons from the supernatant.This rapid and inexpensive method shows promise as an alternative means to concentrate enteric viruses.}, number={5}, journal={LETTERS IN APPLIED MICROBIOLOGY}, author={DH D'Souza and Jaykus, LA}, year={2002}, pages={414–418} }
 @article{latimer_jaykus_morales_cowen_crawford-brown_2001, title={A weighted composite dose-response model for human salmonellosis}, volume={21}, ISSN={["0272-4332"]}, DOI={10.1111/0272-4332.212112}, abstractNote={This article describes the development of a weighted composite dose-response model for human salmonellosis. Data from previously reported human challenge studies were categorized into two different groups representing low and moderately virulent/pathogenic Salmonella strains based on a disease end point. Because epidemiological data indicate that some Salmonella strains are particularly pathogenic, and in the absence of human feeding study data for such strains, Shigella dysenteriae was used as a proxy for highly virulent strains. Three single-hit dose-response models were applied to the human feeding study data and evaluated for best fit using maximum likelihood estimation: (1) the exponential (E-1pop), (2) the two-subpopulation exponential (E-2pop), and (3) the Beta-Poisson (BP). Based on the goodness-of-fit test, the E-1pop and BP were the best-fit models for low and moderately virulent/pathogenic Salmonella strains, and the E-2pop and BP models were better for highly virulent/pathogenic strains. Epistemic analysis was conducted by determining the degree of confidence associated with the selected models, which was found to be 50%/50% (E-1pop/BP) for low and moderately pathogenic Salmonella strains, and 9.8%/90.2% (E-2pop/BP) for highly virulent strains. The degree of confidence for each component model and variations in the proportion of strains within each virulence/pathogenicity category were incorporated into the overall composite model. This study describes the influence of variation in strain virulence and host susceptibility on the shape of the population dose-response relationship.}, number={2}, journal={RISK ANALYSIS}, author={Latimer, HK and Jaykus, LA and Morales, RA and Cowen, P and Crawford-Brown, D}, year={2001}, month={Apr}, pages={295–305} }
 @article{mckillip_jaykus_drake_2000, title={A comparison of methods for the detection of Escherichia coli O157 : H7 from artificially-contaminated dairy products using PCR}, volume={89}, ISSN={["1364-5072"]}, DOI={10.1046/j.1365-2672.2000.01079.x}, abstractNote={Rapid nucleic acid-based methods to detect human pathogens in foods are dependent on the reliability of the DNA or RNA extraction method used. Skim milk, non-fat dry milk, Cheddar and Brie cheese, and reconstituted whey powder were seeded with serially diluted (10(0)-10(7) cfu 10 ml(-1)) Escherichia coli O157:H7 and subjected to DNA extraction (i) directly from the food product using a solvent-based procedure and (ii) using a guanidinium isothiocyanate (GITC) procedure after previous bacterial concentration. Both the efficiency of DNA extraction and the overall PCR detection limits were evaluated. In almost all instances, the total DNA yield using the solvent method was greater than that obtained for the concentration method. However, the purity of the DNA obtained after bacterial concentration was significantly better than that obtained after organic extraction alone. PCR detection limits after each DNA recovery method varied with the specific food, ranging from 10(1) to 10(4) cfu ml(-1) for all products except whey powder. DNA yields and subsequent PCR detection limits for reconstituted whey powder were extremely poor, and neither procedural changes nor the addition of PCR enhancement agents were able to improve recovery and/or detection. It is concluded that the efficiency of DNA extraction is an extremely important and frequently overlooked variable impacting the overall detection limits of PCR-based detection strategies.}, number={1}, journal={JOURNAL OF APPLIED MICROBIOLOGY}, author={McKillip, JL and Jaykus, LA and Drake, MA}, year={2000}, month={Jul}, pages={49–55} }
 @article{leggitt_jaykus_2000, title={Detection methods for human enteric viruses in representative foods}, volume={63}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-63.12.1738}, abstractNote={Although viral foodborne disease is a significant problem, foods are rarely tested for viral contamination, and when done, testing is limited to shellfish commodities. In this work, we report a method to extract and detect human enteric viruses from alternative food commodities using an elution-concentration approach followed by detection using reverse transcription-polymerase chain reaction (RT-PCR). Fifty-gram lettuce or hamburger samples were artificially inoculated with poliovirus type 1 (PV1), hepatitis A virus (HAV), or the Norwalk virus and processed by the sequential steps of homogenization, filtration, Freon extraction (hamburger), and polyethylene glycol (PEG) precipitation. To reduce volumes further and remove RT-PCR inhibitors, a secondary PEG precipitation was necessary, resulting in an overall 10- to 20-fold sample size reduction from 50 g to 3 to 5 ml. Virus recoveries in secondary PEG concentrates ranged from 10 to 70% for PV1 and 2 to 4% for HAV as evaluated by mammalian cell culture infectivity assay. Total RNA from PEG concentrates was extracted to a small volume (30 to 40 microl) and subjected to RT-PCR amplification of viral RNA sequences. Detection limit studies indicated that viral RNA was consistently detected by RT-PCR at initial inoculum levels > or =102 PFU/50-g food sample for PV1 and > or =10(3) PFU/50-g food sample for HAV. In similar studies with the Norwalk virus, detection at inoculum levels > or =1.5 X 10(3) PCR-amplifiable units/50-g sample for both food products was possible. All RT-PCR amplicons were confirmed by subsequent Southern hybridization. The procedure reported represents progress toward the development of methods to detect human enteric viral contamination in foods other than shellfish.}, number={12}, journal={JOURNAL OF FOOD PROTECTION}, author={Leggitt, PR and Jaykus, LA}, year={2000}, month={Dec}, pages={1738–1744} }
 @article{jaykus_2000, title={Enteric viruses as 'emerging agents' of foodborne disease}, volume={39}, number={2}, journal={Irish Journal of Agricultural and Food Research}, author={Jaykus, L.}, year={2000}, pages={245–255} }
 @article{lucore_cullison_jaykus_2000, title={Immobilization with metal hydroxides as a means to concentrate food-borne bacteria for detection by cultural and molecular methods}, volume={66}, ISSN={["0099-2240"]}, DOI={10.1128/AEM.66.5.1769-1776.2000}, abstractNote={ABSTRACT The application of nucleic acid amplification methods to the detection of food-borne pathogens could be facilitated by concentrating the organisms from the food matrix before detection. This study evaluated the utility of metal hydroxide immobilization for the concentration of bacterial cells from dairy foods prior to detection by cultural and molecular methods. Using reconstituted nonfat dry milk (NFDM) as a model, two food-borne pathogens ( Listeria monocytogenes and Salmonella enterica serovar Enteritidis) were concentrated from 25-ml samples by the sequential steps of clarification and high-speed centrifugation (designated primary concentration) and immobilization with zirconium hydroxide and low-speed centrifugation (designated secondary concentration). Sample volume reduction after immobilization with zirconium hydroxide was 50-fold, with total bacterial recoveries ranging from 78 to 96% of input for serovar Enteritidis and 65 to 96% of input for L. monocytogenes . Immobilized bacteria remained viable and could be enumerated by standard cultural procedures. When followed by RNA extraction and subsequent detection by reverse transcription (RT)-PCR, detection limits of 10 1 to 10 2 CFU/25 ml of reconstituted NFDM were achieved for both organisms. The bacterial-immobilization step was relatively nonspecific, resulting in recovery of >50% of the input cells when evaluated on a panel of representative bacterial strains of significance to foods. The method could be adapted to more complex dairy products, such as whole milk and ice cream, for which bacterial recoveries after immobilization ranged from 64 to >100%, with subsequent RT-PCR detection limits of ≥10 2 CFU/ml for whole milk and ≥10 1 CFU for ice cream for both serovar Enteritidis and L. monocytogenes . The bacterial-immobilization method is easy, rapid, and inexpensive and may have applications for the concentration of a wide variety of food-borne bacteria prior to detection by both conventional and alternative methods.}, number={5}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Lucore, LA and Cullison, MA and Jaykus, LA}, year={2000}, month={May}, pages={1769–1776} }
 @article{koo_jaykus_2000, title={Modified method to detect PCR products by 5 ' nuclease activity and an asymmetric fluorogenic probe set}, volume={29}, ISSN={["0736-6205"]}, DOI={10.2144/00294bm03}, number={4}, journal={BIOTECHNIQUES}, author={Koo, K and Jaykus, LA}, year={2000}, month={Oct}, pages={690-+} }
 @article{vicari_morales_jaykus_cowen_2000, title={Revisiting dose-response models of foodborne pathogens}, journal={Proceedings of the 9th symposium of the International Society for Veterinary Epidemiology and Economics, Breckenridge, Colorado, USA, August 6-11 2000}, publisher={International Society for Veterinary Epidemiology and Economics (ISVEE)}, author={Vicari, A. S. and Morales, R. A. and Jaykus, L. A. and Cowen, P.}, year={2000}, pages={438} }
 @article{koo_jaykus_2000, title={Selective amplification of bacterial RNA: use of a DNA primer containing mismatched bases near its 3 ' terminus to reduce false-positive signals}, volume={31}, ISSN={["0266-8254"]}, DOI={10.1046/j.1365-2672.2000.00798.x}, abstractNote={A reverse transcription PCR (RT–PCR) method designed to reduce false‐positive results due to the co‐amplification of contaminating genomic DNA is reported. Feasibility of the method was evaluated using 16S rRNA sequences specific to Bacillus cereus. A DNA oligonucleotide primer, consisting of 22‐bases containing three consecutive mismatched bases near its 3′ terminus (primer B16RT), was used for reverse transcription and in subsequent cDNA amplification. Specific rRNA was reverse transcribed at low temperature (40 °C or 45 °C) in the presence of primer B16RT. As subsequent PCR using primer B16RT at high (62 °C) annealing temperatures is not nearly as efficient as amplification using the specific primer, amplification of genomic DNA was hindered relative to the amplification of cDNA. The method was readily adapted to the selective amplification of mRNA of the Listeria monocytogenes listeriolysin O (hly) gene.}, number={3}, journal={LETTERS IN APPLIED MICROBIOLOGY}, author={Koo, K and Jaykus, LA}, year={2000}, month={Sep}, pages={187–192} }
 @article{mcelroy_jaykus_foegeding_2000, title={Validation and analysis of modeled predictions of growth of Bacillus cereus spores in boiled rice}, volume={63}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-63.2.268}, abstractNote={The growth of psychrotrophic Bacillus cereus 404 from spores in boiled rice was examined experimentally at 15, 20, and 30 degrees C. Using the Gompertz function, observed growth was modeled, and these kinetic values were compared with kinetic values for the growth of mesophilic vegetative cells as predicted by the U.S. Department of Agriculture's Pathogen Modeling Program, version 5.1. An analysis of variance indicated no statistically significant difference between observed and predicted values. A graphical comparison of kinetic values demonstrated that modeled predictions were "fail safe" for generation time and exponential growth rate at all temperatures. The model also was fail safe for lag-phase duration at 20 and 30 degrees C but not at 15 degrees C. Bias factors of 0.55, 0.82, and 1.82 for generation time, lag-phase duration, and exponential growth rate, respectively, indicated that the model generally was fail safe and hence provided a margin of safety in its growth predictions. Accuracy factors of 1.82, 1.60, and 1.82 for generation time, lag-phase duration, and exponential growth rate, respectively, quantitatively demonstrated the degree of difference between predicted and observed values. Although the Pathogen Modeling Program produced reasonably accurate predictions of the growth of psychrotrophic B. cereus from spores in boiled rice, the margin of safety provided by the model may be more conservative than desired for some applications. It is recommended that if microbial growth modeling is to be applied to any food safety or processing situation, it is best to validate the model before use. Once experimental data are gathered, graphical and quantitative methods of analysis can be useful tools for evaluating specific trends in model prediction and identifying important deviations between predicted and observed data.}, number={2}, journal={JOURNAL OF FOOD PROTECTION}, author={McElroy, DM and Jaykus, LA and Foegeding, PM}, year={2000}, month={Feb}, pages={268–272} }
 @article{rosenfield_jaykus_1999, title={A multiplex reverse transcription polymerase chain reaction method for the detection of foodborne viruses}, volume={62}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-62.10.1210}, abstractNote={A multiplex reverse transcription polymerase chain reaction (RT-PCR) method was developed for the simultaneous detection of the human enteroviruses, hepatitis A virus (HAV) and Norwalk virus (NV). Poliovirus type 1 (PV1) was chosen as a model for the human enterovirus group. Three different sets of primers were used to produce three size-specific amplicons of 435 bp, 270 bp, and 192 bp for PV1, NV, and HAV, respectively. RT-PCR products were separated by agarose gel electrophoresis, and amplicon identity was confirmed by Southern transfer followed by DNA hybridization using nonradioactive, digoxigenin-labeled internal probes. When tested on mixed, purified virus suspensions, the multiplex method achieved detection limits of < or = 1 infectious unit (PV1 and HAV) or RT-PCR-amplifiable unit (NV) for all viruses. With further streamlining efforts such as single tube amplification and liquid hybridization, multiplex PCR offers advantages over cell culture methodology and monoplex PCR because it allows for rapid and cost-effective detection of several human enteric viruses in a single reaction tube.}, number={10}, journal={JOURNAL OF FOOD PROTECTION}, author={Rosenfield, SI and Jaykus, LA}, year={1999}, month={Oct}, pages={1210–1214} }
 @article{mcelroy_jaykus_foegeding_1999, title={A quantitative risk assessment for Bacillus cereus emetic disease associated with the consumption of Chinese-style rice}, volume={19}, ISSN={["1745-4565"]}, DOI={10.1111/j.1745-4565.1999.tb00246.x}, abstractNote={Journal of Food SafetyVolume 19, Issue 3 p. 209-229 A QUANTITATIVE RISK ASSESSMENT FOR BACILLUS CEREUS EMETIC DISEASE ASSOCIATED WITH THE CONSUMPTION OF CHINESE-STYLE RICE DANA M. McELROY, DANA M. McELROY Department of Food Science North Carolina State University Raleigh, NC 2 7695-7624Search for more papers by this authorLEE-ANN JAYKUS, LEE-ANN JAYKUS Department of Food Science North Carolina State University Raleigh, NC 2 7695-7624Search for more papers by this authorPEGGY M. FOEGEDING, PEGGY M. FOEGEDING Department of Food Science North Carolina State University Raleigh, NC 2 7695-7624Search for more papers by this author DANA M. McELROY, DANA M. McELROY Department of Food Science North Carolina State University Raleigh, NC 2 7695-7624Search for more papers by this authorLEE-ANN JAYKUS, LEE-ANN JAYKUS Department of Food Science North Carolina State University Raleigh, NC 2 7695-7624Search for more papers by this authorPEGGY M. FOEGEDING, PEGGY M. FOEGEDING Department of Food Science North Carolina State University Raleigh, NC 2 7695-7624Search for more papers by this author First published: 03 April 2007 https://doi.org/10.1111/j.1745-4565.1999.tb00246.xCitations: 18AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume19, Issue3October 1999Pages 209-229 RelatedInformation}, number={3}, journal={JOURNAL OF FOOD SAFETY}, author={McElroy, DM and Jaykus, LA and Foegeding, PM}, year={1999}, month={Oct}, pages={209–229} }
 @article{jaykus_ward_1999, title={An integrated approach: the future of graduate food safety education}, volume={19}, number={1}, journal={Dairy, Food and Environmental Sanitation}, author={Jaykus, L. A. and Ward, D. R.}, year={1999}, pages={14–17} }
 @article{mckillip_jaykus_drake_1999, title={Nucleic acid persistence in heat-killed Escherichia coli O157 : H7 from contaminated skim milk}, volume={62}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-62.8.839}, abstractNote={Polymerase chain reaction (PCR) and reverse transcriptase (RT)-PCR using primers targeting 16S rRNA sequences in Escherichia coli O157:H7 were applied to monitor the stability of rDNA and rRNA in cells killed by mild heat treatment (60 degrees C) in skim milk. Serial dilutions of purified RNA and DNA from E. coli O157:H7 in skim milk were amplified by RT-PCR or PCR, respectively, before heat treatment and at time points 0, 6, 12, 24, and 48 h after heating. In general, DNA-PCR provided stronger amplification signals compared to RT-PCR at the corresponding time points with the same PCR primer set, indicating a lower efficiency of RNA amplification compared to that of DNA. Ribosomal RNA and rDNA could be amplified by RT-PCR or PCR from both viable and dead cells throughout the 48-h posttreatment holding period. For RT-PCR, amplification signals decreased in intensity with increased holding time, while the efficiency of amplification of DNA sequences from dead cells remained fairly stable throughout the study. DNA persistence was greater than that of rRNA following cell death by mild heat treatment in skim milk. Skim milk did not appear to accelerate nucleic acid degradation. While rRNA was less stable than DNA, its detection by RT-PCR may not be appropriate as an exclusive indicator of cell viability in minimally processed foods.}, number={8}, journal={JOURNAL OF FOOD PROTECTION}, author={McKillip, JL and Jaykus, LA and Drake, M}, year={1999}, month={Aug}, pages={839–844} }
 @article{dombroski_jaykus_green_farkas_1999, title={Use of a mutant strain for evaluating processing strategies to inactivate Vibrio vulnificus in oysters}, volume={62}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-62.6.592}, abstractNote={Vibrio vulnificus is a ubiquitous marine bacterium frequently isolated from shellfish and associated with severe and often fatal disease in humans. Various control strategies to reduce the disease risk associated with V. vulnificus contamination in shellfish have been proposed. However, evaluating the efficacy of these control strategies is complicated because of the difficulty in distinguishing V. vulnificus from the high levels of background environmental Vibrio spp. The purpose of this research was to develop a model indicator V. vulnificus strain that could be readily differentiated from background microflora and used to facilitate the evaluation of processing efficacy. A spontaneous nalidixic acid-resistant strain of V. vulnificus (Vv-NA) was prepared from a wild-type parent (Vv-WT) using selective plating techniques. Vv-NA was very similar to Vv-WT with respect to biochemical characteristics, appearance on selective plating media, detection limits using most probable number and polymerase chain reaction, and growth rate. In comparative freeze inactivation studies on pure cultures, Vv-WT and Vv-NA had similar freeze inactivation profiles at -20 degrees C (conventional freezing), at -85 degrees C (cold blast freezing), and in liquid nitrogen (cryogenic freezing). In oyster homogenates artificially inoculated with Vv-NA, the organism was inactivated 95 to 99% after freezing, irrespective of freezing temperature. Thermal inactivation comparisons of pure cultures of Vv-WT and Vv-NA using the capillary tube method revealed statistically significant differences in D values at 47 degrees C (2.2 versus 3.0 min, respectively) and 50 degrees C (0.83 versus 0.56 min, respectively), but nearly identical values at 52 degrees C (0.21 versus 0.22 min, respectively). However, these D values were notably higher than those reported by other investigators and hence provided a conservative means by which to evaluate thermal inactivation. In oyster homogenates seeded with Vv-NA, D values of 1.3+/-0.09 min and 0.41+/-0.01 min were obtained at 46 degrees C and 48 degrees C, respectively. This study demonstrated that Vv-NA is readily enumerated and could be used as a surrogate for evaluating the degree of V. vulnificus inactivation provided by freezing and thermal treatments of oyster homogenates.}, number={6}, journal={JOURNAL OF FOOD PROTECTION}, author={Dombroski, CS and Jaykus, LA and Green, DP and Farkas, BE}, year={1999}, month={Jun}, pages={592–600} }
 @article{mckillip_jaykus_drake_1998, title={RNA stability in heat-killed and UV-irradiated enterotoxigenic Staphylococcus aureus and Escherichia coli O157: H7}, volume={64}, number={11}, journal={Applied and Environmental Microbiology}, author={McKillip, J. L. and Jaykus, L. A. and Drake, M.}, year={1998}, pages={4264–4268} }
 @article{dix_jaykus_1998, title={Virion concentration method for the detection of human enteric viruses in extracts of hard-shelled clams}, volume={61}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-61.4.458}, abstractNote={A method to extract and concentrate intact human enteric viruses from oyster extracts for detection using reverse transcription-polymerase chain reaction (RT-PCR) was applied to hard-shelled clams (mercenaria mercenaria). Fifty-gram clam samples were processed by an adsorption-elution-precipitation method and then seeded with 10(1) to 10(5) PFU to poliovirus 1 (PV1) and/or hepatitis A virus (HAV). Seeded viruses in extracts were purified by fluorocarbon (Freon) extraction and concentrated by polyethylene glycol (PEG) precipitation and elution. Efficiency of virion recovery from PEG precipitates was dependent upon PEG concentration and elution buffer volume, with optimized variable yielding recoveries as high as 99% for PV1 and 45% for HAV, as evaluated by cell culture infectivity assay. To further concentrate viruses, remove inhibitors, and reduce sample volumes, the protein-precipitating agent Pro-Cipitate was used in an adsorption-elution-precipitation scheme. The final concentrate was of low volume (< 1 ml) and directly compatible with viral genomic amplification using RT-PCR. When extracts from 50-g clam samples were seeded and processed by the combined concentration and purification scheme, direct RT-PCR detection of viral genomic RNA was possible at initial inoculum levels of 10(3) PFU for PV1 and HAV. Corresponding virus recoveries based on cell culture infectivity were 7 to 50% and 0.3 to 8% for pV1 and HAV, respectively, when extracts of clams were artificially contaminated with the Norwalk virus, direct detection of virion RNA using RT-PCR and subsequent oligoprobe hybridization was possible at levels as low as 450 RT-PCR amplifiable units of the Norwalk virus per extract of 50-g clam sample.}, number={4}, journal={JOURNAL OF FOOD PROTECTION}, author={Dix, AB and Jaykus, LA}, year={1998}, month={Apr}, pages={458–465} }
 @article{jaykus_1997, title={Epidemiology and detection as options for control of viral and parasitic foodborne disease}, volume={3}, ISSN={["1080-6059"]}, DOI={10.3201/eid0304.970418}, abstractNote={Human enteric viruses and protozoal parasites are important causes of emerging food and waterborne disease. Epidemiologic investigation and detection of the agents in clinical, food, and water specimens, which are traditionally used to establish the cause of disease outbreaks, are either cumbersome, expensive, and frequently unavailable or unattempted for the important food and waterborne enteric viruses and protozoa. However, the recent introduction of regulatory testing mandates, alternative testing strategies, and increased epidemiologic surveillance for food and waterborne disease should significantly improve the ability to detect and control these agents. We discuss new methods of investigating foodborne viral and parasitic disease and the future of these methods in recognizing, identifying, and controlling disease agents.}, number={4}, journal={EMERGING INFECTIOUS DISEASES}, author={Jaykus, LA}, year={1997}, pages={529–539} }
 @misc{jaykus_1996, title={The application of quantitative risk assessment to microbial food safety risks}, volume={22}, ISSN={["1040-841X"]}, DOI={10.3109/10408419609105483}, abstractNote={Regulatory programs and guidelines for the control of foodborne microbial agents have existed in the U.S. for nearly 100 years. However, increased awareness of the scope and magnitude of foodborne disease, as well as the emergence of previously unrecognized human pathogens transmitted via the foodborne route, have prompted regulatory officials to consider new and improved strategies to reduce the health risks associated with pathogenic microorganisms in foods. Implementation of these proposed strategies will involve definitive costs for a finite level of risk reduction. While regulatory decisions regarding the management of foodborne disease risk have traditionally been done with the aid of the scientific community, a formal conceptual framework for the evaluation of health risks from pathogenic microorganisms in foods is warranted. Quantitative risk assessment (QRA), which is formally defined as the technical assessment of the nature and magnitude of a risk caused by a hazard, provides such a framework. Reproducing microorganisms in foods present a particular challenge to QRA because both their introduction and numbers may be affected by numerous factors within the food chain, with all of these factors representing significant stages in food production, handling, and consumption, in a farm-to-table type of approach. The process of QRA entails four designated phases: (1) hazard identification, (2) exposure assessment, (3) dose-response assessment, and (4) risk characterization. Specific analytical tools are available to accomplish the analyses required for each phase of the QRA. The purpose of this paper is to provide a description of the conceptual framework for quantitative microbial risk assessment within the standard description provided by the National Academy of Sciences (NAS) paradigm. Each of the sequential steps in QRA are discussed in detail, providing information on current applications, tools for conducting the analyses, and methodological and/or data limitations to date. Conclusions include a brief discussion of subsequent uncertainty and risk analysis methodologies, and a commentary on present and future applications of QRA in the management of the public health risks associated with the presence of pathogenic microorganisms in the food supply.}, number={4}, journal={CRITICAL REVIEWS IN MICROBIOLOGY}, author={Jaykus, LA}, year={1996}, pages={279–293} }