@article{gradl_curtis_keener_macklin_norton_2016, title={Moisture content and moisture quantity of sweated chicken eggs in 2 storage environments}, volume={25}, ISSN={["1537-0437"]}, DOI={10.3382/japr/pfw027}, abstractNote={Abstract There are instances where shell eggs may be moved from refrigeration into ambient temperature with high humidity, such as before wash and during transportation. Under these conditions, it is of concern that bacteria on wet eggs can grow and migrate through the shell pores into the egg. Objectives of this experiment were: 1) to compare 3 methods of quantifying condensate on eggs and 2) to quantify condensate on refrigerated shell eggs at 2 temperatures (22°C and 32°C). For objective 1, 270 fresh shell eggs (3 replications, 90 eggs per replication) were stored at 4°C, 60% relative humidity (RH), then placed at 22°C, 60% RH for 1 h. After this time, 30 pre-weighed eggs were randomly selected and weighed. Thirty eggs were thoroughly wiped with pre-weighed paper towels to collect condensate. Thirty eggs were evaluated with a pinless moisture meter for quantifying egg condensate, which was found to be an ineffective method. There was no difference in quantifying egg condensation by egg weight or weight of moisture absorbed on a paper towel (0.2% vs. 0.19% percentage gain mL condensation/egg surface area) (P > 0.05). For objective 2, 104 fresh eggs formed condensation at 2 temperatures (22°C and 32°C, 60% RH). Each egg weight was continuously recorded from the beginning of condensation formation to the point where the egg reached a constant weight. There was a difference found in the time it took for an egg to reach maximum condensation (11 min at 32°C, 17 min at 22°C), as well as completely dry (25 min at 32°C, 34 min at 22°C) between the 2 temperatures (P}, number={3}, journal={JOURNAL OF APPLIED POULTRY RESEARCH}, author={Gradl, J. A. and Curtis, P. A. and Keener, K. M. and Macklin, K. S. and Norton, R. A.}, year={2016}, month={Sep}, pages={414–421} }
 @article{upadhyaya_upadhyay_kollanoor-johny_mooyottu_baskaran_yin_schreiber_khan_darre_curtis_et al._2015, title={In-Feed Supplementation of trans-Cinnamaldehyde Reduces Layer-Chicken Egg-Borne Transmission of Salmonella enterica Serovar Enteritidis}, volume={81}, ISSN={["1098-5336"]}, DOI={10.1128/aem.03809-14}, abstractNote={ABSTRACT Salmonella enterica serovar Enteritidis is a major foodborne pathogen in the United States, causing gastroenteritis in humans, primarily through consumption of contaminated eggs. Chickens are the reservoir host of S. Enteritidis. In layer hens, S. Enteritidis colonizes the intestine and migrates to various organs, including the oviduct, leading to egg contamination. This study investigated the efficacy of in-feed supplementation with trans-cinnamaldehyde (TC), a generally recognized as safe (GRAS) plant compound obtained from cinnamon, in reducing S. Enteritidis cecal colonization and systemic spread in layers. Additionally, the effect of TC on S. Enteritidis virulence factors critical for macrophage survival and oviduct colonization was investigated in vitro. The consumer acceptability of eggs was also determined by a triangle test. Supplementation of TC in feed for 66 days at 1 or 1.5% (vol/wt) for 40- or 25-week-old layer chickens decreased the amounts of S. Enteritidis on eggshell and in yolk (P < 0.001). Additionally, S. Enteritidis persistence in the cecum, liver, and oviduct in TC-supplemented birds was decreased compared to that in controls (P < 0.001). No significant differences in feed intake, body weight, or egg production in birds or in consumer acceptability of eggs were observed (P > 0.05). In vitro cell culture assays revealed that TC reduced S. Enteritidis adhesion to and invasion of primary chicken oviduct epithelial cells and reduced S. Enteritidis survival in chicken macrophages (P < 0.001). Follow-up gene expression analysis using real-time quantitative PCR (qPCR) showed that TC downregulated the expression of S. Enteritidis virulence genes critical for chicken oviduct colonization (P < 0.001). The results suggest that TC may potentially be used as a feed additive to reduce egg-borne transmission of S. Enteritidis.}, number={9}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Upadhyaya, Indu and Upadhyay, Abhinav and Kollanoor-Johny, Anup and Mooyottu, Shankumar and Baskaran, Sangeetha A. and Yin, Hsin-Bai and Schreiber, David T. and Khan, Mazhar I. and Darre, Michael J. and Curtis, Patricia A. and et al.}, year={2015}, month={May}, pages={2985–2994} }
 @article{mcmurtrie_kerth_bratcher_curtis_smith_2012, title={Marination with natural curing ingredients, storage time, and serving temperature effects on the sensory characteristics of forage-finished or commercially-sourced beef roasts}, volume={90}, ISSN={["1873-4138"]}, DOI={10.1016/j.meatsci.2011.11.006}, abstractNote={Beef inside round roasts (n=144) were cut from rounds obtained from both forage-finished cattle (n=72) and commercially-sourced beef (n=72). Roasts were portioned to weigh 0.45-0.68kg each. Each roast was then randomly assigned one of the following treatments: control, injected-no cure, or injected-cured. Additionally, roasts were assigned a serving temperature (hot or cold) and storage treatments (0d or 28d post cooking). Roasts from forage-fed beef had a more red interior color and higher shear values, and also retained more brine than commercially-sourced beef (P<0.05). Curing roasts improved TBARS values in roasts served hot and significantly reduced sensory warmed-over and grassy flavors (P<0.05). Marinating forage-finished beef roasts significantly improves tenderness and flavor characteristics.}, number={3}, journal={MEAT SCIENCE}, author={McMurtrie, K. E. and Kerth, C. R. and Bratcher, C. L. and Curtis, P. A. and Smith, B.}, year={2012}, month={Mar}, pages={747–754} }
 @article{thanissery_mcreynolds_conner_macklin_curtis_fasina_2010, title={Evaluation of the efficacy of NuPro yeast extract in reducing intestinal Clostridium perfringens levels in broiler chickens}, volume={89}, ISSN={["1525-3171"]}, DOI={10.3382/ps.2010-00879}, abstractNote={The etiological agent of necrotic enteritis is Clostridium perfringens. Traditionally, necrotic enteritis is controlled with in-feed antibiotics. However, increasing consumer demand for drug-free poultry has fostered the search for nonantibiotic alternatives. Yeast extract contain nucleotides that are immunomodulatory and also essential for cellular functions. An experiment was conducted to evaluate the efficacy of NuPro yeast extract (Alltech Inc., Nicholasville, KY) in reducing intestinal C. perfringens levels in broiler chickens. One hundred ninety-two 1-d-old male broiler chicks were obtained and randomly assigned to 6 treatments in a battery cage trial. Treatment 1 consisted of chicks fed a corn-soybean meal basal diet (BD) without added bacitracin methylene disalicylate or NuPro. Treatment 2 consisted of chicks fed BD into which bacitracin methylene disalicylate was added at 0.055 g/kg. Treatment 3 consisted of chicks fed BD supplemented with NuPro at a 2% level for the first 10 d of the experiment. Treatments 4 (PX), 5, and 6 (PN) consisted of chicks that were challenged with 3 mL of the C. perfringens inoculum (~10(7) cfu/mL) on d 14, 15, and 16 of the experiment and fed diets similar to treatments 1, 2, and 3, respectively. On d 1 and 7 postchallenge, intestinal C. perfringens levels, lesion scores, and alkaline phosphatase activity were assessed. On d 1 postchallenge, C. perfringens level in treatment 5 (2.09 log(10) cfu/g) was lower (P < 0.05) compared with the PX treatment (4.71 log(10) cfu/g) but similar to the PN treatment (2.98 log(10) cfu/g). A similar trend was observed on d 7 postchallenge. NuPro supplementation enhanced alkaline phosphatase activity (P < 0.05) in C. perfringens-challenged chicks and appeared to reduce intestinal lesion scores. Although dietary supplementation of NuPro in the PN treatment reduced C. perfringens levels by 1.73 and 0.68 log(10) cfu/g compared with the PX treatment on d 1 and 7 postchallenge, respectively, these reductions were not significant. Extending the period of NuPro supplementation beyond the first 10 d of life should be considered for achieving significant reduction in intestinal C. perfringensg levels.}, number={11}, journal={POULTRY SCIENCE}, author={Thanissery, R. and McReynolds, J. L. and Conner, D. E. and Macklin, K. S. and Curtis, P. A. and Fasina, Y. O.}, year={2010}, month={Nov}, pages={2380–2388} }
 @article{davis_curtis_conner_mckee_kerth_2008, title={Validation of cooking methods using shell eggs inoculated with Salmonella serotypes enteritidis and heidelberg}, volume={87}, ISSN={["1525-3171"]}, DOI={10.3382/ps.2007-00419}, abstractNote={Salmonella enterica serotype Enteritidis has long been associated with eggs, and more recently, Salmonella enterica serotype Heidelberg has also become associated with eggs. This study was undertaken to determine whether Salmonella Enteritidis and Salmonella Heidelberg are effectively eliminated from eggs by various cooking methods. Seven cooking methods were chosen--hard and soft cooked, scrambled, over easy, sunny-side up, poached, and free poached--and a pan insert and the free-flowing method were used. Shell eggs, purchased from a grocery store, were inoculated with Salmonella and cooked. The cooked eggs were analyzed by USDA-approved methods for Salmonella recovery. Findings indicated that existing cooking methods for the hard-cooked, soft-cooked, and poaching methods were safe. However, the same was not true for the current sunny-side-up, over-easy, and scrambled egg cooking methods.}, number={8}, journal={POULTRY SCIENCE}, author={Davis, A. L. and Curtis, P. A. and Conner, D. E. and McKee, S. R. and Kerth, L. K.}, year={2008}, month={Aug}, pages={1637–1642} }
 @article{curtis_2007, title={Microbiological challenges of poultry egg production in the US}, volume={63}, ISSN={["1743-4777"]}, DOI={10.1017/s0043933907001481}, abstractNote={Over the past 40 years there have been many changes in egg production and processing, as well as, the egg itself. Many of these changes have contributed to the microbial challenges of the egg that we face today. Salmonella enterica serovar Enteritidis (SE) and more recently Salmonella enterica serovar Heidelberg (SH) are the two organisms of most concern associated with eggs. Most U.S. egg producers utilize some type of control programme to ensure egg safety. Many use the United Egg Producers' “5-Start” Food Safety Programme. Commercial egg washing significantly reduced concentrations of aerobic bacteria, yeasts and moulds, Enterobacteriaceae, and E. coli on shell egg surfaces. However, refrigeration of eggs is often identified as one the most critical issues in minimizing the risks associated with Salmonella contamination in eggs. The condensation question always arises any time egg refrigeration is discussed. Moisture often condenses on the shell surface when cold eggs are moved from the cool storage into hot and/or humid conditions. Research has shown that the ability of any microbes present on the shell to penetrate the shell was not increased with egg sweating. Also, heat sensitivity of SE can be induced by exposure to low temperatures. Although low numbers of SE and SH can contaminate eggs via the transovarian or shell penetration route, these small numbers cannot be ignored. Storage at temperatures as low 4°C combined with natural defences does not completely prevent growth. Furthermore, rapid growth occurs at 25°C, so minimal temperature abuse could result in high levels of contamination within eggs. The need for proper management during production, properly controlled storage, cooking and serving is critical.}, number={2}, journal={WORLDS POULTRY SCIENCE JOURNAL}, author={Curtis, P.}, year={2007}, month={Jun}, pages={301–307} }
 @article{keener_mcavoy_foegeding_curtis_anderson_osborne_bush_2006, title={Effect of testing temperature on internal egg quality measurements}, volume={85}, ISSN={0032-5791}, url={http://dx.doi.org/10.1093/ps/85.3.550}, DOI={10.1093/ps/85.3.550}, abstractNote={The objective of this study was to determine the effect of egg testing temperature on quality measurements of shell eggs. The quality measurements compared included 3 Haugh unit (HU) devices (electronic Haugh, tripod Haugh, and Haugh meter), egg weight, albumen height, albumen width, albumen index, yolk width, yolk height, yolk index, percentage of thin albumen, and vitelline membrane strength at 3 temperatures of 5, 13, and 23 degrees C from 2 strains of laying hens (Hyline W36 and Bovans White) at 2 storage times. The HU measurements averaged 72.44 at time zero and 59.99 at 7 wk. At 7 wk for all devices, HU values decreased 6 units with increased temperature (P < 0.05). The electronic Haugh and tripod Haugh devices gave equal measurements for all testing conditions. The Haugh meter gave equal values at 5 degrees C for fresh eggs but lower HU at higher temperatures and 7 wk storage. Thus, it is recommended that egg testing temperature be reported when HU are measured. Coefficient of variation generally increased for all HU methods with increasing temperature. Although there was a proportionately different amount of thin albumen detected between the strains of laying hens, no significant difference was seen in HU. From the evaluated methods for measuring quality, the electronic Haugh, which electronically measures albumen height and calculates HU, provided the lowest coefficient of variation, was sensitive to quality loss, and gave the highest quality measurement (5 degrees C).}, number={3}, journal={Poultry Science}, publisher={Elsevier BV}, author={Keener, KM and McAvoy, KC and Foegeding, JB and Curtis, PA and Anderson, KE and Osborne, JA and Bush, DJ}, year={2006}, month={Mar}, pages={550–555} }
 @article{tharrington_curtis_kerth_2006, title={Evaluation of various cooking methods to ensure the safety of egg consumption}, ISBN={0392-0593}, number={1}, journal={Zootecnica International}, author={Tharrington, J. B. and Curtis, P. A. and Kerth, L. K.}, year={2006}, pages={56} }
 @article{jones_musgrove_caudill_curtis_2006, title={Frequency of Salmonella, Campylobacter, Listeria and Enterobacteriaceae detection in commercially cool water-washed shell eggs}, volume={26}, ISSN={["0149-6085"]}, DOI={10.1111/j.1745-4565.2006.00048.x}, abstractNote={The effect of cool water washing on shell egg temperature and pathogen detection was examined. Three temperature schemes were utilized in commercial dual washer systems: (1) HH = 48.9C, 48.9C; (2) HC = 48.9C, 23.9C; and (3) CC = 23.9C, 23.9C. HH eggs maintained the highest surface temperature (26.25C in-line, 20.25C off-line and 23.25C combined, P 0.05). The lowest temperatures were found in the CC eggs (21.25C in-line, 17.25C off-line and 19.25C combined). The frequency of Enterobacteriaceae detection in shell and membrane emulsions was greatest for the CC eggs (P 0.05 for in-line and combined). There was no difference in Enterobacteriaceae detection for the off-line facility. Salmonella was detected in three of 384 samples from the in-line facility. They were found in HC (2) and CC (1) shell emulsions. Two of 384 samples were positive for Campylobacter from the in-line facility (CC). Three wash water samples were positive for Listeria in the off-line facility (1 HC, 2 CC). No pathogens were detected in the egg contents during this study. The results of this study indicate that warm followed by cool water washing has the potential of decreasing egg temperature while maintaining surface microbiology at an acceptable level.}, number={4}, journal={JOURNAL OF FOOD SAFETY}, author={Jones, Deana R. and Musgrove, Michael T. and Caudill, A. Brooke and Curtis, Patricia A.}, year={2006}, month={Nov}, pages={264–274} }
 @article{jones_musgrove_caudill_curtis_northcutt_2005, title={Microbial Quality of Cool Water Washed Shell Eggs}, volume={4}, DOI={10.3923/ijps.2005.938.943}, abstractNote={3 Abstract: A study was conducted to examine the effects of cool water washing on the microbial quality of shell eggs. Six dual tank wash water temperature schemes were examined for their ability to reduce naturally occurring aerobic bacteria and inoculated Salmonella Enteritidis (SE). The wash water schemes were: T1= 48.9 C; T2 = 48.9 C, 23.9 C; T3 = 48.9 C, 15.6 C; T4 = 23.9 C; T5 = 15.6 C; and T6 = 23.9 C, 15.6 C. All wash o o o o o o o o o water tanks were maintained from 10.5-11.5 pH throughout the study. Eggs were exposed to the wash water temperature schemes in a pilot egg washer with recirculating wash water tanks. The total amount of time eggs were exposed to the wash water combinations was 60 s. Following washing, all eggs were sprayed with a 48.9 C, 200 ppm chlorine rinse solution. Eggs were stored and sampled for 9 wks. External aerobic o populations were lowest for T1 (typical U.S. wash water configuration), followed by T2 and T3. Aerobic surface contamination was greatest in T5 eggs. All treatments reduced SE levels in a similar manner as detected by shell and membrane emulsion and egg contents pools after enrichment. Commercial application of cool water shell egg processing will be investigated to determine the potential of thi s technology to enhance the safety and quality of shell eggs.}, number={12}, journal={International Journal of Poultry Science}, author={Jones, D.R. and Musgrove, M.T. and Caudill, A.B. and Curtis, P.A. and Northcutt, J.K.}, year={2005}, pages={938–943} }
 @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} }
 @misc{keener_bashor_curtis_sheldon_kathariou_2004, title={Comprehensive review of Campylobacter and poultry processing}, volume={3}, ISSN={["1541-4337"]}, DOI={10.1111/j.1541-4337.2004.tb00060.x}, abstractNote={Campylobacter has been recognized as a leading bacterial cause of human gastroenteritis in the United States, with 40000 documented cases annually. Epidemiological data suggest that contaminated products of animal origin, especially poultry, contribute significantly to campylobacteriosis. Thus, reduction of contamination of raw poultry would have a large impact in reducing incidence of illness. Contamination occurs both on the farm and in poultry slaughter plants. Routine procedures on the farm such as feed withdrawal, poultry handling, and transportation practices have a documented effect on Campylobacter levels at the processing plant. At the plant, defeathering, evisceration, and carcass chillers have been documented to cross-contaminate poultry carcasses. Carcass washings and the application of processing aids have been shown to reduce populations of Campylobacter in the carcasses by log10 0.5 log10 1.5; however, populations of Campylobacter have been shown to enter a poultry processing plant at levels between log10 5 colony-forming units (CFU)/mL and log10 8 CFU/mL of carcass rinse. The purpose of this article is to review Campylobacter, the infection that it causes, its association with poultry, contamination sources during processing, and intervention methods.}, number={2}, journal={COMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY}, author={Keener, KM and Bashor, MP and Curtis, PA and Sheldon, BW and Kathariou, S}, year={2004}, month={Apr}, pages={105–116} }
 @article{keener_anderson_curtis_foegeding_2004, title={Determination of cooling rates and carbon dioxide uptake in commercially processed shell eggs using cryogenic carbon dioxide gas}, volume={83}, ISSN={["0032-5791"]}, DOI={10.1093/ps/83.1.89}, abstractNote={The ability to rapidly cool shell eggs to 7 degrees C is important in the prevention of Salmonella Enteritidis (SE) growth. In addition, quality may also be maintained longer from rapid cooling of shell eggs. A commercial cryogenic CO2 egg cooling unit was designed and installed in a commercial egg processing facility. This unit was installed on a packer head to rapidly cool eggs individually prior to packaging. The objective of this study was to determine cooling rates and CO2 gas changes that result from rapidly cooling eggs using this commercial cryogenic egg cooling system and subsequent storage for 15 wk. Results indicated that cryogenic CO2 cooling quickly cooled shell eggs in approximately 45 min, whereas traditional cooling required from 19 to 116 h. CO2 uptake into the albumen was greater in cryogenically cooled eggs (2.11 mg/g) than in traditionally cooled eggs (1.81 mg/g) immediately after processing. No differences were observed in albumen CO2 content after 2 wk of storage; at 10 wk statistically greater CO2 content remained in the cryogenically cooled eggs (1.75 mg/g) compared with the traditionally cooled eggs (1.60 mg/g). These results suggest that a large amount of CO2 enters the egg during the cryogenic cooling process but is quickly lost during storage. Beyond 10 wk of storage, the albumen CO2 content in cryogenically cooled eggs was higher than in the traditionally cooled eggs suggesting chemical changes may have occurred in the albumen.}, number={1}, journal={POULTRY SCIENCE}, author={Keener, KM and Anderson, KE and Curtis, PA and Foegeding, JB}, year={2004}, month={Jan}, pages={89–94} }
 @article{bashor_curtis_keener_sheldon_kathariou_osborne_2004, title={Effects of carcass washers on Campylobacter contamination in large broiler processing plants}, volume={83}, ISSN={["1525-3171"]}, DOI={10.1093/ps/83.7.1232}, abstractNote={Campylobacter, a major foodborne pathogen found in poultry products, remains a serious problem facing poultry processors. Campylobacter research has primarily focused on detection methods, prevalence, and detection on carcasses; limited research has been conducted on intervention. The aim of this study was to assess the effectiveness of carcass washing systems in 4 large broiler-processing plants in removing Campylobacter species. Washing systems evaluated included combinations of inside/outside carcass washers and homemade cabinet washers. Processing aids evaluated were trisodium phosphate (TSP) and acidified sodium chlorite (ASC). The washer systems consisted of 1 to 3 carcass washers and used from 2.16 to 9.73 L of water per carcass. The washer systems used chlorinated water with 25 to 35 ppm of total chlorine. These washer systems on average reduced Campylobacter populations by log 0.5 cfu/mL from log 4.8 cfu/mL to log 4.3 cfu/mL. Washer systems with TSP or ASC reduced Campylobacter populations on average by an additional log 1.03 to log 1.26, respectively. Total average reductions in Campylobacter populations across the washer system and chill tank were log 0.76 cfu/mL. Washer systems that included antimicrobial systems had total average reductions in Campylobacter populations of log 1.53 cfu/mL. These results suggest that carcass washer systems consisting of multiple washers provide minimal reductions in Campylobacter populations found on poultry in processing plants. A more effective treatment of reducing Campylobacter populations is ASC or TSP treatment; however, these reductions, although significant, will not eliminate the organism from raw poultry.}, number={7}, journal={POULTRY SCIENCE}, author={Bashor, MP and Curtis, PA and Keener, KM and Sheldon, BW and Kathariou, S and Osborne, JA}, year={2004}, month={Jul}, pages={1232–1239} }
 @article{jones_curtis_anderson_jones_2004, title={Microbial contamination in inoculated shell eggs: II. Effects of layer strain and egg storage}, volume={83}, ISSN={["0032-5791"]}, DOI={10.1093/ps/83.1.95}, abstractNote={Three Ottawa control strains and a current commercial laying stock were reared and housed in the same environment. Eggs were collected at 5 different hen ages throughout the 2 production cycles of the flock. The eggs were inoculated with Salmonella Enteritidis (SE), Pseudomonas fluorescens (PF), a combination of the 2, or sterile buffered peptone water and stored up to 5 wk. After storage at room temperature, contamination levels were determined for the exterior surface, air cell, egg contents, and within the shell. Interior, egg contents, and shell contamination levels of SE and PF increased with storage time. There were no apparent increases in the infectivity of SE or PF in the presence of the other organism. PF was a poor survivor on the shell surface under these storage conditions. Throughout the 5-wk storage, eggs from control strain 10 maintained their microbial integrity more effectively. Eggs from control strain 5 and the current commercial stock were more easily contaminated than the other strains. These data suggest that genetic selection has altered microbiological defenses of the eggs produced.}, number={1}, journal={POULTRY SCIENCE}, author={Jones, DR and Curtis, PA and Anderson, KE and Jones, FT}, year={2004}, month={Jan}, pages={95–100} }
 @article{anderson_tharrington_curtis_jones_2004, title={Shell characteristics of eggs from historic strains of Single Comb White Leghorn chickens and the relationship of egg shape to shell strength}, volume={3}, ISBN={1682-8356}, DOI={10.3923/ijps.2004.17.19}, abstractNote={The effect of long term genetic selection on shell characteristics was determined by analyzing eggs acquired from Agriculture Canada: Ottawa Control Strain 5, from a 1950 base population; 7, from a 1959 population; and 10, from a 1972 population. H&N "Nick Chick" 1993 commercial strain was also included because it shares genetic ancestry with the three historic strains. Eggs were collected beginning at 28 wk of age, then every 4 wk through the end of the study at 86 wk of the laying cycle and egg weight, egg height, egg width, shell weight, shell thickness, egg specific gravity, and shell breaking force measured. The relationship of egg shape and weight as factors affecting shell strength were also investigated. Significant differences (P < 0.05) were found between strains for egg shape and a progressive increase in weight and surface area of eggs from the 1950 strain to the current strain. The shape index indicates that the current strain has increased egg size with the greatest increase seen in egg width. The mean breaking force of eggs from the current strain was higher (P< 0.05) than the other strain's eggs with no strain differences in percent shell weight, shell thickness, or specific gravity. A decline in breaking force, percent shell weight, and specific gravity was observed among all the strains over the production period. The results from this study suggest that genetic selection has produced larger eggs that are rounder in shape.}, number={1}, journal={International Journal of Poultry Science}, author={Anderson, Kenneth and Tharrington, J. B. and Curtis, P. A. and Jones, F. T.}, year={2004}, pages={17} }
 @article{musgrove_jones_northcutt_curtis_anderson_fletcher_cox_2004, title={Survey of shell egg processing plant sanitation programs: Effects on non-egg-contact surfaces}, volume={67}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-67.12.2801}, abstractNote={Sanitation standard operating procedures (SSOPs) are an integral component of process control and are often the first step in the implementation of food safety regulations. The objective of this study was to assess and compare the efficacies of sanitation programs used in a variety of shell egg processing facilities. In-line, off-line, and mixed operations were evaluated. Sixteen direct or indirect egg contact surfaces were sampled in various shell egg processing facilities in the southeast United States. Samples were collected at the end of a processing day (POST) and again the next morning before operations began (PRE). Total aerobic plate counts (APCs) were obtained and Enterobacteriacae were enumerated. No significant differences (P > 0.05) between POST and PRE bacterial counts were found for the 16 sampling sites. In general, high APCs were found on the wall of the recirculating water tank both POST and PRE. The APCs for the rewash belt were considerably high for all plants sampled. APCs were also high for the vacuum loaders. APCs for washers and washer brushes were relatively low for most plants sampled. PRE and POST levels of plant sanitation, as determined by direct microbial plating, did not differ significantly. At this point, it is difficult to draw definitive conclusions about how rigid SSOPs should be for the shell egg processing industry.}, number={12}, journal={JOURNAL OF FOOD PROTECTION}, author={Musgrove, MT and Jones, DR and Northcutt, JK and Curtis, PA and Anderson, KE and Fletcher, DL and Cox, NA}, year={2004}, month={Dec}, pages={2801–2804} }
 @article{jones_northcutt_musgrove_curtis_anderson_fletcher_cox_2003, title={Survey of Shell Egg Processing Plant Sanitation Programs: Effects on Egg Contact Surfaces}, volume={66}, ISSN={0362-028X 1944-9097}, url={http://dx.doi.org/10.4315/0362-028x-66.8.1486}, DOI={10.4315/0362-028X-66.8.1486}, abstractNote={To successfully implement a hazard analysis critical control point plan, prerequisite programs are essential. Sanitation standard operating procedures are an important part of such a plan and can reduce contamination levels so that food safety and quality are not adversely affected. Noncontact surfaces in the shell egg processing plants can serve as a reservoir of cross-contamination. The objective of this study was to assess the efficacy of sanitation programs used in a variety of shell egg processing facilities (in-line, off-line, and mixed operations). Fourteen different noncontact surfaces were sampled in nine commercial facilities across the southeastern United States. Non-egg-contact surfaces were defined as those where the shell egg does not come into direct contact with the surface or with the fluid from that surface. Gauze pads soaked in sterile phosphate-buffered saline were used for sampling at the end of a processing day (POST) and again the next morning prior to operations (PRE). Aerobic plate counts (APCs) and numbers of Enterobacteriaceae were determined. No significant differences (P > 0.05) were found between POST and PRE counts for either population recovered from the 14 sampling sites. Only samples from the floor under the farm belts, nest-run loader, washers, and packer heads were reduced by 1 log CFU/ml of rinsate for APCs or Enterobacteriaceae counts. APCs of more than 10(4) CFU/ml of rinsate were recovered from many samples. Highest APCs were found on the floor under the farm belt and on shelves of the nest-run carts. High APCs were found on the wheel surface for off-line carts and on the loading dock floor. Highest Enterobacteriaceae counts were found in samples from the floor, drain, and nest-run egg cart shelves. A lack of significant difference between POST and PRE counts indicates that current sanitation programs could be improved. These data suggest that traffic patterns for the movement of eggs and materials through the plant should be reevaluated so that cross-contamination is reduced.}, number={8}, journal={Journal of Food Protection}, publisher={International Association for Food Protection}, author={Jones, D. R. and Northcutt, J. K. and Musgrove, M. T. and Curtis, P. A. and Anderson, K. E. and Fletcher, D. L. and Cox, N. A.}, year={2003}, month={Aug}, pages={1486–1489} }
 @article{sabliov_farkas_keener_curtis_2002, title={Cooling of shell eggs with cryogenic carbon dioxide: a finite element analysis of heat transfer}, volume={35}, DOI={10.1006/fstl.2002.0915}, abstractNote={Cryogenic carbon dioxide cooling of shell eggs was simulated using an axisymmetric unsteady state finite element heat transfer model. The egg was assumed to be a composite system of elliptical shape, consisting of yolk, albumen, air cell, and shell, each isotropic. An enthalpy formulation of the heat transfer problem was used to account for ice formation and growth in the region between the albumen and the shell during cooling. Simulated temperature profiles were compared with analytical and observed data and showed good agreement. The numerical simulation was used to gain an understanding of the two processes encompassed by cryogenic cooling, rapid cooling and equilibration.}, number={7}, journal={Food Science & Technology = Lebensmittel-Wissenschaft & -Technologie}, author={Sabliov, C. M. and Farkas, B. E. and Keener, K. M. and Curtis, P. A.}, year={2002}, pages={568–574} }
 @article{jones_tharrington_curtis_anderson_keener_jones_2002, title={Effects of cryogenic cooling of shell eggs on egg quality}, volume={81}, ISSN={["0032-5791"]}, DOI={10.1093/ps/81.5.727}, abstractNote={This study was conducted to investigate the effects of cryogenic cooling on shell egg quality. Gaseous nitrogen (GN), liquid nitrogen (LN), and gaseous carbon dioxide (GC) were utilized to rapidly cool eggs in a commercial egg processing facility and were compared to traditional cooling (TC). A modified food freezer was attached to existing egg processing equipment in order to expose eggs to the selected cryogen. In Experiment 1, eggs were treated with GN, LN, and TC then stored and tested over 10 wk. Experiment 2 eggs were treated (GC and TC) and evaluated for 12 wk. Quality factors that were measured included Haugh units, vitelline membrane strength and deformation at rupture, and USDA shell egg grades for quality defects. Haugh unit values were greater for cryogenically treated eggs as compared to traditionally cooled eggs (Experiment 1: 73.27, GN; 72.03, LN; and 71.4, TC and Experiment 2: 74.42, GC and 70.18, TC). The percentage of loss eggs in the GN treatment was significantly (P < 0.01) greater than those of the LN and TC treatments. Vitelline membrane strength was greater for the cryogenically cooled eggs versus traditional processing. Vitelline membrane breaking strength decreased over storage time. Vitelline membrane deformation at rupture was significantly (P < 0.05) greater for the cryogenically cooled eggs compared to the traditional eggs in each experiment. Use of the technology could allow for egg quality to be maintained for a longer time, which could increase international markets and potentially lead to extended shelf lives.}, number={5}, journal={POULTRY SCIENCE}, author={Jones, DR and Tharrington, JB and Curtis, PA and Anderson, KE and Keener, KM and Jones, FT}, year={2002}, month={May}, pages={727–733} }
 @article{jones_anderson_curtis_jones_2002, title={Microbial contamination in inoculated shell eggs: I. Effects of layer strain and hen age}, volume={81}, ISSN={["0032-5791"]}, DOI={10.1093/ps/81.5.715}, abstractNote={Three Ottawa control strains and a current commercial laying stock were reared and housed under identical environmental and management conditions. Eggs were collected from each strain when hens were 32, 45, 58, 71, and 84 wk of age. The eggs were inoculated with Salmonella enteritidis (SE), Pseudomonasfluorescens (PF), or a combination of the two. After storage at 26 C, bacterial counts were obtained from the exterior shell surfaces (rinse), air cell, egg contents, and shell structure. SE and PF survived at different rates on the shell surface with as much as a 1 log difference during a given collection period. Egg content counts tended to be higher than eggshell counts in PF, whereas the opposite was true for SE. These data suggest that PF is a primary invader of eggs that is more capable of contaminating egg contents through the shell membranes than SE. The PF and SE data suggest that bacterial contamination of air cells, shells, and egg contents is more easily achieved in eggs from older hens than from younger hens. There were also differences between the strains. Control Strain 10 consistently maintained a lower level of contamination for both organisms in each sampling location. The overall results of this study suggest that genetic selection has altered the ability of eggs to resist microbial contamination and that screening for microbial integrity should be considered in the selection process among the laying egg breeders.}, number={5}, journal={POULTRY SCIENCE}, author={Jones, DR and Anderson, KE and Curtis, PA and Jones, FT}, year={2002}, month={May}, pages={715–720} }
 @article{sabliov_farkas_keener_curtis_2002, title={Parametric analysis of cryogenic carbon dioxide cooling of shell eggs}, volume={81}, ISSN={["1525-3171"]}, DOI={10.1093/ps/81.11.1758}, abstractNote={Parametric analysis of cryogenic cooling of shell eggs was performed using finite element analysis. Two cooling temperatures (-50 and -70 C), three cooling convective heat transfer coefficients (20, 50, and 100 W/ m2K), two equilibration temperatures (7 and 25 C), and two equilibration heat transfer coefficients (0 and 20 W/ m2K) were considered in the analysis. Lower temperatures and higher cooling convective heat transfer coefficients resulted in higher cooling rates and lower final egg temperatures. A chart and equation were developed to identify combinations of processing parameters to yield the desired egg temperature (7 C) at the end of adiabatic equilibration. Results show that a cooling time of 8.2 min was required to reach a final egg temperature of 7 C for a cooling temperature of -50 C and a convective heat transfer coefficient of 20 W/m2K. The cooling time decreased to 2 min when the convective heat transfer coefficient increased to 100 W/m2K, at a cooling temperature of -50 C. Processing at -70 C and 20 W/m2K, required 5.3 min to reach a final temperature of 7 C. At a higher convective heat transfer coefficient (100 W/m2K) and -70 C, a processing time of 1.3 min was sufficient to reach the target temperature of 7 C. The results may be used as a reference in process or equipment design for shell egg cooling in cryogenic CO2.}, number={11}, journal={POULTRY SCIENCE}, author={Sabliov, CM and Farkas, BE and Keener, KM and Curtis, PA}, year={2002}, month={Nov}, pages={1758–1765} }
 @article{keener_lacrosse_farkas_curtis_anderson_2000, title={Gas exchange into shell eggs from cryogenic cooling}, volume={79}, ISSN={["0032-5791"]}, DOI={10.1093/ps/79.2.275}, abstractNote={The gas composition of the air cell in a shell egg is influenced by heating from egg washing and candling and the method of cooling and storage. This study found that N2 gas (-122 C), CO2 gas (-45 C), and cold air (-15 C) could be used to rapidly cool shell eggs from 47.7 C to 7 C in 30 min or less. These results suggest that the gas composition of the air cell in shell eggs can be significantly modified using N2 cooling and CO2 cooling. Commercial field studies have shown that these modifications, which take place during cryogenic cooling, can significantly reduce microbial levels and increase shelf life of shell eggs. Storage in a modified atmosphere environment further enhanced these changes. It was found that the CO2 concentration in the air cell of a shell egg can be increased from 0.04 to 48% by CO2 cooling and storage in a CO2 environment.}, number={2}, journal={POULTRY SCIENCE}, author={Keener, KM and Lacrosse, JD and Farkas, BE and Curtis, PA and Anderson, KE}, year={2000}, month={Feb}, pages={275–280} }
 @article{keener_lacrosse_curtis_anderson_farkas_2000, title={The influence of rapid air cooling and carbon dioxide cooling and subsequent storage in air and carbon dioxide on shell egg quality}, volume={79}, ISSN={["0032-5791"]}, DOI={10.1093/ps/79.7.1067}, abstractNote={This study examined the effect of rapid cooling with air and CO2 on shell egg quality over 14 wk. The 240 fresh eggs were initially heated to 47 C for 24 h in an incubator, cooled using rapid air cooling or CO2 cooling, and then stored in air or CO2 in 250-mL jars for 14 wk. The CO2 levels were recorded of the jar atmosphere, of the egg air cell, and of the egg albumen. The Haugh units of each egg, pH, and of albumen from five eggs per group were also recorded. Haugh units are a logarithmic, empirical relationship between albumen height and egg weight (Stadelman, 1995). Haugh units for the control eggs averaged 70.8 over 10 wk of the study. The control eggs were of such poor quality that they could not be sampled after 10 wk. The air-cooled and CO2-stored eggs averaged 70.3 Haugh units over the 14-wk storage period; however, the egg quality significantly deteriorated after 10 wk. The CO2-cooled and CO2-stored eggs averaged 75.9 Haugh units over the 14 wk study, with no observable decrease in quality. Rapid air-cooling produces a lower quality egg than rapid cooling with CO2. Subsequent storage of rapidly air-cooled eggs in C02 may increase shelf life, but Haugh units were not statistically different from rapid air-cooled eggs. CO2-cooling and subsequent storage in CO2 increased Haugh units. The shelf life of shell eggs could be extended to greater than 14 wk when the eggs were CO2-cooled and CO2-stored.}, number={7}, journal={POULTRY SCIENCE}, author={Keener, KM and LaCrosse, JD and Curtis, PA and Anderson, KE and Farkas, BE}, year={2000}, month={Jul}, pages={1067–1071} }
 @article{tharrington_curtis_jones_anderson_1999, title={Comparison of physical quality and composition of eggs from historic strains of single comb white leghorn chickens}, volume={78}, DOI={10.1093/ps/78.4.591}, abstractNote={The effect of long-term genetic selection on physical quality and composition of eggs was determined by analyzing eggs acquired from Agriculture Canada: Ottawa Control Strain 5 (CS5) from a 1950 base population, 7 (CS7) from a 1958 population and 10 (CS10) from a 1972 population. Eggs from the H&N "Nick Chick" current commercial strain (CCS) were also included. Eggs were collected monthly over a 62-wk laying period and analyzed for egg, albumen, shell and yolk weight; albumen protein, solids and pH; percentage yolk solids and fat; Haugh units; and specific gravity. Significant (P < 0.05) differences found between strains included a progressive increase in weight of eggs from the CS5 to CCS. Although the eggs increased in size, no significant differences were found between strains for specific gravity or percentage shell weight. Yolk weights of eggs from the strains examined did not differ. However, the percentage of yolk found in current strain eggs was significantly lower (P < 0.05), with a subsequent higher percentage albumen due to the increase in egg size of the CCS. Haugh units were significantly higher in the CS10 and CCS strains than in the other strains. No significant differences between strains were seen in albumen protein, solids, pH, or yolk solids. Mean percentage yolk fat assay values for eggs from the CS5, CS7, CS10, and CCS strains were 33.08, 32.68, 32.84, and 32.40, respectively. Percentage yolk fat values obtained from CCS were significantly lower (P < 0.05) than those obtained from the other strains. The results from this study indicate that genetic selection has produced larger eggs containing a lower percentage of yolk while overall egg quality has been maintained or improved.}, number={4}, journal={Poultry Science}, author={Tharrington, J. B. and Curtis, P. A. and Jones, F. T. and Anderson, Kenneth}, year={1999}, pages={591–594} }
 @article{taylor_curtis_1999, title={Development and design of a "Gateway" to food safety information on the internet for extension educators}, volume={37}, number={2}, journal={Journal of Extension}, author={Taylor, M. C. and Curtis, P.A.}, year={1999} }
 @inbook{zeidler_curtis_nambudiripad_1998, title={Food microbiology and refrigeration}, booktitle={ASHRAE handbook CD. Refrigeration (I-P and SI ed.)}, publisher={Atlanta: ASHRAE}, author={Zeidler, G. and Curtis, P. A. and Nambudiripad, G. P.}, year={1998} }
 @inbook{zeidler_curtis_hendrickson_vallort_1998, title={Meat products}, booktitle={ASHRAE handbook CD. Refrigeration (I-P and SI ed.)}, publisher={Atlanta: ASHRAE}, author={Zeidler, G. and Curtis, P. A. and Hendrickson, R. L. and Vallort, R. P.}, year={1998} }
 @inbook{zeidler_curtis_1998, title={Poultry products}, booktitle={ASHRAE handbook CD. Refrigeration (I-P and SI ed.)}, publisher={Atlanta: ASHRAE}, author={Zeidler, G. and Curtis, P. A.}, year={1998} }
 @article{sheldon_curtis_dawson_ferket_1997, title={Effect of dietary vitamin E on the oxidative stability, flavor, color, and volatile profiles of refrigerated and frozen turkey breast meat}, volume={76}, ISSN={["0032-5791"]}, DOI={10.1093/ps/76.4.634}, abstractNote={In this study, the effect of varying dietary vitamin E levels on the oxidative stability, flavor, color, and volatile profiles of refrigerated and frozen turkey breast meat was examined. Nicholas turkey toms were reared on diets containing vitamin E levels as dl-alpha-tocopheryl acetate equivalent to the NRC recommendations (12 and 10 IU/kg from 0 to 8 and 9 to 18 wk, respectively) and 5x, 10x, and 25x the NRC diet. Two other diets were evaluated and included feeding the NRC diet until 15 and 16 wk followed by a diet containing 20x the NRC vitamin E level. All turkeys were processed in a commercial turkey processing plant and breast meat scored for color. Breast meat was excised from four carcasses per treatment and evaluated after refrigeration (1 and 7 d) or frozen storage (30, 90, 150 d) for oxidative stability and sensory quality by TBA analysis, descriptive flavor profiling, and headspace gas chromatography. The TBA values were inversely related to the dietary vitamin E levels. Refrigerated samples had TBA values 78 to 88% lower for the 10x and 25x vitamin E treatments, respectively, than for the NRC control treatment. No differences in TBA values (refrigerated samples) were detected for the 10x, 25x, and 20x (3 wk feeding duration) or across all treatments for samples frozen for 5 mo. The 10x and 25x NRC diets produced the most typical and acceptable turkey meat flavors with the fewest oxidized off-flavor notes for both fresh and frozen samples as opposed to the more oxidized flavor notes detected in the control samples. Mean color scores increased, indicative of less pale meat, as the level and duration of feeding dietary vitamin E increased. These findings showed that varying dietary vitamin E levels significantly influenced the oxidative stability and functionality of turkey breast meat.}, number={4}, journal={POULTRY SCIENCE}, author={Sheldon, BW and Curtis, PA and Dawson, PL and Ferket, PR}, year={1997}, month={Apr}, pages={634–641} }
 @article{lucore_jones_anderson_curtis_1997, title={Internal and external bacterial counts from shells of eggs washed in a commercial-type processor at various wash-water temperatures}, volume={60}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028x-60.11.1324}, abstractNote={The effects of two egg holding temperatures (15.5 and 26.7°C) and three wash-water temperatures (15.5, 32.2, and 48.9°C) on internal and external shell surface bacterial counts were tested by using a commercial-type egg-processing unit. Two experiments consisting of five trials, each of which included 360 eggs per treatment for a total of 2,160 per trial, were conducted during two seasons (summer and winter) for a total of 10 replicates per experiment. During the performance of each replicate, counts from tryptic soy agar (TSA) and MacConkey agar (MAC) were obtained from 10 egg samples which were collected prior to processing (prewash), immediately after washing (postwash), and after as-day cooling period at 7.2°C (postcool). No growth was observed on MAC plates in either experiment, indicating that fewer than 100 counts were detected. No significant differences (P > 0.05) were observed in the prewash, postwash, or postcool internal shell counts of eggs held at l5.5°C compared to internal counts of shells of eggs held at 26.7°C. Likewise, no significant differences (P > 0.05) were observed in the prewash, postwash, or postcool internal shell counts obtained from eggs washed in l5.5°C water compared with internal shell counts obtained from eggs washed in water at 32.2 or 48.9°C. On the basis of our data, spray washing eggs in l5.5°C water does not appear to increase internal shell bacterial counts. Because warm or hot wash water increases egg temperatures markedly, a reexamination of cold-water processing procedures may be in order.}, number={11}, journal={JOURNAL OF FOOD PROTECTION}, author={Lucore, LA and Jones, FT and Anderson, KE and Curtis, PA}, year={1997}, month={Nov}, pages={1324–1328} }
 @article{curtis_anderson_jones_1997, title={Plan de HACCP para plantas de clasificacion de huevos}, volume={44}, number={10}, journal={Industria Avicola}, author={Curtis, P.A. and Anderson, K.E. and Jones, F.T.}, year={1997}, pages={10–12} }
 @article{curtis_anderson_jones_1995, title={Cryogenic Gas for Rapid Cooling of Commercially Processed Shell Eggs Before Packaging}, volume={58}, ISSN={0362-028X 1944-9097}, url={http://dx.doi.org/10.4315/0362-028x-58.4.389}, DOI={10.4315/0362-028x-58.4.389}, abstractNote={Research was initiated to evaluate the effects on egg quality and microbial counts of rapidly cooling eggs by using cryogenic gases. Four trials were conducted utilizing a 2 × 2 factorial design with cryogenic cooling and Pseudomonas inoculation as the main variables. The 1440 eggs used in each trial were evaluated for cracked shells, Haugh units, and albumen pH. Cryogenically cooled treatment groups were successfully cooled from 37°C to 7°C in significantly less time than in a traditionally cooled pallet. The Haugh unit values obtained from traditionally cooled eggs were significantly (P > .001) lower than those from cryogenically cooled eggs. There was no significant difference in the albumen pH of the two groups. Internal and external bacterial counts revealed significantly fewer bacteria in the interior of cryogenically cooled eggs than in the interior of traditionally cooled eggs. However, after a 30-day storage period at 7°C, no difference was found in external and internal bacterial contamination rates. The results of this trial suggest that rapid cooling with cryogenic gases could be used in conjunction with current commercial egg processing to cool eggs prior to packaging. The successful commercial application of this procedure would reduce egg temperatures as well as the likelihood of Salmonella enteritidis growth in or on eggs. Thus, consumers would be provided with safer commercially processed shell eggs. In addition, the Haugh unit data indicate that rapid cooling with cryogenic gases enhances the quality of commercially processed shell eggs.}, number={4}, journal={Journal of Food Protection}, publisher={International Association for Food Protection}, author={Curtis, Patricia A. and Anderson, Kenneth E. and Jones, Frank T.}, year={1995}, month={Apr}, pages={389–394} }
 @misc{anderson_curtis_jones_1995, title={Rapid chilling of shell eggs using cryogenic gases}, volume={5474794}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Anderson, K. E. and Curtis, P. A. and Jones, F. T.}, year={1995} }
 @article{curtis_gardner_mellor_1986, title={A COMPARISON OF SELECTED QUALITY AND COMPOSITIONAL CHARACTERISTICS OF BROWN AND WHITE SHELL EGGS .3. COMPOSITION AND NUTRITIONAL CHARACTERISTICS}, volume={65}, ISSN={["0032-5791"]}, DOI={10.3382/ps.0650501}, abstractNote={Abstract Eggs were obtained from three brown and three white shell commercial layer strains during 12 28-day production periods. Forty-eight eggs were randomly selected from each of the six strains during the last week of each period. The 61.5-g average egg weight for the brown shell eggs was significantly greater than the 60.3-g average weight of the white shell eggs. Significant differences were also found for the component parts. The overall means for percent shell were 9.35 and 8.65, for percent yolk 27.6 and 26.8, and for percent albumen 63.1 and 64.5 for the white shell eggs and the brown shell eggs, respectively. The only significant difference found in chemical composition was the percentage of albumen solids, which was 11.2 for the brown shell eggs and 10.8 for the white shell eggs.}, number={3}, journal={POULTRY SCIENCE}, author={CURTIS, PA and GARDNER, FA and MELLOR, DB}, year={1986}, month={Mar}, pages={501–507} }
 @article{curtis_gardner_litzenberg_1986, title={Measuring computer literacy in colleges of agriculture:  conclusions and implications}, volume={30}, number={4}, journal={NACTA Journal}, author={Curtis, P.A. and Gardner, F.A. and Litzenberg, K.K.}, year={1986}, pages={18–24} }
 @article{curtis_gardner_mellor_1985, title={A COMPARISON OF SELECTED QUALITY AND COMPOSITIONAL CHARACTERISTICS OF BROWN AND WHITE SHELL EGGS .1. SHELL QUALITY}, volume={64}, ISSN={["1525-3171"]}, DOI={10.3382/ps.0640297}, abstractNote={Abstract This paper compares interior quality measurements from three brown and three white shell commercial layer strains. Eggs were obtained during twelve 28-day production periods. Forty-eight eggs were randomly selected from each of the six strains during the last week of each period. Individual interior quality measurements were then taken. Significant differences were found in Haugh units, albumen indexes, and albumen pH measurements for the two color groups. The overall means for Haugh units were 85.11 and 81.92, for albumen indexes .1027 and .0938, and albumen pH 7.98 and 8.04 for the brown and white shell eggs, respectively. Yolk indexes for the shell color groups were .504 for brown shell eggs and .509 for white shell eggs and did not differ significantly.}, number={2}, journal={POULTRY SCIENCE}, author={CURTIS, PA and GARDNER, FA and MELLOR, DB}, year={1985}, pages={297–301} }
 @article{curtis_gardner_mellor_1985, title={A COMPARISON OF SELECTED QUALITY AND COMPOSITIONAL CHARACTERISTICS OF BROWN AND WHITE SHELL EGGS .2. INTERIOR QUALITY}, volume={64}, ISSN={["0032-5791"]}, DOI={10.3382/ps.0640302}, abstractNote={This paper compares interior quality measurements from three brown and three white shell commercial layer strains. Eggs were obtained during twelve 28-day production periods. Forty-eight eggs were randomly selected from each of the six strains during the last week of each period. Individual interior quality measurements were then taken. Significant differences were found in Haugh units, albumen indexes, and albumen pH measurements for the two color groups. The overall means for Haugh units were 85.11 and 81.92, for albumen indexes .1027 and .0938, and albumen pH 7.98 and 8.04 for the brown and white shell eggs, respectively. Yolk indexes for the shell color groups were .504 for brown shell eggs and .509 for white shell eggs and did not differ significantly.}, number={2}, journal={POULTRY SCIENCE}, author={CURTIS, PA and GARDNER, FA and MELLOR, DB}, year={1985}, pages={302–306} }