@article{breidt_2023, title={BufferCapacity3 an interactive GUI program for modelling food ingredient buffering and pH}, volume={22}, ISSN={["2352-7110"]}, DOI={10.1016/j.softx.2023.101351}, abstractNote={For many acidic foods, including fermented and acidified vegetables, salsas, salad dressings, and others, maintaining a pH below 4.6 is a critical control to prevent botulism. The pH of acidic foods is controlled by acid content, low acid ingredients, and buffering; however, buffering of foods remains largely uncharacterized. A Matlab GUI program “BufferCapacity3” was developed to automate the process of quantifying the buffers present in foods utilizing acid/base titration data. The BufferCapacity3 program may be used to aid product development and help assure pH control and safety of acidic foods.}, journal={SOFTWAREX}, author={Breidt, Fred}, year={2023}, month={May} }
 @article{breidt_skinner_shriner_ruinsky_yang_wine_johnston_2023, title={IngredientDB: A GUI-based Matlab database program for estimating the pH of acid or acidified food formulations from buffer capacity models}, volume={24}, ISSN={["2352-7110"]}, DOI={10.1016/j.softx.2023.101545}, abstractNote={A Matlab GUI program, IngredientDB, was developed to help determine the pH and buffering of ingredients in acidic food products based on product formulations. A database of buffer capacity models for both low acid and acid food ingredients was developed and used to show how individual food ingredients influence the final product pH. The IngredientDB program may be used for in silico formulations of acidic food products to help assure the quality and safety of these foods.}, journal={SOFTWAREX}, author={Breidt, Fred and Skinner, Caitlin R. and Shriner, Mileah and Ruinsky, Mollie and Yang, Seo Young and Wine, Robert P. and Johnston, Lynette}, year={2023}, month={Dec} }
 @article{fragedakis_skinner_shriner_ruinsky_yang_wine_johnston_breidt_2023, title={Modeling the formulation pH of elderberry syrup with multiple weak acids}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.16664}, abstractNote={The objective of this work was to develop methods to assess the influence of the ingredients of an acidified elderberry syrup on product pH. A measure of total ingredient buffering (tBeta) was defined as the area under the buffer capacity curve of a food mixture or ingredient for pH 2-12. Citric acid (1% w/v), elderberry juice (75% v/v), and malic acid (0.75% w/v) had greater buffering (tBeta values of 15.33, 12.00, and 10.95, respectively) than ascorbic acid (0.75%) or lemon juice (3% v/v) (tBeta of 5.74 and 3.30, respectively). All other ingredients, including added spices (≤1% each) and honey (25% w/v), had tBeta values <2. The observed pH for the syrup mixture (pH 2.67) was within 0.11 pH units of the predicted pH based on combined buffer models of the acid and low acid ingredients (pH 2.78) using Matlab software. A total of 16 model syrup formulations containing elderberry juice with mixed acids (malic, acetic, and ascorbic) and having pH values between 3 and 4 were prepared. The pH values of the formulations were compared to predicted values from combined buffer models of the individual ingredients. Regression analysis indicated an excellent fit of the observed and predicted pH data, with a root mean square error of 0.076 pH units. The results indicated that buffer models may be useful for in silico estimates of how the ingredients in acid and acidified foods may influence pH, thus aiding in product development and safety assessments. PRACTICAL APPLICATION: Buffer models using recently developed titration methods for individual acid and low-acid food ingredients can be used to estimate the pH of formulations of these ingredients in silico. The total buffering (tBeta) for ingredients or mixtures, along with ingredient concentrations, may be a useful metric for helping to determine which ingredients will have the greatest impact on pH. Such models can aid product development efforts and safety assessments.}, journal={JOURNAL OF FOOD SCIENCE}, author={Fragedakis, Nicholas and Skinner, Caitlin R. R. and Shriner, Mileah and Ruinsky, Mollie and Yang, Seo Young and Wine, Robert P. P. and Johnston, Lynette and Breidt, Fred}, year={2023}, month={Jun} }
 @article{lu_marchant_thompson_melgarejo_ignatova_damaj_trejo_paramo_reed_breidt_et al._2022, title={Bacteriophages Isolated From Turkeys Infecting Diverse Salmonella Serovars}, volume={13}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2022.933751}, abstractNote={Salmonella is one of the leading causes of foodborne illnesses worldwide. The rapid emergence of multidrug-resistant Salmonella strains has increased global concern for salmonellosis. Recent studies have shown that bacteriophages (phages) are novel and the most promising antibacterial agents for biocontrol in foods because phages specifically kill target bacteria without affecting other bacteria, do not alter organoleptic properties or nutritional quality of foods, and are safe and environmentally friendly. Due to the vast variation in Salmonella serotypes, large numbers of different and highly virulent Salmonella phages with broad host ranges are needed. This study isolated 14 Salmonella phages from turkey fecal and cecal samples. Six phages (Φ205, Φ206, Φ207, ΦEnt, ΦMont, and Φ13314) were selected for characterization. These phages were from all three families in the Caudovirales order. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that each phage had a unique structural protein profile. Each phage had a distinct host range. Φ207 and ΦEnt are both siphophages. They shared eight hosts, including seven different Salmonella serovars and one Shigella sonnei strain. These two phages showed different restriction banding patterns generated through EcoRI or HindIII digestion, but shared three bands from EcoRI digestion. ΦEnt displayed the broadest and very unusual host range infecting 11 Salmonella strains from nine serovars and three Shigella strains from two species, and thus was further characterized. The one-step growth curve revealed that ΦEnt had a short latent period (10 min) and relatively large burst size (100 PFU/infected cell). ΦEnt and its host showed better thermal stabilities in tryptic soy broth than in saline at 63 or 72°C. In the model food system (cucumber juice or beef broth), ΦEnt infection [regardless of the multiplicity of infections (MOIs) of 1, 10, and 100] resulted in more than 5-log10 reduction in Salmonella concentration within 4 or 5 h. Such high lytic activity combined with its remarkably broad and unusual host range and good thermal stability suggested that ΦEnt is a novel Salmonella phage with great potential to be used as an effective biocontrol agent against diverse Salmonella serovars in foods.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Lu, Zhongjing and Marchant, John and Thompson, Samantha and Melgarejo, Henry and Ignatova, Dzhuliya and Damaj, Rana and Trejo, Hedy and Paramo, Rodrigo and Reed, Ashley and Breidt, Fred and et al.}, year={2022}, month={Jul} }
 @article{breidt_skinner_2022, title={Buffer Models for pH and Acid Changes Occurring in Cucumber Juice Fermented with Lactiplantibacillus pentosus and Leuconostoc mesenteroides}, volume={85}, ISSN={["1944-9097"]}, DOI={10.4315/JFP-22-068}, abstractNote={The pH changes that occur during the fermentation of vegetables by lactic acid bacteria depend on the production of weak acids but also the buffering of the fermentation medium. Undefined buffering components of fermentation media make estimates of pH from acid production difficult. The objective of this research was to develop buffer models for a model cucumber fermentation brine system linking pH changes to acid concentrations. A novel titration method was used to measure buffer capacity in cucumber juice media made from three different grades of pickling cucumbers based on diameter. Fermentation of juice made with different size cucumbers resulted in differences in fermentation biochemistry. The results of modeling showed that the pH of the media at 24 and 48 h of fermentation by heterolactic Leuconostoc mesenteroides and homolactic Lactiplantibacillus pentosus could be predicted from acid concentrations using the measured buffer capacity of the corresponding unfermented medium. The differences for all observed and predicted pH values of the fermentation samples, based on measured acid concentrations, had a root mean square error of 0.064 pH units. The buffer models included a quantitative measure of influence on pH due to the malolactic reaction by the lactic acid bacteria. These models may have application for assessing the influence of a variety of buffering reactions by lactic acid bacteria on pH and fermentation ecology, by linking pH to fermentation acid concentrations.}, number={9}, journal={JOURNAL OF FOOD PROTECTION}, author={Breidt, Fred and Skinner, Caitlin}, year={2022}, month={Sep}, pages={1273–1281} }
 @article{lafountain_johanningsmeier_breidt_stoforos_price_2022, title={Effects of a brief blanching process on quality, safety, and shelf life of refrigerated cucumber pickles}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.16112}, abstractNote={Refrigerated pickles are characterized by crisp, crunchy texture, opaque flesh, and fresh flavor. Typically produced without a thermal process, microbial safety relies on preventive controls, brine composition, and sufficient hold time prior to consumption. We hypothesized that brief blanching of whole cucumbers prior to pickling could provide an additional hurdle for pathogenic microbes without negatively impacting finished product quality. Blanch treatments (15, 90, or 180 s) in 80°C water were conducted in duplicate on two lots of cucumbers prior to cutting into spears, acidifying, and storing at 4°C. Enumeration of total aerobes, lactic acid bacteria, and glucose-fermenting coliforms was conducted for fresh and blanched cucumber. Texture, color, cured appearance development, and volatile compound profiles were analyzed for fresh and blanched cucumber and corresponding pickle products during refrigerated storage. The 90 s blanch consistently achieved a minimum 2-log reduction in cucumber microbiota and a predicted 5-log reduction of Escherichia coli O157:H7 up to 1.1 mm into the cucumber fruit. Blanching had no impact on tissue firmness during refrigerated storage for 1 year (p > 0.098). There were no differences in flavor-active lipid oxidation products (E,Z)-2,6-nonadienal and (E)-2-nonenal, and consumers (n = 110) were unable to differentiate between control and 90 s blanched cucumber pickles stored for 62 days. Exocarp color and mesocarp opacity were preserved by the blanching treatment, potentially extending product shelf life. This method offers processors an option for reducing the risk of microbial contamination while maintaining the quality attributes associated with refrigerated cucumber pickles. PRACTICAL APPLICATION: Refrigerated pickles do not undergo thermal processing, which can leave them vulnerable to microbial contamination. This study illustrates that adding a brief blanching step in refrigerated pickle processing can reduce indigenous microbiota without negatively impacting quality attributes. This blanching process could assist pickled vegetable manufacturers in providing additional safeguards for consumers while maintaining a high-quality product.}, journal={JOURNAL OF FOOD SCIENCE}, author={LaFountain, Lisa J. and Johanningsmeier, Suzanne D. and Breidt, Frederick, Jr. and Stoforos, George N. and Price, Robert E.}, year={2022}, month={Mar} }
 @article{lu_perez-diaz_hayes_breidt_2020, title={Bacteriophages Infecting Gram-Negative Bacteria in a Commercial Cucumber Fermentation}, volume={11}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2020.01306}, abstractNote={Cucumber fermentations are one of the most important vegetable fermentations in the United States. The fermentation is usually driven by lactic acid bacteria (LAB) indigenous to fresh cucumbers. But LAB are greatly outnumbered by many Gram-negative bacteria on fresh cucumbers, which may influence the growth of LAB and the incidence of bloater defect (hollow cavities formed inside fermented cucumbers) leading to serious economic loss to the pickle industry. Rapid elimination of Gram-negative bacteria is crucial to the dominance of LAB and the reduction of bloater defect in the fermentation. Various factors can affect the viability of Gram-negative bacteria in cucumber fermentation. Bacteriophages (phages) may be one of such factors. This study explored the abundance, diversity, and functional role of phages infecting Gram-negative bacteria in a commercial cucumber fermentation. Cover brine samples were taken from a commercial fermentation tank over a 30-day period. On day 1 and day 3 of the fermentation, 39 Gram-negative bacteria and 26 independent phages were isolated. Nearly 67% of Gram-negative bacterial isolates were susceptible to phage infection. Phage hosts include Enterobacter, Citrobacter, Escherichia, Pantoea, Serratia, Leclercia, Providencia, and Pseudomonas species. About 88% of the isolated phages infected the members in the family Enterobacteriaceae and 58% of phages infected Enterobacter species. Eight phages with unique host ranges were characterized. These phages belong to the Myoviridae, Siphoviridae, or Podoviridae family and showed distinct protein profiles and DNA fingerprints. The infectivity of a phage against Enterobacter cancerogenus was evaluated in cucumber juice as a model system. The phage infection at the multiplicity of infection 1 or 100 resulted in a 5-log reduction in cell concentration within 3 h and rapidly eliminated its host. This study revealed the abundance and variety of phages infecting Gram-negative bacteria, particularly Enterobacteriaceae, in the commercial cucumber fermentation, suggesting that phages may play an important role in the elimination of Gram-negative bacteria, thereby facilitating the dominance of LAB and minimizing bloater defect. To our knowledge, this is the first report on the ecology of phages infecting Gram-negative bacteria in commercial cucumber fermentations.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Lu, Zhongjing and Perez-Diaz, Ilenys M. and Hayes, Janet S. and Breidt, Fred}, year={2020}, month={Jun} }
 @article{jones_price_breidt_2020, title={Escherichia coli O157:H7 Stationary-Phase Acid Resistance and Assessment of Survival in a Model Vegetable Fermentation System}, volume={83}, ISSN={["1944-9097"]}, DOI={10.4315/JFP-19-463}, abstractNote={Escherichia coli O157:H7 (STEC) acid resistance may aid the pathogenâs ability to cross the human gastric barrier and makes it an organism of concern in acidic foods. Our objective was to determine how STEC acid resistance may correlate with survival during vegetable fermentations. Seven E. coli O157:H7 strains were screened to assess acid resistance in simulated stomach-acid at pH 2. The strains were separated into two groups that differed in acid resistance (p < 0.05), with three being acid sensitive and four acid resistant. The growth rates of these strains were measured in a Luria broth at pH values from 4.2 to 6.8. Two strains having similar growth kinetics, B201 (acid sensitive) and B241 (acid resistant), were selected for further analysis. B201 was found to be missing (compared to B241) two glutamic acid decarboxylase regulatory genes required for acid resistance, gadE and gadX. These strains were challenged in lactic acid (100 mM) solutions including cucumber juice (CJ) media at pH 3.3. As expected, B201 was more acid sensitive than B241, and a filtered fermented CJ was more inhibitory than similarly acidified CJ. In competitive growth studies with Lactobacillus plantarum LA445 in CJ, B201 or B241 grew from approximately 104 CFU/mL to 108 CFU/mL within 24 hours but the STEC strains were below the limit of detection by 48 hours. In all fermentations L. plantarum reached 108 CFU/mL by 48 hours. However, in three out of four independent fermentation experiments, strain B201 survived longer than B241. This was possibly due to buffering in B241-LA445 fermentation brines which had increased lactic acid for a given pH compared to B201-LA445. These data indicate that stationary phase acid resistance may not accurately predict STEC survival during vegetable fermentations.}, number={5}, journal={JOURNAL OF FOOD PROTECTION}, author={Jones, Clara M. and Price, Robert E. and Breidt, Fred}, year={2020}, month={May}, pages={745–753} }
 @article{price_longtin_conley-payton_osborne_johanningsmeier_bitzer_breidt_2020, title={Modeling buffer capacity and pH in acid and acidified foods}, volume={85}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.15091}, abstractNote={Standard ionic equilibria equations may be used for calculating pH of weak acid and base solutions. These calculations are difficult or impossible to solve analytically for foods that include many unknown buffering components, making pH prediction in these systems impractical. We combined buffer capacity (BC) models with a pH prediction algorithm to allow pH prediction in complex food matrices from BC data. Numerical models were developed using Matlab software to estimate the pH and buffering components for mixtures of weak acid and base solutions. The pH model was validated with laboratory solutions of acetic or citric acids with ammonia, in combinations with varying salts using Latin hypercube designs. Linear regressions of observed versus predicted pH values based on the concentration and pK values of the solution components resulted in estimated slopes between 0.96 and 1.01 with and without added salts. BC models were generated from titration curves for 0.6 M acetic acid or 12.4 mM citric acid resulting in acid concentration and pK estimates. Predicted pH values from these estimates were within 0.11 pH units of the measured pH. Acetic acid concentration measurements based on the model were within 6% accuracy compared to high-performance liquid chromatography measurements for concentrations less than 400 mM, although they were underestimated above that. The models may have application for use in determining the BC of food ingredients with unknown buffering components. Predicting pH changes for food ingredients using these models may be useful for regulatory purposes with acid or acidified foods and for product development. PRACTICAL APPLICATION: Buffer capacity models may benefit regulatory agencies and manufacturers of acid and acidified foods to determine pH stability (below pH 4.6) and how low-acid food ingredients may affect the safety of these foods. Predicting pH for solutions with known or unknown buffering components was based on titration data and models that use only monoprotic weak acids and bases. These models may be useful for product development and food safety by estimating pH and buffering capacity.}, number={4}, journal={JOURNAL OF FOOD SCIENCE}, author={Price, Robert E. and Longtin, Madyson and Conley-Payton, Summer and Osborne, Jason A. and Johanningsmeier, Suzanne D. and Bitzer, Donald and Breidt, Fred}, year={2020}, month={Apr}, pages={918–925} }
 @article{longtin_price_mishra_breidt_2020, title={Modeling the buffer capacity of ingredients in salad dressing products}, volume={85}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.15018}, abstractNote={The pH of most acid food products depends on undefined and complex buffering of ingredients but is critically important for regulatory purposes and food safety. Our objective was to define the buffer capacity (BC) of ingredients in salad dressing products. Ingredients of salad dressings were titrated individually and in combination using concentrations typical of dressing products. Titration curves from pH 2 to 12 were generated with sodium hydroxide and hydrochloric acid, which were then used to generate BC curves. A matrix of concentration and pK values for a series of monoprotic buffers approximated the pH of each ingredient. Some buffer series required anion or cation corrections for accurate pH prediction, possibly due to the presence of salts of acid or bases. Most buffers had BC values less than 10-fold the BC of acetic acid (0.25 β) typically in dressing formulations and had little influence on the final product pH of the dressings tested. Unexpectedly, we found that sugars in dressing formulations, including sucrose or corn syrup, exhibited buffering at pH values greater than 11 (0.035 β and 0.059 β, respectively), which was likely due to weakly acidic hydroxyl groups on the sugar molecules. However, the concentration and pK for buffers above pH 11 or below pH 2 were difficult to quantify due to the BC of water. The BC data may help to quantify the effects of salad dressing ingredients on the final product pH and benefit regulatory agencies and manufacturers in assessing product pH and safety. PRACTICAL APPLICATION: Buffer capacity data for salad dressing ingredients may help determine the influence ingredient addition will have on the final pH of a salad dressing product. The addition of low acid ingredients with little or no buffering may not significantly alter pH. The modeling method may be useful for regulatory purposes to estimate the effects of low acid ingredients on pH changes for food safety and may also be useful for product development of acid and acidified foods.}, number={4}, journal={JOURNAL OF FOOD SCIENCE}, author={Longtin, Madyson and Price, Robert E. and Mishra, Ritu and Breidt, Fred}, year={2020}, month={Apr}, pages={910–917} }
 @article{mcmurtrie_johanningsmeier_breidt_price_2019, title={Effect of Brine Acidification on Fermentation Microbiota, Chemistry, and Texture Quality of Cucumbers Fermented in Calcium or Sodium Chloride Brines}, volume={84}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.14600}, abstractNote={Commercial fermentation for bulk preservation of cucumbers relies on natural microbiota and approximately 1 M sodium chloride (NaCl) brines, resulting in large volumes of high-salt wastewater. An alternative process utilizing 0.1 M calcium chloride (CaCl2 ) as the only salt was developed to eliminate NaCl from fermentation brines for reduced environmental impact. This study determined the effect of brine acidification on the fermentation microbiota and texture quality of cucumbers fermented in CaCl2 brines. Cucumber fermentations were conducted in sealed glass jars for six independent lots of cucumbers in a randomized complete block design with a full-factorial treatment structure for brine acidification (acetic acid, hydrochloric acid, or nonacidified) and brining salt (1 M NaCl or 0.1 M CaCl2 ). Enterobacteriaceae spp. survived longer and were >1 log colony forming units/mL higher in fermenting cucumbers than in brines. Addition of 25 mM acetic acid to fermentation brines (but not the addition of hydrochloric acid at the same pH) reduced Enterobacteriaceae spp. in brines and cucumbers (P < 0.002) during the initiation of fermentation for both brining salts. However, acidification had no effect on texture quality of fermented cucumbers (P = 0.8235). Despite differences in early fermentation microbiota, fermentation of cucumbers in calcium chloride brines under controlled conditions, with or without acidification, resulted in high retention of tissue firmness. These results differ from fermentations in a commercial setting initiated in brines of neutral pH, indicating that production variables, such as air exposure, interact with brining in CaCl2 to negatively affect the texture quality of fermented cucumbers. PRACTICAL APPLICATION: This study examined the effects of initial brine acidification on the course of lactic acid fermentation and resulting texture quality of cucumbers fermented in calcium or sodium salt brines. Fermentation brines containing acetic acid (the acid in vinegar) reduced the pH of the cucumber and the soil-associated Enterobacteriaceae spp. most rapidly, and favored the conversion of sugars to lactic acid. Interestingly, the texture quality was not affected by brine acidification, and all cucumbers fermented in calcium brines in the absence of air retained their firmness during fermentation and bulk storage.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={McMurtrie, Erin K. and Johanningsmeier, Suzanne D. and Breidt, Fred, Jr. and Price, Robert E.}, year={2019}, month={May}, pages={1129–1137} }
 @article{dupree_price_burgess_andress_breidt_2019, title={Effects of Sodium Chloride or Calcium Chloride Concentration on the Growth and Survival of Escherichia coli O157:H7 in Model Vegetable Fermentations}, volume={82}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X.JFP-18-468}, abstractNote={HIGHLIGHTS
NaCl and CaCl2 concentrations affected LAB and STEC strains differently. Growth rates at 6% NaCl were reduced for STEC more than LAB in vegetable broth. Extent of growth was reduced for STEC versus LAB for most vegetable fermentations. Death rates were minimally affected by salt type or concentration with lactic acid. Correlations between salt and STEC die-off were inconsistent for fermentation.}, number={4}, journal={JOURNAL OF FOOD PROTECTION}, author={Dupree, Dorothy E. and Price, Robert E. and Burgess, Breanne A. and Andress, Elizabeth L. and Breidt, Frederick}, year={2019}, month={Apr}, pages={570–578} }
 @article{ding_johanningsmeier_price_reynolds_truong_payton_breidt_2018, title={Evaluation of nitrate and nitrite contents in pickled fruit and vegetable products}, volume={90}, ISSN={["1873-7129"]}, DOI={10.1016/j.foodcont.2018.03.005}, abstractNote={Our objective was to investigate nitrate and nitrite contents of acidified and fermented fruits and vegetables. l-ascorbic acid and total phenols were also examined based on the hypothesis that the presence of these antioxidant compounds may influence N-nitrosation reactions upon human consumption. The fermented and acidified vegetable products included 131 samples from multiple lots of 46 different commercially available products. Nitrite was detected in low concentrations (<1.5 mg/100 g) in four acidified (pickled green beans, red cabbage, pickled beets, and pickled mushrooms) and two fermented products (Greek olives and kimchi). Nitrate concentrations ranged from a mean value of 122 mg/100 g for kimchi to undetectable levels in acidified Brussels sprouts. Measures of antioxidant compounds showed that artichoke hearts had the highest total polyphenols (225 mg/100 g), and olive products had between 84 ± 5 mg/100 g (Spanish table olives) and 170 ± 8 mg/100 g (Greek olives). An acidified red pepper product had the highest l-ascorbic acid content of 32 ± 10 mg/100 g, with a low nitrate level of 0.1 ± 0.09 mg/100 g. These results provide new information for evaluating nitrate and nitrite contents in pickled fruit and vegetable products with regard to potential human dietary health consequences.}, journal={FOOD CONTROL}, author={Ding, Zhansheng and Johanningsmeier, Suzanne D. and Price, Robert and Reynolds, Rong and Truong, Van-Den and Payton, Summer Conley and Breidt, Fred}, year={2018}, month={Aug}, pages={304–311} }
 @article{kay_breidt_fratamico_baranzoni_kim_grunden_oh_2017, title={Escherichia coli O157:H7 Acid Sensitivity Correlates with Flocculation Phenotype during Nutrient Limitation}, volume={8}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2017.01404}, abstractNote={Shiga toxin producing Escherichia coli (STEC) strains vary in acid resistance; however, little is known about the underlying mechanisms that result in strain specific differences. Among 25 STEC O157:H7 strains tested, 7 strains flocculated when grown statically for 18 h in minimal salts medium at 37°C, while 18 strains did not. Interestingly, the flocculation phenotype (cells came out of suspension) was found to correlate with degree of acid sensitivity in an assay with 400 mM acetic acid solution at pH 3.3 targeting acidified foods. Strains exhibiting flocculation were more acid sensitive and were designated FAS, for flocculation acid sensitive, while the acid resistant strain designated PAR for planktonic acid resistant. Flocculation was not observed for any strains during growth in complex medium (Luria Bertani broth). STEC strains B201 and B241 were chosen as representative FAS (2.4 log reduction) and PAR (0.15 log reduction) strains, respectively, due to differences in acid resistance and flocculation phenotype. Results from electron microscopy showed evidence of fimbriae production in B201, whereas fimbriae were not observed in B241.Curli fimbriae production was identified through plating on Congo red differential medium, and all FAS strains showed curli fimbriae production. Surprisingly, 5 PAR strains also had evidence of curli production. Transcriptomic and targeted gene expression data for B201 and B241indicated that csg and hde (curli and acid induced chaperone genes, respectively) expression positively correlated with the phenotypic differences observed for these strains. These data suggest that FAS strains grown in minimal medium express curli, resulting in a flocculation phenotype. This may be regulated by GcvB, which positively regulates curli fimbriae production and represses acid chaperone proteins. RpoS and other regulatory mechanisms may impact curli fimbriae production, as well. These findings may help elucidate mechanisms underlying differences among STEC strains in relating acid resistance and biofilm formation.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Kay, Kathryn L. and Breidt, Frederick and Fratamico, Pina M. and Baranzoni, Gian M. and Kim, Gwang-Hee and Grunden, Amy M. and Oh, Deog-Hwan}, year={2017}, month={Jul} }
 @article{fan_breidt_price_perez-diaz_2017, title={Survival and Growth of Probiotic Lactic Acid Bacteria in Refrigerated Pickle Products}, volume={82}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.13579}, abstractNote={We examined 10 lactic acid bacteria that have been previously characterized for commercial use as probiotic cultures, mostly for dairy products, including 1 Pediococcus and 9 Lactobacilli. Our objectives were to develop a rapid procedure for determining the long-term survivability of these cultures in acidified vegetable products and to identify suitable cultures for probiotic brined vegetable products. We therefore developed assays to measure acid resistance of these cultures to lactic and acetic acids, which are present in pickled vegetable products. We used relatively high acid concentrations (compared to commercial products) of 360 mM lactic acid and 420 mM acetic acid to determine acid resistance with a 1 h treatment. Growth rates were measured in a cucumber juice medium at pH 5.3, 4.2, and 3.8, at 30 °C and 0% to 2% NaCl. Significant differences in acid resistance and growth rates were found among the 10 cultures. In general, the acid resistant strains had slower growth rates than the acid sensitive strains. Based on the acid resistance data, selected cultures were tested for long-term survival in a simulated acidified refrigerated cucumber product. We found that one of the most acid resistant strains (Lactobacillus casei) could survive for up to 63 d at 4 °C without significant loss of viability at 108 CFU/mL. These data may aid in the development of commercial probiotic refrigerated pickle products.}, number={1}, journal={JOURNAL OF FOOD SCIENCE}, author={Fan, Sicun and Breidt, Fred and Price, Robert and Perez-Diaz, Ilenys}, year={2017}, month={Jan}, pages={167–173} }
 @article{kim_fratamico_breidt_oh_2016, title={Survival and expression of acid resistance genes in Shiga toxin-producing Escherichia coli acid adapted in pineapple juice and exposed to synthetic gastric fluid}, volume={121}, ISSN={["1365-2672"]}, DOI={10.1111/jam.13223}, abstractNote={The aim of this research was to determine the ability of non‐O157 Shiga toxin‐producing Escherichia coli (STEC) serogroups to survive with exposure to synthetic gastric fluid (SGF) after adaptation to pineapple juice (PJ) at room and refrigerated temperatures compared to E. coli O157:H7 and to examine the relative transcriptional expression of acid resistance (AR) genes, rpoS, gadA and adiA.}, number={5}, journal={JOURNAL OF APPLIED MICROBIOLOGY}, author={Kim, G-H. and Fratamico, P. and Breidt, F. and Oh, D-H.}, year={2016}, month={Nov}, pages={1416–1426} }
 @article{kim_breidt_fratamico_oh_2015, title={Acid Resistance and Molecular Characterization of Escherichia coli O157:H7 and Different Non-O157 Shiga Toxin-Producing E. coli Serogroups}, volume={80}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.12996}, abstractNote={The objective of this study was to compare the acid resistance (AR) of non-O157 Shiga toxin-producing Escherichia coli (STEC) strains belonging to serogroups O26, O45, O103, O104, O111, O121, and O145 with O157:H7 STEC isolated from various sources in 400 mM acetic acid solutions (AAS) at pH 3.2 and 30 °C for 25 min with or without glutamic acid. Furthermore, the molecular subgrouping of the STEC strains was analyzed with the repetitive sequence-based PCR (rep-PCR) method using a DiversiLab(TM) system. Results for a total of 52 strains ranged from 0.31 to 5.45 log reduction CFU/mL in the absence of glutamic acid and 0.02 to 0.33 CFU/mL in the presence of glutamic acid except for B447 (O26:H11), B452 (O45:H2), and B466 (O104:H4) strains. Strains belonging to serogroups O111, O121, and O103 showed higher AR than serotype O157:H7 strains in the absence of glutamic acid. All STEC O157:H7 strains exhibited a comparable DNA pattern with more than 95% similarity in the rep-PCR results, as did the strains belonging to serogroups O111 and O121. Surprisingly, the DNA pattern of B458 (O103:H2) was similar to that of O157:H7 strains with 82% similarity, and strain B458 strain showed the highest AR to AAS among the O103 strains with 0.44 log reduction CFU/mL without glutamic acid. In conclusion, STEC serotypes isolated from different sources exhibited diverse AR and genetic subtyping patterns. Results indicated that some non-O157 STEC strains may have higher AR than STEC O157:H7 strains under specific acidic conditions, and the addition of glutamic acid provided enhanced protection against exposure to AAS.}, number={10}, journal={JOURNAL OF FOOD SCIENCE}, author={Kim, Gwang-Hee and Breidt, Frederick and Fratamico, Pina and Oh, Deog-Hwan}, year={2015}, month={Oct}, pages={M2257–M2264} }
 @article{yang_meng_breidt_dean_arritt_2015, title={Effects of Acetic Acid and Arginine on pH Elevation and Growth of Bacillus licheniformis in an Acidified Cucumber Juice Medium}, volume={78}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x.jfp-14-478}, abstractNote={Bacillus licheniformis has been shown to cause pH elevation in tomato products having an initial pH below 4.6 and metabiotic effects that can lead to the growth of pathogenic bacteria. Because of this, the organism poses a potential risk to acidified vegetable products; however, little is known about the growth and metabolism of this organism in these products. To clarify the mechanisms of pH change and growth of B. licheniformis in vegetable broth under acidic conditions, a cucumber juice medium representative of a noninhibitory vegetable broth was used to monitor changes in pH, cell growth, and catabolism of sugars and amino acids. For initial pH values between pH 4.1 to 6.0, pH changes resulted from both fermentation of sugar (lowering pH) and ammonia production (raising pH). An initial pH elevation occurred, with starting pH values of pH 4.1 to 4.9 under both aerobic and anaerobic conditions, and was apparently mediated by the arginine deiminase reaction of B. licheniformis. This initial pH elevation was prevented if 5 mM or greater acetic acid was present in the brine at the same pH. In laboratory media, under favorable conditions for growth, data indicated that growth of the organism was inhibited at pH 4.6 with protonated acetic acid concentrations of 10 to 20 mM, corresponding to 25 to 50 mM total acetic acid; however, growth inhibition required greater than 300 mM citric acid (10-fold excess of the amount in processed tomato products) products under similar conditions. The data indicate that growth and pH increase by B. licheniformis may be inhibited by the acetic acid present in most commercial acidified vegetable products but not by the citric acid in many tomato products.}, number={4}, journal={JOURNAL OF FOOD PROTECTION}, author={Yang, Zhenquan and Meng, Xia and Breidt, Frederick, Jr. and Dean, Lisa L. and Arritt, Fletcher M.}, year={2015}, month={Apr}, pages={728–737} }
 @article{lu_breidt_2015, title={Escherichia coli O157:H7 bacteriophage Phi 241 isolated from an industrial cucumber fermentation at high acidity and salinity}, volume={6}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2015.00067}, abstractNote={A novel phage, Φ241, specific for Escherichia coli O157:H7 was isolated from an industrial cucumber fermentation where both acidity (pH ≤ 3.7) and salinity (≥5% NaCl) were high. The phage belongs to the Myoviridae family. Its latent period was 15 min and average burst size was 53 phage particles per infected cell. The phage was able to lyse 48 E. coli O157:H7 strains, but none of the 18 non-O157 strains (including E. coli O104:H7) or the 2 O antigen-negative mutants of O157:H7 strain, 43895Δper (also lacking H7 antigen) and F12 (still expressing H7 antigen). However, the phage was able to lyse a per-complemented strain (43895ΔperComp) which expresses O157 antigen. These results indicated that phage Φ241 is specific for O157 antigen, and E. coli strains lacking O157 antigen were resistant to the phage infection, regardless of the presence or absence of H7 antigen. SDS-PAGE profile revealed at least 13 structural proteins of the phage. The phage DNA was resistant to many commonly used restriction endonucleases, suggesting the presence of modified nucleotides in the phage genome. At the multiplicity of infection of 10, 3, or 0.3, the phage caused a rapid cell lysis within 1 or 2 h, resulting in 3.5- or 4.5-log-unit reduction in cell concentration. The high lytic activity, specificity and tolerance to low pH and high salinity make phage Φ241 a potentially ideal biocontrol agent of E. coli O157:H7 in various foods. To our knowledge, this is the first report on E. coli O157:H7 phage isolated from high acidity and salinity environment.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Lu, Zhongjing and Breidt, Fred}, year={2015}, month={Feb} }
 @article{breidt_medina_wafa_perez-diaz_franco_huang_johanningsmeier_kim_2013, title={Characterization of Cucumber Fermentation Spoilage Bacteria by Enrichment Culture and 16S rDNA Cloning}, volume={78}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.12057}, abstractNote={UNLABELLED
Commercial cucumber fermentations are typically carried out in 40000 L fermentation tanks. A secondary fermentation can occur after sugars are consumed that results in the formation of acetic, propionic, and butyric acids, concomitantly with the loss of lactic acid and an increase in pH. Spoilage fermentations can result in significant economic loss for industrial producers. The microbiota that result in spoilage remain incompletely defined. Previous studies have implicated yeasts, lactic acid bacteria, enterobacteriaceae, and Clostridia as having a role in spoilage fermentations. We report that Propionibacterium and Pectinatus isolates from cucumber fermentation spoilage converted lactic acid to propionic acid, increasing pH. The analysis of 16S rDNA cloning libraries confirmed and expanded the knowledge gained from previous studies using classical microbiological methods. Our data show that Gram-negative anaerobic bacteria supersede Gram-positive Fermincutes species after the pH rises from around 3.2 to pH 5, and propionic and butyric acids are produced. Characterization of the spoilage microbiota is an important first step in efforts to prevent cucumber fermentation spoilage.


PRACTICAL APPLICATION
An understanding of the microorganisms that cause commercial cucumber fermentation spoilage may aid in developing methods to prevent the spoilage from occurring.}, number={3}, journal={JOURNAL OF FOOD SCIENCE}, author={Breidt, Fred and Medina, Eduardo and Wafa, Doria and Perez-Diaz, Ilenys and Franco, Wendy and Huang, Hsin-Yu and Johanningsmeier, Suzanne D. and Kim, Jae Ho}, year={2013}, month={Mar}, pages={M470–M476} }
 @article{breidt_kay_cook_osborne_ingham_arritt_2013, title={Determination of 5-Log Reduction Times for Escherichia coli O157:H7, Salmonella enterica, or Listeria monocytogenes in Acidified Foods with pH 3.5 or 3.8}, volume={76}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x.jfp-12-528}, abstractNote={A critical factor in ensuring the safety of acidified foods is the establishment of a thermal process that assures the destruction of acid-resistant vegetative pathogenic and spoilage bacteria. For acidified foods such as dressings and mayonnaises with pH values of 3.5 or higher, the high water phase acidity (acetic acid of 1.5 to 2.5% or higher) can contribute to lethality, but there is a lack of data showing how the use of common ingredients such as acetic acid and preservatives, alone or in combination, can result in a 5-log reduction for strains of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes in the absence of a postpackaging pasteurization step. In this study, we determined the times needed at 10° C to achieve a 5-log reduction of E. coli O157:H7, S. enterica, and L. monocytogenes in pickling brines with a variety of acetic and benzoic acid combinations at pH 3.5 and 3.8. Evaluation of 15 different acid-pH combinations confirmed that strains of E. coli O157:H7 were significantly more acid resistant than strains of S. enterica and L. monocytogenes. Among the acid conditions tested, holding times of 4 days or less could achieve a 5-log reduction for vegetative pathogens at pH 3.5 with 2.5% acetic acid or at pH 3.8 with 2.5% acetic acid containing 0.1% benzoic acid. These data indicate the efficacy of benzoic acid for reducing the time necessary to achieve a 5-log reduction in target pathogens and may be useful for supporting process filings and the determination of critical controls for the manufacture of acidified foods.}, number={7}, journal={JOURNAL OF FOOD PROTECTION}, author={Breidt, F., Jr. and Kay, K. and Cook, J. and Osborne, J. and Ingham, B. and Arritt, F.}, year={2013}, month={Jul}, pages={1245–1249} }
 @article{lu_breidt_perez-diaz_2013, title={Development of an Effective Treatment for A 5-Log Reduction of Escherichia coli in Refrigerated Pickle Products}, volume={78}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2012.02968.x}, abstractNote={UNLABELLED
Refrigerated cucumber pickle products cannot be heat processed due to the loss of characteristic sensory attributes. Typically brined refrigerated pickles contain less than 100 mM acetic acid with pH values of 3.7 to 4.0. Refrigeration (4 to 10 °C) helps to inhibit the growth of spoilage bacteria and maintain flavor, texture, and appearance of the pickles. Previous research has shown that pathogenic Escherichia coli strains are unusually acid resistant and survive better in refrigerated acid solutions than at higher temperatures. We found that E. coli O157:H7 can survive for 1 mo or longer at 4 °C in brines typical of commercial refrigerated pickles. Our objective was to develop methods to assure a 5-log reduction of pathogenic E. coli in these types of products, while maintaining the sensory characteristics. A novel brine formulation was developed, based on current commercial refrigerated pickle brines, which contained 25 mM fumaric acid, 5 mM benzoic acid, 70 mM acetic acid, and 342 mM (2%) sodium chloride, with a pH of 3.8. Sensory data indicate that this formulation did not affect flavor or other sensory attributes of the product, compared to traditional formulations. We achieved a 5-log reduction of E. coli O157:H7 at 30 °C for 1.52 ± 0.15 d, at 20 °C for 3.12 ± 0.34 d, or at 10 °C for 8.83 ± 0.56 d. Growth of lactic acid bacteria was also inhibited. These results can be used by manufacturers to assure a 5-log reduction in cell numbers of E. coli O157:H7 and Salmonella without a heat process during the manufacture of refrigerated pickle products.


PRACTICAL APPLICATION
While refrigerated acidified vegetable products are exempt from the acidified foods regulations, we have shown that the vegetative microbial pathogens E. coli O157:H7 can survive for up to 1 mo in these products, given current commercial production practices. To improve the safety of refrigerated pickle products, a brine formulation with reduced acetic acid, but containing fumaric acid, was developed to assure a 5-log reduction in cell numbers of E. coli O157:H7 without a heat process. The formulation can be used to assure the safety of refrigerated pickled vegetables without altering sensory characteristics.}, number={2}, journal={JOURNAL OF FOOD SCIENCE}, author={Lu, Huiying J. and Breidt, Frederick, Jr. and Perez-Diaz, Ilenys}, year={2013}, month={Feb}, pages={M264–M269} }
 @article{nawalakhe_shi_vitchuli_noar_caldwell_breidt_bourham_zhang_mccord_2013, title={Novel atmospheric plasma enhanced chitosan nanofiber/gauze composite wound dressings}, volume={129}, ISSN={0021-8995}, url={http://dx.doi.org/10.1002/app.38804}, DOI={10.1002/app.38804}, abstractNote={Electrospun chitosan nanofibers were deposited onto atmospheric plasma treated cotton gauze to create a novel compos- ite bandage with higher adhesion, better handling properties, enhanced bioactivity, and moisture management. Plasma treatment of the gauze substrate was performed to improve the durability of the nanofiber/gauze interface. The chitosan nanofibers were electro- spun at 3-7% concentration in trifluoroacetic acid. The composite bandages were analyzed using peel, gelbo flex, antimicrobial assay, moisture vapor transmission rate, X-ray photoelectron spectroscopy (XPS), absorbency, and air permeability tests. The peel test showed that plasma treatment of the substrate increased the adhesion between nanofiber layers and gauze substrate by up to four times. Atmospheric plasma pretreatment of the gauze fabric prior to electrospinning significantly reduced degradation of the nano- fiber layer due to repetitive flexing. The chitosan nanofiber layer contributes significantly to the antimicrobial properties of the band- age. Air permeability and moisture vapor transport were reduced due to the presence of a nanofiber layer upon the substrate. XPS of the plasma treated cotton substrate showed formation of active sites on the surface, decrease in carbon content, and increase in oxy- gen content as compared to the untreated gauze. Deposition of chitosan nanofibers also increased the absorbency of gauze substrate. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 129: 916-923, 2013}, number={2}, journal={Journal of Applied Polymer Science}, publisher={Wiley}, author={Nawalakhe, Rupesh and Shi, Quan and Vitchuli, Narendiran and Noar, Jesse and Caldwell, Jane M. and Breidt, Frederick and Bourham, Mohamed A. and Zhang, Xiangwu and McCord, Marian G.}, year={2013}, month={Feb}, pages={916–923} }
 @article{lu_breidt_perez-diaz_osborne_2011, title={Antimicrobial Effects of Weak Acids on the Survival of Escherichia coli O157:H7 under Anaerobic Conditions}, volume={74}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x.jfp-10-404}, abstractNote={Outbreaks of disease due to vegetative bacterial pathogens associated with acid foods (such as apple cider) have raised concerns about acidified vegetables and related products that have a similar pH (3.2 to 4.0). Escherichia coli O157:H7 and related strains of enterohemorrhagic E. coli (EHEC) have been identified as the most acid resistant vegetative pathogens in these products. Previous research has shown that the lack of dissolved oxygen in many hermetically sealed acid or acidified food products can enhance survival of EHEC compared with their survival under aerobic conditions. We compared the antimicrobial effects of several food acids (acetic, malic, lactic, fumaric, benzoic, and sorbic acids and sulfite) on a cocktail of EHEC strains under conditions representative of non-heat-processed acidified vegetables in hermetically sealed jars, holding the pH (3.2) and ionic strength (0.342) constant under anaerobic conditions. The overall antimicrobial effectiveness of weak acids used in this study was ranked, from most effective to least effective: sulfite > benzoic acid > sorbic acid > fumaric acid > L- and D-lactic acid > acetic acid > malic acid. These rankings were based on the estimated protonated concentrations required to achieve a 5-log reduction in EHEC after 24 h of incubation at 30°C. This study provides information that can be used to formulate safer acid and acidified food products and provides insights about the mode of action of weak acids against EHEC.}, number={6}, journal={JOURNAL OF FOOD PROTECTION}, author={Lu, Huiying J. and Breidt, Frederick, Jr. and Perez-Diaz, Ilenys M. and Osborne, Jason A.}, year={2011}, month={Jun}, pages={893–898} }
 @article{shi_vitchuli_nowak_caldwell_breidt_bourham_zhang_mccord_2011, title={Durable antibacterial Ag/polyacrylonitrile (Ag/PAN) hybrid nanofibers prepared by atmospheric plasma treatment and electrospinning}, volume={47}, ISSN={["1873-1945"]}, url={https://publons.com/publon/3117884/}, DOI={10.1016/j.eurpolymj.2011.04.002}, abstractNote={Durable antibacterial Ag/polyacrylonitrile (Ag/PAN) hybrid nanofibers were prepared by atmospheric plasma treatment and electrospinning. Atmospheric helium plasma treatment was first used to reduce the AgNO3 precursor in pre-electrospinning solutions into metallic silver nanoparticles, followed by electrospinning into continuous and smooth nanofibers with Ag nanoparticles embedded in the matrix. SEM, TEM, and EDX spectra were used to study the structure and surface elemental composition of the nanofibers. Silver nanoparticles, with diameters ranging between 3 and 6 nm, were found to be uniformly dispersed in the nanofiber matrix. The Ag/PAN nanofibers exhibited slow and long-lasting silver ion release, which provided robust antibacterial activity against both Gram-positive Bacillus cereus and Gram-negative Escherichia coli microorganisms.}, number={7}, journal={EUROPEAN POLYMER JOURNAL}, author={Shi, Quan and Vitchuli, Narendiran and Nowak, Joshua and Caldwell, Jane M. and Breidt, Frederick and Bourham, Mohamed and Zhang, Xiangwu and McCord, Marian}, year={2011}, month={Jul}, pages={1402–1409} }
 @article{hosein_breidt_smith_2011, title={Modeling the Effects of Sodium Chloride, Acetic Acid, and Intracellular pH on Survival of Escherichia coli O157:H7}, volume={77}, ISSN={["1098-5336"]}, DOI={10.1128/aem.02136-10}, abstractNote={ABSTRACT Microbiological safety has been a critical issue for acid and acidified foods since it became clear that acid-tolerant pathogens such as Escherichia coli O157:H7 can survive (even though they are unable to grow) in a pH range of 3 to 4, which is typical for these classes of food products. The primary antimicrobial compounds in these products are acetic acid and NaCl, which can alter the intracellular physiology of E. coli O157:H7, leading to cell death. For combinations of acetic acid and NaCl at pH 3.2 (a pH value typical for non-heat-processed acidified vegetables), survival curves were described by using a Weibull model. The data revealed a protective effect of NaCl concentration on cell survival for selected acetic acid concentrations. The intracellular pH of an E. coli O157:H7 strain exposed to acetic acid concentrations of up to 40 mM and NaCl concentrations between 2 and 4% was determined. A reduction in the intracellular pH was observed for increasing acetic acid concentrations with an external pH of 3.2. Comparing intracellular pH with Weibull model predictions showed that decreases in intracellular pH were significantly correlated with the corresponding times required to achieve a 5-log reduction in the number of bacteria.}, number={3}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Hosein, Althea M. and Breidt, Frederick, Jr. and Smith, Charles E.}, year={2011}, month={Feb}, pages={889–895} }
 @article{vitchuli_shi_nowak_kay_caldwell_breidt_bourham_mccord_zhang_2011, title={Multifunctional ZnO/Nylon 6 nanofiber mats by an electrospinning-electrospraying hybrid process for use in protective applications}, volume={12}, ISSN={["1468-6996"]}, url={https://publons.com/publon/3117882/}, DOI={10.1088/1468-6996/12/5/055004}, abstractNote={Abstract ZnO/Nylon 6 nanofiber mats were prepared by an electrospinning–electrospraying hybrid process in which ZnO nanoparticles were dispersed on the surface of Nylon 6 nanofibers without becoming completely embedded. The prepared ZnO/Nylon 6 nanofiber mats were evaluated for their abilities to kill bacteria or inhibit their growth and to catalytically detoxify chemicals. Results showed that these ZnO/Nylon 6 nanofiber mats had excellent antibacterial efficiency (99.99%) against both the Gram-negative Escherichia coli and Gram-positive Bacillus cereus bacteria. In addition, they exhibited good detoxifying efficiency (95%) against paraoxon, a simulant of highly toxic chemicals. ZnO/Nylon 6 nanofiber mats were also deposited onto nylon/cotton woven fabrics and the nanofiber mats did not significantly affect the moisture vapor transmission rates and air permeability values of the fabrics. Therefore, ZnO/Nylon 6 nanofiber mats prepared by the electrospinning–electrospraying hybrid process are promising material candidates for protective applications.}, number={5}, journal={SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS}, author={Vitchuli, Narendiran and Shi, Quan and Nowak, Joshua and Kay, Kathryn and Caldwell, Jane M. and Breidt, Frederick and Bourham, Mohamed and McCord, Marian and Zhang, Xiangwu}, year={2011}, month={Oct} }
 @article{shi_vitchuli_nowak_noar_caldwell_breidt_bourham_mccord_zhang_2011, title={One-step synthesis of silver nanoparticle-filled nylon 6 nanofibers and their antibacterial properties}, volume={21}, ISSN={["1364-5501"]}, url={https://publons.com/publon/274770/}, DOI={10.1039/c1jm11492a}, abstractNote={A novel and facile one-step approach to in situ synthesize silver nanoparticle-filled nylon 6 nanofibers by electrospinning is reported. The method does not need post-treatments and can be carried out at ambient conditions without using additional chemicals. It employs the electrospinning solvent as a reducing agent for in situ conversion of AgNO3 into silver nanoparticles during the solution preparation. The resultant silver nanoparticle-filled nylon 6 hybrid nanofibers show an excellent fibrous structure (fiber diameter at 50–150 nm), with narrow size 2–4 nm silver nanoparticles uniformly dispersed throughout the nylon 6 matrix. DSC analysis shows that the in situ incorporation of silver nanoparticles increased the Tg and crystallinity of the resultant nanofibers. These silver nanoparticle-filled nylon 6 nanofibers exhibit a steady and long-lasting silver ion release behavior, and robust antibacterial activity against both Gram-positive B. cereus and Gram-negative E. coli microorganisms.}, number={28}, journal={JOURNAL OF MATERIALS CHEMISTRY}, author={Shi, Quan and Vitchuli, Narendiran and Nowak, Joshua and Noar, Jesse and Caldwell, Jane M. and Breidt, Frederick and Bourham, Mohamed and McCord, Marian and Zhang, Xiangwu}, year={2011}, pages={10330–10335} }
 @article{breidt_caldwell_2011, title={Survival of Escherichia coli O157:H7 in cucumber fermentation brines}, volume={76}, DOI={10.1111/j.1750-3841.2011.02045.x}, abstractNote={UNLABELLED
Bacterial pathogens have been reported on fresh cucumbers and other vegetables used for commercial fermentation. The Food and Drug Administration currently has a 5-log reduction standard for E. coli O157:H7 and other vegetative pathogens in acidified pickle products. For fermented vegetables, which are acid foods, there is little data documenting the conditions needed to kill acid resistant pathogens. To address this knowledge gap, we obtained 10 different cucumber fermentation brines at different stages of fermentation from 5 domestic commercial plants. Cucumber brines were used to represent vegetable fermentations because cabbage and other vegetables may have inhibitory compounds that may affect survival. The 5-log reduction times for E. coli O157:H7 strains in the commercial brines were found to be positively correlated with brine pH, and ranged from 3 to 24 d for pH values of 3.2 to 4.6, respectively. In a laboratory cucumber juice medium that had been previously fermented with Lactobacillus plantarum or Leuconostoc mesenteroides (pH 3.9), a 5-log reduction was achieved within 1 to 16 d depending on pH, acid concentration, and temperature. During competitive growth at 30 °C in the presence of L. plantarum or L. mesenteroides in cucumber juice, E. coli O157:H7 cell numbers were reduced to below the level of detection within 2 to 3 d. These data may be used to aid manufacturers of fermented vegetable products determine safe production practices based on fermentation pH and temperature.


PRACTICAL APPLICATION
  Disease causing strains of the bacterium E. coli may be present on fresh vegetables. Our investigation determined the time needed to kill E. coli in cucumber fermentation brines and how E. coli strains are killed in competition with naturally present lactic acid bacteria. Our results showed how brine pH and other brine conditions affected the killing of E. coli strains. These data can be used by producers of fermented vegetable products to help assure consumer safety.}, number={3}, journal={Journal of Food Science}, author={Breidt, F. and Caldwell, J. M.}, year={2011}, pages={M198–203} }
 @article{lu_altermann_breidt_kozyavkin_2010, title={Sequence Analysis of Leuconostoc mesenteroides Bacteriophage Phi 1-A4 Isolated from an Industrial Vegetable Fermentation}, volume={76}, ISSN={["1098-5336"]}, DOI={10.1128/aem.02126-09}, abstractNote={ABSTRACT Vegetable fermentations rely on the proper succession of a variety of lactic acid bacteria (LAB). Leuconostoc mesenteroides initiates fermentation. As fermentation proceeds, L. mesenteroides dies off and other LAB complete the fermentation. Phages infecting L. mesenteroides may significantly influence the die-off of L. mesenteroides. However, no L. mesenteroides phages have been previously genetically characterized. Knowledge of more phage genome sequences may provide new insights into phage genomics, phage evolution, and phage-host interactions. We have determined the complete genome sequence of L. mesenteroides phage Φ1-A4, isolated from an industrial sauerkraut fermentation. The phage possesses a linear, double-stranded DNA genome consisting of 29,508 bp with a G+C content of 36%. Fifty open reading frames (ORFs) were predicted. Putative functions were assigned to 26 ORFs (52%), including 5 ORFs of structural proteins. The phage genome was modularly organized, containing DNA replication, DNA-packaging, head and tail morphogenesis, cell lysis, and DNA regulation/modification modules. In silico analyses showed that Φ1-A4 is a unique lytic phage with a large-scale genome inversion (∼30% of the genome). The genome inversion encompassed the lysis module, part of the structural protein module, and a cos site. The endolysin gene was flanked by two holin genes. The tail morphogenesis module was interspersed with cell lysis genes and other genes with unknown functions. The predicted amino acid sequences of the phage proteins showed little similarity to other phages, but functional analyses showed that Φ1-A4 clusters with several Lactococcus phages. To our knowledge, Φ1-A4 is the first genetically characterized L. mesenteroides phage.}, number={6}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Lu, Z. and Altermann, E. and Breidt, F. and Kozyavkin, S.}, year={2010}, month={Mar}, pages={1955–1966} }
 @article{pan_breidt_gorski_2010, title={Synergistic Effects of Sodium Chloride, Glucose, and Temperature on Biofilm Formation by Listeria monocytogenes Serotype 1/2a and 4b Strains}, volume={76}, ISSN={["1098-5336"]}, DOI={10.1128/aem.02185-09}, abstractNote={ABSTRACT Biofilm formation by Listeria monocytogenes is generally associated with its persistence in the food-processing environment. Serotype 1/2a strains make up more than 50% of the total isolates recovered from food and the environment, while serotype 4b strains are most often associated with major outbreaks of human listeriosis. Using a microplate assay with crystal violet staining, we examined biofilm formation by 18 strains of each serotype in tryptic soy broth with varying concentrations of glucose (from 0.25% to 10.0%, wt/vol), sodium chloride (from 0.5% to 7.0%, wt/vol) and ethanol (from 1% to 5.0%, vol/vol), and at different temperatures (22.5°C, 30°C, and 37°C). A synergistic effect on biofilm formation was observed for glucose, sodium chloride, and temperature. The serotype 1/2a strains generally formed higher-density biofilms than the 4b strains under most conditions tested. Interestingly, most serotype 4b strains had a higher growth rate than the 1/2a strains, suggesting that the growth rate may not be directly related to the capacity for biofilm formation. Crystal violet was found to stain both bacterial cells and biofilm matrix material. The enhancement in biofilm formation by environmental factors was apparently due to the production of extracellular polymeric substances instead of the accumulation of viable biofilm cells.}, number={5}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Pan, Youwen and Breidt, Frederick, Jr. and Gorski, Lisa}, year={2010}, month={Mar}, pages={1433–1441} }
 @article{pan_breidt_kathariou_2009, title={Competition of Listeria monocytogenes serotype 1/2a and 4b strains in mixed-culture biofilms}, volume={75}, DOI={10.1128/AEM.00816-09}, abstractNote={ABSTRACT The majority of Listeria monocytogenes isolates recovered from foods and the environment are strains of serogroup 1/2, especially serotypes 1/2a and 1/2b. However, serotype 4b strains cause the majority of human listeriosis outbreaks. Our investigation of L. monocytogenes biofilms used a simulated food-processing system that consisted of repeated cycles of growth, sanitation treatment, and starvation to determine the competitive fitness of strains of serotypes 1/2a and 4b in pure and mixed-culture biofilms. Selective enumeration of strains of a certain serotype in mixed-culture biofilms on stainless steel coupons was accomplished by using serotype-specific quantitative PCR and propidium monoazide treatment to prevent amplification of extracellular DNA or DNA from dead cells. The results showed that the serotype 1/2a strains tested were generally more efficient at forming biofilms and predominated in the mixed-culture biofilms. The growth and survival of strains of one serotype were not inhibited by strains of the other serotype in mixed-culture biofilms. However, we found that a cocktail of serotype 4b strains survived and grew significantly better in mixed-culture biofilms containing a specific strain of serotype 1/2a (strain SK1387), with final cell densities averaging 0.5 log10 CFU/cm2 higher than without the serotype 1/2a strain. The methodology used in this study contributed to our understanding of how environmental stresses and microbial competition influence the survival and growth of L. monocytogenes in pure and mixed-culture biofilms.}, number={18}, journal={Applied and Environmental Microbiology}, author={Pan, Y. W. and Breidt, F. and Kathariou, S.}, year={2009}, pages={5846–5852} }
 @article{oh_pan_berry_cooley_mandrell_breidt_2009, title={Escherichia coli O157:H7 Strains Isolated from Environmental Sources Differ Significantly in Acetic Acid Resistance Compared with Human Outbreak Strains}, volume={72}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-72.3.503}, abstractNote={A number of studies on the influence of acid on Escherichia coli O157:H7 have shown considerable strain differences, but limited information has been reported to compare the acid resistance based on the different sources of E. coli O157:H7 isolates. The purpose of this study was to determine the survival of E. coli O157:H7 strains isolated from five sources (foods, bovine carcasses, bovine feces, water, and human) in 400 mM acetic acid solutions under conditions that are typical of acidified foods. The isolates from bovine carcasses, feces, and water survived acetic acid treatment at pH 3.3 and 30 degrees C significantly (P < or = 0.05) better than did any food or human isolates. However, resistance to acetic acid significantly increased as temperature decreased to 15 degrees C for a given pH, with little (P > or = 0.05) difference among the different isolation sources. All groups of E. coli O157:H7 strains showed more than 1.8- to 4.5-log reduction at pH 3.3 and 30 degrees C after 25 min. Significantly reduced (less than 1-log reduction) lethality for all E. coli O157:H7 strain mixtures was observed when pH increased to 3.7 or 4.3, with little difference in acetic acid resistance among the groups. The addition of glutamate to the acetic acid solution or anaerobic incubation provided the best protection compared with the above conditions for all groups of isolates. These results suggest that temperature, pH, and atmospheric conditions are key factors in establishing strategies for improving the safety of acidified foods.}, number={3}, journal={JOURNAL OF FOOD PROTECTION}, author={Oh, Deog-Hwan and Pan, Youwen and Berry, Elaine and Cooley, Michael and Mandrell, Robert and Breidt, Frederick, Jr.}, year={2009}, month={Mar}, pages={503–509} }
 @article{kreske_bjornsdottir_breidt_hassan_2008, title={Effects of pH, Dissolved Oxygen, and Ionic Strength on the Survival of Escherichia coli O157:H7 in Organic Acid Solutions}, volume={71}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-71.12.2404}, abstractNote={The ability of Escherichia coli O157:H7 to survive in acidified vegetable products is of concern because of previously documented outbreaks associated with fruit juices. A study was conducted to determine the survival of E. coli O157:H7 in organic acids at pH values typical of acidified vegetable products (pH 3.2 and 3.7) under different dissolved oxygen conditions (< or = 0.05 and 5 mg/liter) and a range of ionic strengths (0.086 to 1.14). All solutions contained 20 mM gluconic acid, which was used as a noninhibitory low pH buffer to compare the individual acid effect to that of pH alone on the survival of E. coli O157:H7. E. coli O157:H7 cells challenged in buffered solution with ca. 5-mg/liter dissolved oxygen (present in tap water) over a range of ionic strengths at pH 3.2 exhibited a decrease in survival over 6 h at 30 degrees C as the ionic strength was increased. Cells challenged in 40 mM protonated L-lactic and acetic acid solutions with ionic strength of 0.684 achieved a > 4.7-log CFU/ml reduction at pH 3.2. However, under oxygen-limiting conditions in an anaerobic chamber, with < or = 0.05-mg/ liter oxygen, E. coli O157:H7 cells showed < or = 1.55-log CFU/ml reduction regardless of pH, acid type, concentration, or ionic strength. Many acid and acidified foods are sold in hermetically sealed containers with oxygen-limiting conditions. Our results demonstrate that E. coli O157:H7 may survive better than previously expected from studies with acid solutions containing dissolved oxygen.}, number={12}, journal={JOURNAL OF FOOD PROTECTION}, author={Kreske, Audrey C. and Bjornsdottir, Kristin and Breidt, Fred, Jr. and Hassan, Hosni}, year={2008}, month={Dec}, pages={2404–2409} }
 @article{gawish_matthews_wafa_breidt_bourham_2007, title={Atmospheric plasma-aided biocidal finishes for nonwoven polypropylene fabrics. I. Synthesis and characterization}, volume={103}, ISSN={["1097-4628"]}, DOI={10.1002/app.24021}, abstractNote={Novel biocidal fabrics were synthesized by the graft copolymerization of glycidyl methacrylate (GMA) onto plasma-treated nonwoven polypropylene (PP) to produce PP/GMA grafts. Atmospheric oxygenated helium plasma was used to enhance the PP fabrics' initiation before GMA grafting. The grafted PP/GMA epoxide group was reacted with β-cyclodextrin, monochlorotrizynyl-β-cyclodextrins, or a quaternary ammonium chitosan derivative [N-(2 hydroxy propyl) 3-trimethylammonium chitosan chloride]. Some interesting biocidal agents were complexed into the cyclodextrin (CD) cavity of PP/GMA/CD grafted fabrics. Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and optical and scanning electron microscopies were used to characterize the grafted complexed fabrics. These synthesized biocidal fabrics proved to be antistatic, antimicrobial, and insect-repelling (see part II of this study). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1900–1910, 2007}, number={3}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, author={Gawish, S. M. and Matthews, S. R. and Wafa, D. M. and Breidt, F. and Bourham, M. A.}, year={2007}, month={Feb}, pages={1900–1910} }
 @article{wafa_breidt_gawish_matthews_donohue_roe_bourham_2007, title={Atmospheric plasma-aided biocidal finishes for nonwoven polypropylene fabrics. II. Functionality of synthesized fabrics}, volume={103}, ISSN={["1097-4628"]}, DOI={10.1002/app.24042}, abstractNote={Atmospheric plasma-aided graft copolymerization of textile materials provides single or multiple functionality polypropylene (PP) modified fabrics. Biocidal PP's are modified ones to kill or inhibit the growth of microorganisms such as bacteria, molds, and fungi, and insect and tick repelling action. Novel PP biocidal fabrics synthesized by graft copolymerization using plasma-aided technique (see part I of this study) using antibacterial and insect repellent agents have been tested and evaluated and proved to be antimicrobial, tick repellent, and antistatic. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1911–1917, 2007}, number={3}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, author={Wafa, D. M. and Breidt, F. and Gawish, S. M. and Matthews, S. R. and Donohue, K. V. and Roe, R. M. and Bourham, M. A.}, year={2007}, month={Feb}, pages={1911–1917} }
 @article{plengvidhya_breidt_lu_fleming_2007, title={DNA fingerpnntmg of lactic acid bacteria in sauerkraut fermentations}, volume={73}, ISSN={["0099-2240"]}, DOI={10.1128/AEM.01342-07}, abstractNote={ABSTRACT Previous studies using traditional biochemical identification methods to study the ecology of commercial sauerkraut fermentations revealed that four species of lactic acid bacteria, Leuconostoc mesenteroides, Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus brevis, were the primary microorganisms in these fermentations. In this study, 686 isolates were collected from four commercial fermentations and analyzed by DNA fingerprinting. The results indicate that the species of lactic acid bacteria present in sauerkraut fermentations are more diverse than previously reported and include Leuconostoc citreum, Leuconostoc argentinum, Lactobacillus paraplantarum, Lactobacillus coryniformis, and Weissella sp. The newly identified species Leuconostoc fallax was also found. Unexpectedly, only two isolates of P. pentosaceus and 15 isolates of L. brevis were recovered during this study. A better understanding of the microbiota may aid in the development of low-salt fermentations, which may have altered microflora and altered sensory characteristics.}, number={23}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Plengvidhya, Vethachai and Breidt, Fredrick, Jr. and Lu, Zhongjing and Fleming, Henry P.}, year={2007}, month={Dec}, pages={7697–7702} }
 @article{yoon_barrangou-poueys_breidt_fleming_2007, title={Detection and characterization of a lytic Pediococcus bacteriophage from the fermenting cucumber brine}, volume={17}, number={2}, journal={Journal of Microbiology and Biotechnology}, author={Yoon, S. S. and Barrangou-Poueys, R. and Breidt, F. and Fleming, H. P.}, year={2007}, pages={262–270} }
 @article{breidt_hayes_mcfeeters_2007, title={Determination of 5-log reduction times for food pathogens in acidified cucumbers during storage at 10 and 25 degrees C}, volume={70}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-70.11.2638}, abstractNote={Outbreaks of acid-resistant foodborne pathogens in acid foods with pH values below 4.0, including apple cider and orange juice, have raised concerns about the safety of acidified vegetable products. For acidified vegetable products with pH values between 3.3 and 4.6, previous research has demonstrated that thermal treatments are needed to achieve a 5-log reduction in the numbers of Escherichia coli O157:H7, Listeria monocytogenes, or Salmonella enterica. For some acidified vegetable products with a pH of 3.3 or below, heat processing can result in unacceptable product quality. The purpose of this study was to determine the holding times needed to achieve a 5-log reduction in E. coli O157:H7, L. monocytogenes, and S. enterica strains in acidified vegetable products with acetic acid as the primary acidulant, a pH of 3.3 or below, and a minimum equilibrated temperature of 10 degrees C. We found E. coli O157:H7 to be the most acid-resistant microorganism for the conditions tested, with a predicted time to achieve a 5-log reduction in cell numbers at 10 degrees C of 5.7 days, compared with 2.1 days (51 h) for Salmonella or 0.5 days (11.2 h) for Listeria. At 25 degrees C, the E. coli O157:H7 population achieved a 5-log reduction in 1.4 days (34.3 h).}, number={11}, journal={JOURNAL OF FOOD PROTECTION}, author={Breidt, Fred, Jr. and Hayes, Janet and McFeeters, Roger F.}, year={2007}, month={Nov}, pages={2638–2641} }
 @article{pan_breidt_2007, title={Enumeration of viable Listeria monocytogenes cells by real-time PCR with propidium monoazide and ethidium monoazide in the presence of dead cells}, volume={73}, ISSN={["0099-2240"]}, DOI={10.1128/AEM.01198-07}, abstractNote={ABSTRACT Propidium monoazide (PMA) and ethidium monoazide were used for enumeration of viable Listeria monocytogenes cells in the presence of dead cells. PMA had no antimicrobial effect on L. monocytogenes. Viable cell counts were linearly related to real-time PCR threshold cycle values for PMA-treated cells from planktonic and biofilm sources over a 4-log range.}, number={24}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Pan, Y. and Breidt, F., Jr.}, year={2007}, month={Dec}, pages={8028–8031} }
 @article{perez-diaz_kelling_hale_breidt_mcfeeters_2007, title={Lactobacilli and tartrazine as causative a agents of red-color spoilage in cucumber pickle products}, volume={72}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2007.00460.x}, abstractNote={The cucumber pickling industry has sporadically experienced spoilage outbreaks in pickled cucumber products characterized by development of red color on the surface of the fruits. Lactobacillus casei and Lactobacillus paracasei were isolated from 2 outbreaks of this spoilage that occurred about 15 y apart during the last 3 decades. Both organisms were shown to produce this spoilage when inoculated into pickled cucumbers while concomitantly degrading the azo dye tartrazine (FD&C yellow nr 5). This food dye is used as a yellow coloring in the brine cover solutions of commercial pickled cucumber products. The red color does not occur in the absence of tartrazine, nor when turmeric is used as a yellow coloring in the pickles. Addition of sodium benzoate to the brine cover solutions of a pickled cucumber product, more specifically hamburger dill pickles, prevented growth of these lactic acid bacteria and the development of the red spoilage.}, number={7}, journal={JOURNAL OF FOOD SCIENCE}, author={Perez-Diaz, I. M. and Kelling, R. E. and Hale, S. and Breidt, F. and McFeeters, R. F.}, year={2007}, month={Sep}, pages={M240–M245} }
 @article{gawish_ramadan_cornelius_bourham_matthews_mccord_wafa_breidt_2007, title={New functionalities of PA6,6 fabric modified by atmospheric pressure plasma and grafted glycidyl methacrylate derivatives}, volume={77}, ISSN={["1746-7748"]}, DOI={10.1177/0040517507076747}, abstractNote={Oxidative atmospheric pressure plasma was utilized to activate surface of PA 6,6 fabrics followed by graft copolymerization of glycidyl methacrylate (GMA) and further reacted with triethylene tetramine (TETA), quaternary ammonium chitosan (HTCC) or β-cyclodextrin (β-CD). The inner CD cavity was complexed with some insecticidal perfumes. Modified PA6,6 fabrics were analyzed by differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy and scanning electron microscopy. Antimicrobial activity and insect repelling assay were conducted and showed efficient antimicrobial and insect repelling properties.}, number={2}, journal={TEXTILE RESEARCH JOURNAL}, author={Gawish, S. M. and Ramadan, A. M. and Cornelius, C. E. and Bourham, M. A. and Matthews, S. R. and McCord, M. G. and Wafa, D. M. and Breidt, F.}, year={2007}, month={Feb}, pages={92–104} }
 @article{makarova_slesarev_wolf_sorokin_mirkin_koonin_pavlov_pavlova_karamychev_polouchine_et al._2006, title={Comparative genomics of the lactic acid bacteria}, volume={103}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.0607117103}, abstractNote={Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.}, number={42}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, publisher={Proceedings of the National Academy of Sciences}, author={Makarova, K. and Slesarev, A. and Wolf, Y. and Sorokin, A. and Mirkin, B. and Koonin, E. and Pavlov, A. and Pavlova, N. and Karamychev, V. and Polouchine, N. and et al.}, year={2006}, month={Oct}, pages={15611–15616} }
 @article{chin_breidt_fleming_shin_yoon_2006, title={Identifications of predominant bacterial isolates from the fermenting kimchi using ITS-PCR and partial 16S rDNA sequence analyses}, volume={16}, number={1}, journal={Journal of Microbiology and Biotechnology}, author={Chin, H. S. and Breidt, F. and Fleming, H. P. and Shin, W. C. and Yoon, S. S.}, year={2006}, pages={68–76} }
 @article{bjornsdottir_breidt_mcfeeters_2006, title={Protective effects of organic acids on survival of Escherichia coli O157 : H7 in acidic environments}, volume={72}, ISSN={["1098-5336"]}, DOI={10.1128/aem.72.1.660-664.2006}, abstractNote={ABSTRACT}, number={1}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Bjornsdottir, K and Breidt, F and McFeeters, RF}, year={2006}, month={Jan}, pages={660–664} }
 @article{mudgal_breidt_lubkin_sandeep_2006, title={Quantifying the significance of phage attack on starter cultures: a mechanistic model for population dynamics of phage and their hosts isolated from fermenting sauerkraut}, volume={72}, ISSN={["1098-5336"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000238620100013&KeyUID=WOS:000238620100013}, DOI={10.1128/AEM.02429-05}, abstractNote={ABSTRACT}, number={6}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Mudgal, P. and Breidt, F., Jr. and Lubkin, S. R. and Sandeep, K. P.}, year={2006}, month={Jun}, pages={3908–3915} }
 @article{pan_breidt_kathariou_2006, title={Resistance of Listeria monocytogenes biofilms to sanitizing agents in a simulated food processing environment}, volume={72}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.01065-06}, abstractNote={ABSTRACT The objective of this study was to evaluate the resistance of biofilms of Listeria monocytogenes to sanitizing agents under laboratory conditions simulating a food processing environment. Biofilms were initially formed on stainless steel and Teflon coupons using a five-strain mixture of L. monocytogenes. The coupons were then subjected to repeated 24-h daily cycles. Each cycle consisted of three sequential steps: (i) a brief (60 s) exposure of the coupons to a sanitizing agent (a mixture of peroxides) or saline as a control treatment, (ii) storage of the coupons in sterile plastic tubes without any nutrients or water for 15 h, (iii) and incubation of the coupons in diluted growth medium for 8 h. This regimen was repeated daily for up to 3 weeks and was designed to represent stresses encountered by bacteria in a food processing environment. The bacteria on the coupons were reduced in number during the first week of the simulated food processing (SFP) regimen, but then adapted to the stressful conditions and increased in number. Biofilms repeatedly exposed the peroxide sanitizer in the SFP regimen developed resistance to the peroxide sanitizer as well as other sanitizers (quaternary ammonium compounds and chlorine). Interestingly, cells that were removed from the biofilms on peroxide-treated and control coupons were not significantly different in their resistance to sanitizing agents. These data suggest that the resistance of the treated biofilms to sanitizing agents may be due to attributes of extracellular polymeric substances and is not an intrinsic attribute of the cells in the biofilm.}, number={12}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Pan, Y. and Breidt, F., Jr. and Kathariou, S.}, year={2006}, month={Dec}, pages={7711–7717} }
 @article{dougherty_ramos da conceicao neta_mcfeeters_lubkin_breidt_2006, title={Semi-mechanistic partial buffer approach to modeling pH, the buffer properties, and the distribution of ionic species in complex solutions}, volume={54}, ISSN={["1520-5118"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000239454700045&KeyUID=WOS:000239454700045}, DOI={10.1021/jf0531508}, abstractNote={In many biological science and food processing applications, it is very important to control or modify pH. However, the complex, unknown composition of biological media and foods often limits the utility of purely theoretical approaches to modeling pH and calculating the distributions of ionizable species. This paper provides general formulas and efficient algorithms for predicting the pH, titration, ionic species concentrations, buffer capacity, and ionic strength of buffer solutions containing both defined and undefined components. A flexible, semi-mechanistic, partial buffering (SMPB) approach is presented that uses local polynomial regression to model the buffering influence of complex or undefined components in a solution, while identified components of known concentration are modeled using expressions based on extensions of the standard acid-base theory. The SMPB method is implemented in a freeware package, (pH)Tools, for use with Matlab. We validated the predictive accuracy of these methods by using strong acid titrations of cucumber slurries to predict the amount of a weak acid required to adjust pH to selected target values.}, number={16}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Dougherty, Daniel P. and Ramos Da Conceicao Neta, Edith and McFeeters, Roger F. and Lubkin, Sharon R. and Breidt, Frederick, Jr.}, year={2006}, month={Aug}, pages={6021–6029} }
 @article{breidt_hayes_osborne_mcfeeters_2005, title={Determination of 5-log pathogen reduction times for heat-processed, acidified vegetable brines}, volume={68}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-68.2.305}, abstractNote={Recent outbreaks of acid-resistant food pathogens in acid foods, including apple cider and orange juice, have raised concerns about the safety of acidified vegetable products. We determined pasteurization times and temperatures needed to assure a 5-log reduction in the numbers of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella strains in acidified cucumber pickle brines. Cocktails of five strains of each pathogen were (separately) used for heat-inactivation studies between 50 and 60 degrees C in brines that had an equilibrated pH value of 4.1. Salmonella strains were found to be less heat resistant than E. coli O157:H7 or L. monocytogenes strains. The nonlinear killing curves generated during these studies were modeled using a Weibull function. We found no significant difference in the heat-killing data for E. coli O157:H7 and L. monocytogenes (P = 0.9709). The predicted 5-log reduction times for E. coli O157:H7 and L. monocytogenes were found to fit an exponential decay function. These data were used to estimate minimum pasteurization times and temperatures needed to ensure safe processing of acidified pickle products and show that current industry pasteurization practices offer a significant margin of safety.}, number={2}, journal={JOURNAL OF FOOD PROTECTION}, author={Breidt, F and Hayes, JS and Osborne, JA and McFeeters, RF}, year={2005}, month={Feb}, pages={305–310} }
 @article{mattos_fasina_reina_fleming_breidt_damasceno_passos_2005, title={Heat transfer and microbial kinetics modeling to determine the location of microorganisms within cucumber fruit}, volume={70}, ISSN={["1750-3841"]}, DOI={10.1111/j.1365-2621.2005.tb09972.x}, abstractNote={ABSTRACT:  Microbiological and modeling (combined heat transfer and microbial kinetic equations [HTMK] model) approaches were used to determine the location of microorganisms within cucumber. The total number of aerobes found within/on cucumbers varied from 105 to 107 colony‐forming units (CFU) /g. The highest and the least amount of microbiota were respectively found at the blossom end and middle part of the cucumbers and were within the 1st 6 mm of the cucumber surface. A comparison of the calculated thermal death time from the HTMK model with the values obtained from experimental data showed that total aerobic microorganisms were located within 0.65 mm of the fruit surface.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={Mattos, FR and Fasina, OO and Reina, LD and Fleming, HP and Breidt, F and Damasceno, GS and Passos, FV}, year={2005}, pages={E324–E330} }
 @article{reina_breidt_fleming_kathariou_2005, title={Isolation and selection of lactic acid bacteria as biocontrol agents for nonacidified, refrigerated pickles}, volume={70}, ISSN={["1750-3841"]}, DOI={10.1111/j.1365-2621.2005.tb09050.x}, abstractNote={AB isolates w AB isolates w AB isolates w AB isolates were obtained. Among the L e obtained. Among the L e obtained. Among the L e obtained. Among the L e obtained. Among the LAB identified w AB identified w AB identified w}, number={1}, journal={JOURNAL OF FOOD SCIENCE}, author={Reina, LD and Breidt, F and Fleming, HP and Kathariou, S}, year={2005}, pages={M7–M11} }
 @article{breidt_2004, title={A genomic study of Leuconostoc mesenteroides and the molecular ecology of sauerkraut fermentations}, volume={69}, DOI={10.1111/j.1365-2621.2004.tb17874.x}, abstractNote={ABSTRACT:  Most vegetable fermentations are carried out without the use of starter cultures, using a technology that has remained virtually unchanged for centuries. As the scale of industrial vegetable fermentations increases worldwide, the disposal of salt (chloride) waste, which is generated during processing of these products, has become a major problem. The development of new technology to reduce the amount of salt used in vegetable fermentations may require a greater understanding of the microbial ecology of these fermentations, and may also require the use of starter cultures.}, number={1}, journal={Journal of Food Science}, author={Breidt, F.}, year={2004}, pages={210–212} }
 @article{breidt_hayes_mcfeeters_2004, title={Independent effects of acetic acid and pH on survival of Escherichia coli in simulated acidified pickle products}, volume={67}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x-67.1.12}, abstractNote={Our objective was to determine the effects of organic acids and pH on the rate at which selected strains of Escherichia coli O157:H7 die in acid solutions representative of acidified pickle products (pH < 4.6). We used gluconic acid/sodium gluconate (pKa = 3.7) as a noninhibitory buffer to maintain pH at selected values in the absence of other organic acids. This was possible because we found that the inhibitory effects of this acid on E. coli strains at pH 3.1 were independent of acid concentration over a range of 2 to 200 mM. By this method, the lethal effects of acetic acid solutions (100 to 400 mM) at selected pH values between 3.1 and 4.1 were compared with the effects of pH alone (as determined using gluconate buffer). We found D-values were two- to fourfold lower with acetic acid compared with the effect of pH alone for simulated pickle brines in this pH range. Glutamic acid, an amino acid that is known to enhance acid resistance in E. coli and is a component of pickle brines, protected the E. coli strains from the specific effects of acetic acid.}, number={1}, journal={JOURNAL OF FOOD PROTECTION}, author={Breidt, F and Hayes, JS and McFeeters, RF}, year={2004}, month={Jan}, pages={12–18} }
 @article{johanningsmeier_fleming_breidt_2004, title={Malolactic activity of lactic acid bacteria during sauerkraut fermentation}, volume={69}, ISSN={["1750-3841"]}, DOI={10.1111/j.1365-2621.2004.tb09891.x}, abstractNote={ABSTRACT:  The frequency of lactic acid bacteria (LAB) involved in sauerkraut fermentation with (MDC+) or without (MDC‐) the ability to decarboxylate malic acid was determined. The MDC+ phenotype was found in > 99% of homofermentative LAB isolated from commercial fermentations. In contrast, heterofermentative LAB isolates from 0.25, 3, 7, and 10 d had only 53%, 54%, 15%, and 11% MDC+ phenotype, respectively, indicating that more than 1 strain or species was involved. The malolactic reaction was demonstrated in cabbage juice with known strains of Leuconostoc mesenteroides, raising the question of desirability of such activity in cultures selected for the controlled fermentation of cabbage.}, number={8}, journal={JOURNAL OF FOOD SCIENCE}, author={Johanningsmeier, SD and Fleming, HP and Breidt, F}, year={2004}, month={Oct}, pages={M222–M227} }
 @article{plengvidhya_breidt_fleming_2004, title={Use of RAPD-PCR as a method to follow the progress of starter cultures in sauerkraut fermentation}, volume={93}, ISSN={["1879-3460"]}, DOI={10.1016/j.ijfoodmicro.2003.11.010}, abstractNote={DNA fingerprinting methods were used to follow the progress of unmarked starter cultures in laboratory sauerkraut fermentations (1.2 and 13 l). Random prime PCR (RAPD-PCR) was used for strain-specific identification of Leuconostoc mesenteroides cultures. A comparative analysis of RAPD banding patterns for fermentation isolates and starter cultures was carried out using both genetically marked and unmarked cultures. While some variation in the RAPD patterns was observed, the results showed that the starter cultures dominated the fermentation during early heterofermentative stage for up to 5 days after the start of fermentation. Results from marked and unmarked starter cultures were confirmed by intergenic transcribed spacer (ITS)-PCR, and strain identify was confirmed by pulse field gel electrophoresis (PFGE) patterns. The results demonstrate the utility of RAPD to follow the progression of unmarked starter cultures of L. mesenteroides in sauerkraut fermentations.}, number={3}, journal={INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY}, author={Plengvidhya, V and Breidt, F and Fleming, HP}, year={2004}, month={Jun}, pages={287–296} }
 @article{lu_breidt_plengvidhya_fleming_2003, title={Bacteriophage ecology in commercial sauerkraut fermentations}, volume={69}, ISSN={["0099-2240"]}, DOI={10.1128/AEM.69.6.3192-3202.2003}, abstractNote={ABSTRACT}, number={6}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Lu, Z and Breidt, F and Plengvidhya, V and Fleming, HP}, year={2003}, month={Jun}, pages={3192–3202} }
 @article{lu_breidt_fleming_altermann_klaenhammer_2003, title={Isolation and characterization of a Lactobacillus plantarum bacteriophage, Phi JL-1, from a cucumber fermentation}, volume={84}, ISSN={["1879-3460"]}, DOI={10.1016/S0168-1605(03)00111-9}, abstractNote={A virulent Lactobacillus plantarum bacteriophage, PhiJL-1, was isolated from a commercial cucumber fermentation. The phage was specific for two related strains of L. plantarum, BI7 and its mutant (deficient in malolactate fermenting ability) MU45, which have been evaluated as starter cultures for controlled cucumber fermentation and as biocontrol microorganisms for minimally processed vegetable products. The phage genome of PhiJL-1 was sequenced to reveal a linear, double-stranded DNA (36.7 kbp). Sodium dodecyl sulfate-polyacryamide gel electrophoresis (SDS-PAGE) profiles indicated that PhiJL-1 contains six structural proteins (28, 34, 45, 50, 61, and 76 kDa). Electron microscopy revealed that the phage has an isometric head (59 nm in diameter), a long non-contractile tail (182 nm in length and 11 nm in width), and a complex base plate. The phage belongs to the Bradley group B1 or Siphoviridae family. One-step growth kinetics of the phage showed that the latent period was 35 min, the rise period was 40 min, and the average burst size was 22 phage particles/infected cell. Phage particles (90%) adsorbed to the host cells 20 min after infection. Calcium supplementation (up to 30 mM CaCl(2)) in MRS media did not affect the first cycle of phage adsorption, but promoted rapid phage propagation and cell lysis in the infection cycle subsequent to adsorption. The D values of PhiJL-1 at pH 6.5 were estimated to be 2.7 min at 70 degrees C and 0.2 min at 80 degrees C by a thermal inactivation experiment. Knowledge of the properties of L. plantarum bacteriophage PhiJL-1 may be important for the development of controlled vegetable fermentations.}, number={2}, journal={INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY}, author={Lu, Z and Breidt, F and Fleming, HP and Altermann, E and Klaenhammer, TR}, year={2003}, month={Jul}, pages={225–235} }
 @article{reina_fleming_breidt_2002, title={Bacterial contamination of cucumber fruit through adhesion}, volume={65}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-65.12.1881}, abstractNote={In this study, the adhesion of bacteria to fresh cucumber surfaces in aqueous suspension was shown to be dependent on time of incubation, inoculum species and concentration, and temperature. The adhesion of bacteria to the fruit in wash water was less extensive at lower temperatures and shorter exposure times. Various species of bacteria were adsorbed to cucumber surfaces in the following relative order: Salmonella Typhimurium > Staphylococcus aureus > Lactobacillus plantarum > Listeria monocytogenes. Cells were adsorbed at all temperatures tested (5, 15, 25, and 35 degrees C) at levels that depended on incubation time, but the numbers of cells adsorbed were larger at higher incubation temperatures. Levels of adhesion of bacteria to dewaxed fruit were higher for L. monocytogenes and lower for Salmonella Typhimurium, L. plantarum, and S. aureus than were levels of adhesion to waxed fruit.}, number={12}, journal={JOURNAL OF FOOD PROTECTION}, author={Reina, LD and Fleming, HP and Breidt, F}, year={2002}, month={Dec}, pages={1881–1887} }
 @article{barrangou_yoon_breidt_fleming_klaenhammer_2002, title={Characterization of six Leuconostoc fallax bacteriophages isolated from an industrial sauerkraut fermentation}, volume={68}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.68.11.5452-5458.2002}, abstractNote={ABSTRACT}, number={11}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, publisher={American Society for Microbiology}, author={Barrangou, R and Yoon, SS and Breidt, F and Fleming, HP and Klaenhammer, TR}, year={2002}, month={Nov}, pages={5452–5458} }
 @article{klaenhammer_altermann_arigoni_bolotin_breidt_broadbent_cano_chaillou_deutscher_gasson_et al._2002, title={Discovering lactic acid bacteria by genomics}, volume={82}, DOI={10.1007/978-94-017-2029-8_3}, abstractNote={This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, environmental habitat, and its role in fermentation, bioprocessing, or probiotics. For those projects where genome sequence data were available by March 2002, summaries include a listing of key statistics and interesting genomic features. These efforts will revolutionize our molecular view of Gram-positive bacteria, as up to 15 genomes from the low GC content lactic acid bacteria are expected to be available in the public domain by the end of 2003. Our collective view of the lactic acid bacteria will be fundamentally changed as we rediscover the relationships and capabilities of these organisms through genomics.}, number={1-4}, journal={Antonie Van Leeuwenhoek}, author={Klaenhammer, T. and Altermann, E. and Arigoni, F. and Bolotin, A. and Breidt, F. and Broadbent, J. and Cano, R. and Chaillou, S. and Deutscher, J. and Gasson, M. and et al.}, year={2002}, pages={29–58} }
 @article{dougherty_breidt_mcfeeters_lubkin_2002, title={Energy-based dynamic model for variable temperature batch fermentation by Lactococcus lactis}, volume={68}, ISSN={["0099-2240"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000175407300048&KeyUID=WOS:000175407300048}, DOI={10.1128/AEM.68.5.2468-2478.2002}, abstractNote={ABSTRACT}, number={5}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Dougherty, DP and Breidt, F and McFeeters, RF and Lubkin, SR}, year={2002}, month={May}, pages={2468–2478} }
 @article{barrangou_yoon_breidt_fleming_klaenhammer_2002, title={Identification and characterization of Leuconostoc fallax strains isolated from an industrial sauerkraut fermentation}, volume={68}, ISSN={["0099-2240"]}, DOI={10.1128/AEM.68.6.2877-2884.2002}, abstractNote={ABSTRACT}, number={6}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, publisher={American Society for Microbiology}, author={Barrangou, R and Yoon, SS and Breidt, F and Fleming, HP and Klaenhammer, TR}, year={2002}, month={Jun}, pages={2877–2884} }
 @article{yoon_barrangou-poueys_breidt_klaenhammer_fleming_2002, title={Isolation and characterization of bacteriophages from fermenting sauerkraut}, volume={68}, ISSN={["0099-2240"]}, DOI={10.1128/AEM.68.2.973-976.2002}, abstractNote={ABSTRACT}, number={2}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, publisher={American Society for Microbiology}, author={Yoon, SS and Barrangou-Poueys, R and Breidt, F and Klaenhammer, TR and Fleming, HP}, year={2002}, month={Feb}, pages={973–976} }
 @article{yoon_kim_breidt_fleming_2001, title={Characterization of a lytic Lactobacillus plantarum bacteriophage and molecular cloning of a lysin gene in Escherichia coli}, volume={65}, ISSN={["1879-3460"]}, DOI={10.1016/S0168-1605(00)00498-0}, abstractNote={Bacteriophage SC921, which can infect Lactobacillus plantarum specifically, was isolated from a fermented vegetable source, Kimchi. This phage is active against six of 11 strains of L. plantarum tested as hosts. Morphologically, it has an isometric head (60 nm in diameter) and a non-contractile tail (260 nm long and 9-11 nm wide), indicating that it belongs to Bradley's group B or the Siphoviridae family according to the International Committee on Taxonomy of Viruses (ICTV). The bouyant density was 1.58 g/cm3. SDS-PAGE experimentation indicated that the phage particle contains two major structural proteins and several minor proteins. The genome was a double stranded linear DNA molecule with cohesive ends and 66.5 kb long by mapping genomic DNA digested with the restriction endonucleases: KpnI, SmaI, and XbaI. The [G + C] content of the phage DNA is 39.4%. For this lysin gene study, 9.4 kb of KpnI-digested DNA fragment was cloned into pUC19 and expressed in Escherichia coli. The KpnI fragment was considered as the genetic element responsible for the lysis gene of L. plantarum bacteriophage. The cloned fragment in pUC19 was hybridized to a 9.4-kb fragment generated by KpnI digestion of SC 921 as a probe. This confirmed that the fragment in pUC19 originated from phage DNA. The lysin gene was near the middle of the phage genome.}, number={1-2}, journal={INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY}, author={Yoon, SS and Kim, JW and Breidt, F and Fleming, HP}, year={2001}, month={Apr}, pages={63–74} }
 @article{unal_fleming_mcfeeters_thompson_breidt_giesbrecht_2001, title={Novel quantitative assays for estimating the antimicrobial activity of fresh garlic juice}, volume={64}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-64.2.189}, abstractNote={Novel agar diffusion and broth dilution assays were developed for quantitatively estimating the antimicrobial activity of fresh garlic juice. Bacteria found to be inhibited by garlic juice in agar diffusion assay included two gram-positive and five gram-negative species. Leuconostoc mesenteroides was not inhibited. Escherichia coli B-103 (HB101, with pJH101, ampicillin resistant, 100 microg ml(-1)) was inhibited and chosen as the standard culture for quantitative assays. The agar diffusion assay was based on the slope ratio method, where the slope of dose response for garlic juice was divided by the slope of dose response for methylmethane thiosulfonate (MMTSO2). Juice from fresh garlic varied in activity between 1.76 and 2.31 microg of MMTSO2 per mg of garlic juice. The activity of juice decreased during 11 months of storage of garlic cloves at 5 degrees C from 2.31 to less than 0.1 microg of MMTSO2 per mg of juice. The broth dilution assay also used the E. coli B-103 culture, which permitted selective enumeration of this bacterium when 100 microg ml(-1) of ampicillin was incorporated into the enumerating agar. Selective enumeration was essential since the garlic juice was not sterile and, thus, contained natural flora. Growth of E. coli was unaffected by 0.1%, delayed by 0.25%, and completely inhibited at 0.5 and 2% garlic juice in broth during 24 h of incubation at 37 micro C. The minimum inhibition concentration of garlic juice by broth dilution assay was, thus, estimated to be 0.5%, which is equivalent to 3.46 microg of MMTSO2 per mg of garlic juice by the agar diffusion assay.}, number={2}, journal={JOURNAL OF FOOD PROTECTION}, author={Unal, R and Fleming, HP and McFeeters, RF and Thompson, RL and Breidt, F and Giesbrecht, FG}, year={2001}, month={Feb}, pages={189–194} }
 @article{breidt_hayes_fleming_2000, title={Reduction of microflora of whole pickling cucumbers by blanching}, volume={65}, ISSN={["0022-1147"]}, DOI={10.1111/j.1365-2621.2000.tb10611.x}, abstractNote={ABSTRACT:}, number={8}, journal={JOURNAL OF FOOD SCIENCE}, author={Breidt, F and Hayes, JS and Fleming, HP}, year={2000}, pages={1354–1358} }
 @article{shofran_purrington_breidt_fleming_1998, title={Antimicrobial properties of sinigrin and its hydrolysis products}, volume={63}, DOI={10.1111/j.1365-2621.1998.tb15798.x}, abstractNote={ABSTRACT}, number={4}, journal={Journal of Food Science}, author={Shofran, B. G. and Purrington, S. T. and Breidt, F. and Fleming, H. P.}, year={1998}, pages={621–624} }
 @article{chung_breidt_dubnau_1998, title={Cell surface localization and processing of the ComG proteins, required for DNA binding during transformation of Bacillus subtilis}, volume={29}, ISSN={["0950-382X"]}, DOI={10.1046/j.1365-2958.1998.00989.x}, abstractNote={The comG operon of Bacillus subtilis encodes seven proteins essential for the binding of transforming DNA to the competent cell surface. We have explored the processing of the ComG proteins and the cellular localization of six of them. All of the proteins were found to be membrane associated. The four proteins with N‐terminal sequence motifs typical of type 4 prepilins (ComGC, GD, GE and GG) are processed by a pathway that requires the product of comC, also an essential competence gene. The unprocessed forms of ComGC and GD behave like integral membrane proteins. Pre‐ComGG differs from pre‐ComGC and pre‐ComGD, in that it is accessible to proteolysis only from the cytoplasmic face of the membrane and at least a portion of it behaves like a peripheral membrane protein. The mature forms of these proteins are translocated to the outer face of the membrane and are liberated when peptidoglycan is hydrolysed by lysozyme or mutanolysin. ComGG exists in part as a disulphide‐cross‐linked homodimer in vivo. ComGC was found to possess an intramolecular disulphide bond. The previously identified homodimer form of this protein is not stabilized by disulphide bond formation. ComGF behaves as an integral membrane protein, while ComGA, a putative ATPase, is located on the inner face of the membrane as a peripheral membrane protein. Possible roles of the ComG proteins in DNA binding to the competent cell surface are discussed in the light of these and other results.}, number={3}, journal={MOLECULAR MICROBIOLOGY}, author={Chung, YS and Breidt, F and Dubnau, D}, year={1998}, month={Aug}, pages={905–913} }
 @article{breidt_fleming_1998, title={Modeling of the competitive growth of Listeria manocytogenes and Lactococcus lactis in vegetable broth}, volume={64}, number={9}, journal={Applied and Environmental Microbiology}, author={Breidt, F. and Fleming, H. P.}, year={1998}, pages={3159–3165} }
 @inbook{fleming_breidt_costilow_1997, title={Microogranisms and food}, booktitle={Acidified foods: Principles of handling and preservation (2nd ed.)}, publisher={St. Charles, Ill.: Pickle Packers International, Inc.}, author={Fleming, H. P. and Breidt, F. and Costilow, R. N.}, year={1997} }
 @article{breidt_fleming_1997, title={Using lactic acid bacteria to improve the safety of minimally processed fruits and vegetables}, volume={51}, number={9}, journal={Food Technology}, author={Breidt, F. and Fleming, H. P.}, year={1997}, pages={44–464851} }