Journal of food protection最新文献

{"title":"Isolation and Enumeration of the Bacillus cereus Group Using a Chromogenic Substrate that Targets Phosphatidylcholine Phospholipase C Activity.","authors":"Paul Tuan Nguyen, Lawrence Restaino","doi":"10.1016/j.jfp.2024.100376","DOIUrl":"https://doi.org/10.1016/j.jfp.2024.100376","url":null,"abstract":"<p><p>The Bacillus cereus group is comprised of diverse yet closely-related species that are ubiquitous in nature. These Gram-positive, spore-forming bacteria are commonly isolated as potential pathogens in environmental and food samples, and they are also beneficially used in industrial applications such as probiotics or agricultural pesticides. Although phylogenetic and genomic analyses identified eight formally recognized species within the Bacillus cereus group, only five members are currently acknowledged using standardized isolation procedures. Therefore, current enumeration procedures may be inadequate and inaccurate in determining the clinical importance of the B. cereus group and their prevalence in food and environmental sources. In this investigation, the R & F® Bacillus cereus Group Chromogenic Plating Medium (BCG) was developed to target the enzyme phosphatidylcholine phospholipase C (PC-PLC) found widely distributed among the B. cereus group species. The performance evaluations of the plating medium demonstrated 100% plating productivity ratio, inclusivity, and exclusivity when compared with Trypto Soy Agar (TSA). B. cereus group species, including B. anthracis, B. cereus sensu stricto (s.s.), B. cytotoxicus, B. pseudomycoides, B. mycoides, B. thuringiensis, B. toyonensis, B. weidmannii, and B. weihenstephanensis, formed turquoise-colored colonies on the BCG agar, indicating PC-PLC activity after 24-28 hour of incubation at the selected optimal temperature of 35°C. Furthermore, no significant difference was observed between BCG and TSA when enumerating B. cereus s.s. and B. cytotoxicus artificially inoculated in whey protein powder and ultra-high temperature milk after long-term storage.</p>","PeriodicalId":15903,"journal":{"name":"Journal of food protection","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142406489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hazard characterization of antibiotic-resistant Aeromonas spp. isolated from mussel and oyster shellstock available for retail purchase in Canada.","authors":"Mary Rao, Januana S Teixeira, Annika Flint, Sandeep Tamber","doi":"10.1016/j.jfp.2024.100374","DOIUrl":"https://doi.org/10.1016/j.jfp.2024.100374","url":null,"abstract":"<p><p>Surveillance and monitoring of foods for the presence of antimicrobial-resistant (AMR) bacteria is required to assess the risks these bacteria pose to human health. Frequently consumed raw or lightly cooked, live bivalve shellfish such as mussels and oysters can be a source of exposure to AMR bacteria. This study sought to determine the prevalence of third generation cephalosporin (3GC) and carbapenem resistant bacteria in live mussel and oyster shellstock available for retail purchase through the course of one calendar year. Just over half of the 180 samples (52%) tested positive for the presence 3GC-resistant bacteria belonging to thirty distinct bacterial species. Speciation of the isolates was carried out using the Bruker MALDI Biotyper. Serratia spp., Aeromonas spp., and Rahnella spp. were the most frequently isolated groups of bacteria. Antibiotic resistance testing confirmed reduced susceptibility for 3GCs and/or carbapenems in 15 of the 29 Aeromonas isolates. Based on AMR patterns, and species identity, a sub-set of ten Aeromonas strains was chosen for further characterization by whole genome sequence analysis. Genomic analysis revealed the presence of multiple antibiotic resistance and virulence genes. A number of mobile genetic elements were also identified indicating the potential for horizontal gene transfer. Differences in gene detection by the bioinformatic tools and databases used (ResFinder. CARD RGI, PlasmidFinder, and MobSuite) are discussed. This study highlights the strengths and limitations of using genomics tools to perform hazard characterization of diverse foodborne bacterial species.</p>","PeriodicalId":15903,"journal":{"name":"Journal of food protection","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142391042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of a postbiotic on Salmonella enterica prevalence, serotype diversity, and antimicrobial resistance in the subiliac lymph nodes of cull dairy cattle.","authors":"Stephen E Edache, Vanessa Horton, Diana M Dewsbury, Leigh Ann George, Xiaorong Shi, T G Nagaraja, Sherri Trujillo, Ryan Algino, Tom S Edrington, David G Renter, Natalia Cernicchiaro","doi":"10.1016/j.jfp.2024.100375","DOIUrl":"https://doi.org/10.1016/j.jfp.2024.100375","url":null,"abstract":"<p><p>This study aimed to determine whether the farm-level use of a Saccharomyces cerevisiae-based postbiotic was associated with Salmonella prevalence and concentration, serotype diversity, and antimicrobial resistance in the subiliac lymph nodes (LN) of cull dairy cows. In collaboration with two commercial processing plants in the Southwestern (SW) and Northeastern (NE) regions of the U.S., cull dairy cattle lots processed in the same week from dairy farms that fed or not the postbiotic were sampled. Up to 20 LN were collected from dairy cattle from each supplier farm at least once every season. Samples were analyzed for Salmonella by culture and quantitative PCR methods, and isolates were subjected to serotype identification and antimicrobial susceptibility testing. Although a numerically lower prevalence was observed, the pre-harvest administration of the postbiotic was not significantly associated with Salmonella prevalence in cull dairy cattle. However, Salmonella prevalence significantly varied by region; the SW region showed a higher prevalence than the NE region. Whereas dominant Salmonella serotypes included Montevideo, Mbandaka, Muenster, Cerro, Meleagridis, and Anatum, the probability of isolating a dominant serotype did not significantly vary by feed additive status (FAS) or region, but varied by season. Up to 34 isolates (out of 391) exhibited resistance to each antimicrobial, with the highest number of isolates exhibiting resistance to streptomycin and ciprofloxacin, however, this did not significantly vary by FAS, season, or region. The precise reasons for the lack of effectiveness of the postbiotic in reducing Salmonella burden are unknown, however, varied administration durations of the postbiotic due to culling at different lactation cycle stages or during dry periods may have hindered its impact, especially if dairy cows were culled early. Other factors may include dietary components, farm management practices, and external environmental influences.</p>","PeriodicalId":15903,"journal":{"name":"Journal of food protection","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142391041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Feedlot-level Use of a Direct-fed Microbial on Fecal Shedding of E. coli O157:H7","authors":"","doi":"10.1016/j.jfp.2024.100370","DOIUrl":"10.1016/j.jfp.2024.100370","url":null,"abstract":"<div><div>Our objectives were to determine whether the feedlot-level use of a direct-fed microbial (DFM; <em>Lactobacillus animalis</em> LA51 and <em>Propionibacterium freudenreichii</em> PF24; Bovamine Defend®, 2 × 10⁹ CFU/g) was associated with fecal prevalence and concentration of <em>E. coli</em> O157:H7, and determine pen- and feedlot-level risk factors associated with fecal <em>E. coli</em> O157:H7 prevalence in cattle pens from commercial feedlot operations. Twenty commercial feedlots in Nebraska, ten that included DFM (DFM) and ten that did not (no-DFM), were sampled during the summer of 2017. In each sampling month, 22 pen-floor fecal samples were collected from three pens in each feedlot. Samples were subjected to cultural and molecular procedures for the detection of <em>E. coli</em> O157:H7 (immunomagnetic separation, plating on selective media, followed by PCR confirmation) and spiral plating for quantification. A total of 1,320 samples from 180 pens of finishing cattle belonging to 20 feedlots, which were sampled three times throughout a 12-week period, were processed and tested. Across all feedlots and sampling months, the mean within-pen prevalence was 13.5% (95% CI = 2.6–47.4%). The association between DFM status and the within-pen prevalence of <em>E. coli</em> O157:H7 depended significantly (<em>p</em> &lt; 0.05) on the sampling month. The second sampling month between late July and mid-August corresponded to the highest within-pen prevalence estimates reported in this study, with no-DFM pens having a higher prevalence than DFM pens. After accounting for the DFM status, and based on multivariable analyses, sampling month, average pen body weight, and weather conditions were significantly associated with the within-pen fecal prevalence of <em>E. coli</em> O157:H7. Collectively, these findings demonstrate that the use of a DFM containing <em>Lactobacillus animalis</em> LA51 and <em>Propionibacterium freudenreichii</em> PF26 in feedlots showed potential in reducing fecal <em>E. coli</em> O157:H7 prevalence in cattle during times when prevalence peaks.</div></div>","PeriodicalId":15903,"journal":{"name":"Journal of food protection","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142391043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generic Food Safety Assessment: A Framework to Evaluate Food Safety Hazards Emerging from Change(s) in the Primary Production System – A Case Study Involving Intercropping","authors":"","doi":"10.1016/j.jfp.2024.100371","DOIUrl":"10.1016/j.jfp.2024.100371","url":null,"abstract":"<div><div>Food safety is a shared responsibility of all actors along the food supply chain. Changes in the primary production system can affect food safety hazards along the supply chain. This highlights the need for a framework that enables primary producers (i.e., farmers) to assess the potential food safety hazards and, if needed, to apply control measures. This paper presents a generic food safety assessment (GFSA) framework that has been developed based on Hazard Analysis and Critical Control Point (HACCP). The proposed framework was applied to a case study, i.e., the transition from sole cropping of oats to intercropping of oats with lupins. The application of the GFSA framework enabled the evaluation of potential changes in food safety hazards from this transition and the establishment of appropriate control measures. In addition, GFSA users can employ the results to support decision-making process. Our case study showed that implementing GFSA can be challenging for smallholder or individual farmers and may need coordinated action. Finally, effective and transparent communication is critical for managing food safety along the food supply chain, including when changes are implemented in primary production.</div></div>","PeriodicalId":15903,"journal":{"name":"Journal of food protection","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142381052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Factors affecting the adhesion of flour particles to stainless-steel surfaces and vacuum dry-cleaning.","authors":"Ian M Klug, Bradley P Marks, Teresa M Bergholz, Sanghyup Jeong","doi":"10.1016/j.jfp.2024.100372","DOIUrl":"https://doi.org/10.1016/j.jfp.2024.100372","url":null,"abstract":"<p><p>Recent outbreaks and recalls linked to flour-based products have highlighted the need for improved cleaning methods in low-moisture environments. The factors affecting adhesion forces of flour particles, and the vacuum cleaning methodologies to overcome these forces, need to be better understood. The objectives of this study were to: (1) Measure electrostatic charge build-up in flour under different environmental conditions (20, 40, 60% relative humidity at room temperature), (2) quantify how powder size (US standard No. 60 - 80 or 80 - 100 mesh), electrostatic charge (charged and uncharged), and relative humidity impact the force required to remove the powder from an electropolished 304 stainless steel coupon (8 × 8 × 0.2 cm), and (3) determine the most effective vacuum nozzle angle (0, 45, 90° relative to the surface) for cleaning. Chargeability (nC) of flour samples was assessed using Faraday cup electrometry, while the surface adhesion force of the flour particles was measured using a custom-built impact tester. The surface cleanliness after vacuum treatments was assessed using ATP (adenosine triphosphate) swabs and a luminometer. Charged flour samples at 20% relative humidity (RH) exhibited a significantly higher charge compared to those at 40 and 60% RH. Within the 60 - 80 mesh range, charged flour showed higher adhesion rates than uncharged samples at both 20 and 40% RH. However, in the 80 - 100 mesh range, charged flour did not show a significant difference in adhesion when compared to uncharged samples at any RH level. Additionally, at 60% RH, surface residues measured by ATP were significantly lower for vacuum angle 90° than for 0° across both 60 - 80 mesh and 80 - 100 mesh size ranges of wheat flour. The vacuum cleaning treatment proved capable of overcoming the increase in adhesion from triboelectric forces, however trace flour residues were still detected on stainless steel surfaces post vacuuming, indicating that vacuuming alone may be insufficient.</p>","PeriodicalId":15903,"journal":{"name":"Journal of food protection","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142381051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Escherichia coli Survival on Dry Bulb Onions Treated with Crop Protection Sprays Prepared using Contaminated Water in the Treasure Valley Growing Region.","authors":"Jason Racine, Alexandra Nerney, Samantha Kilgore, Tim Waters, Faith Critzer, Linda J Harris, Stuart Reitz, Joy Waite-Cusic","doi":"10.1016/j.jfp.2024.100373","DOIUrl":"https://doi.org/10.1016/j.jfp.2024.100373","url":null,"abstract":"<p><p>Contaminated agricultural water has been implicated in produce-associated outbreaks, including dry bulb onions (Allium cepa). This study was designed to quantify risks associated with t contaminated water used to prepare crop protection sprays applied immediately before the onset of field curing of dry bulb onions. Laboratory experiments determining behavior of Salmonella and Escherichia coli in crop protection chemical solutions were performed to guide selection for field use. Field trials were conducted (2022, 2023) in eastern Oregon (Treasure Valley) using two onion cultivars ('Red Wing' and 'Cometa') inoculated with a rifampicin-resistant E. coli cocktail (3-4 log CFU/100 mL) suspended in fungicide solution or clay suspension, and applied with a backpack sprayer at the end of the growing season. Onions were sampled through the next 4 weeks of field curing and after 1 and 4-5 mos of postharvest storage. In 2022, onions were initially contaminated at a maximum cell density of 48 MPN/onion (Geometric mean (GM): 3.7 MPN/onion). At the end of curing, a single onion (out of 320) tested positive at 2 MPN/onion. In 2022, E. coli was not detected during postharvest storage (n = 160). In 2023, the application of contaminated sprays resulted in a maximum contamination of 275 MPN/onion (GM: 8.6 MPN/onion). At the end of the 2023 curing period, three out of 320 onions (0.9%) had detectable levels of E. coli (1-2 MPN/onion). Three 'Cometa' onions from the same plot that were treated with fungicide were positive for E. coli after 5 months of postharvest storage (2, 11, and 83 MPN/onion). These field trials indicate field curing conditions in the Treasure Valley help mitigate risks associated with contaminated water used for applying crop protection sprays. E. coli was detected on a small percentage of onions at low cell density after curing. The single onion with elevated E. coli populations after postharvest storage had internal damage characteristic of bacterial rot.</p>","PeriodicalId":15903,"journal":{"name":"Journal of food protection","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142381050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Profiling the Enterobacterales Community Isolated from Retail Foods in England","authors":"","doi":"10.1016/j.jfp.2024.100369","DOIUrl":"10.1016/j.jfp.2024.100369","url":null,"abstract":"<div><div><em>Enterobacterales</em> include foodborne pathogens of importance to public health and are often targeted in food surveillance programs as both safety and hygiene indicators. Furthermore, <em>Enterobacterales</em> are important in the context of antimicrobial resistance dissemination, also impacting infection treatment efficacy. In this study, the prevalence and characteristics of <em>Enterobacterales</em> in UK retail foods were examined. From 110 retail food samples, 253 <em>Enterobacterales</em> were recovered, with 16S rRNA sequencing revealing a diverse species community, including enteropathogens; the most common were <em>Proteus mirabilis</em> and <em>Escherichia coli</em> (18% each). Antimicrobial resistance was common, with 160/253 (63%) isolates being resistant to at least 1 antimicrobial. Resistance to all tested antimicrobials was observed. Thirteen percent of isolates were multidrug resistant, including 2 isolates each resistant to 8 or 9 of 9 antimicrobials tested. <em>Klebsiella</em> isolates possessed relatively higher levels of antimicrobial resistance to other species. <em>Hafnia</em>, <em>Kluyvera</em>, and <em>Proteus</em> isolates produced significantly higher biofilm biomass than <em>Klebsiella</em> (<em>p</em> = 0.038, 0.028, and 0.042, respectively) or <em>Escherichia</em> (<em>p =</em> 0.001, 0.008, and 0.001, respectively). Simultaneous curli fimbriae and cellulose production was noted in 7% of isolates at 37 °C, but not at 15 °C. This research demonstrates a high diversity of <em>Enterobacterales</em> within UK retail foods, alongside notable antimicrobial resistance phenotypes in enteropathogenic species, highlighting the need for effective surveillance and interventions.</div></div>","PeriodicalId":15903,"journal":{"name":"Journal of food protection","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142375556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extended-spectrum ß-lactamase (ESBL)- and Carbapenemase-producing Enterobacterales Isolated from Fresh Herbs and Salads at Retail Level in Switzerland","authors":"","doi":"10.1016/j.jfp.2024.100368","DOIUrl":"10.1016/j.jfp.2024.100368","url":null,"abstract":"<div><div>Fresh produce is usually consumed raw or minimally processed, making it a potential vehicle for the transmission of antimicrobial-resistant (AMR) microorganisms to humans. The objective of the study was to assess the occurrence of extended-spectrum ß-lactamase (ESBL)- and carbapenemase-producing Enterobacterales (ESBL-E and CPE), respectively, in 118 fresh herbs and 101 bagged salads collected at retail level in Switzerland and to characterize the isolates’ phenotypic and genotypic properties using culture-based methods and whole genome sequencing (WGS).</div><div>Of the fresh herbs, 6/118 contained ESBL-E and 7/118 yielded CPE. Of the salads, 13/101 contained ESBL-E and 1/101 CPE. Antimicrobial susceptibility testing (AST) identified 9/29 isolates as multidrug-resistant (MDR).</div><div>ESBL-E were <em>Escherichia coli</em> (<em>n</em> = 6), <em>Klebsiella pneumoniae</em> (<em>n</em> = 4) <em>Enterobacter chuandaensis</em> (<em>n</em> = 1), and <em>Kluyvera</em> spp. (<em>n</em> = 1) carrying ß-lactamase (<em>bla</em>) genes belonging to the cefotaximase-München (<em>bla</em>_CTX-M)-groups, <em>Proteus</em> spp. (<em>n</em> = 1) containing Hôpital-Universitaire-de-Genève-<em>bla</em> (<em>bla</em>_hugA), <em>Raoultella ornithinolytica</em> (<em>n</em> = 1) carrying sulfhydryl reagent variable <em>bla (bla</em>_SHV), and <em>Serratia fonticola</em> (<em>n</em> = 7) carrying <em>S. fonticula bla</em> (<em>bla</em>_FONA) genes. CPE were <em>Enterobacter asburiae</em> (<em>n</em> = 1) <em>E. cloacae</em> (<em>n</em> = 6) and <em>E. vonholyi</em> (<em>n</em> = 1) carrying imipenemase <em>bla</em> (<em>bla</em>_IMI) genes.</div><div>Several <em>K. pneumoniae</em> sequence types (STs) were identified (ST967, ST628, ST219, and ST1823), which have been linked to human disease and nosocomial outbreaks. They carried <em>bla</em>_CTX-M-15 on plasmids detected globally in environmental and clinical samples. <em>E. coli</em> (ST10, ST48, ST609, ST2040, ST6215 and ST3580) and enterotoxigenic <em>E. coli</em> (ETEC) ST2040 carrying <em>bla</em>_CTX-M-15 were found. <em>E. cloacae</em> (ST820 and ST1516) with <em>bla</em>_IMI-1 have been found previously in clinical settings and community outbreaks.</div><div>The occurrence and consumption of fresh produce containing MDR ESBL-E and CPE pose substantial public health risks and raise significant food safety concerns.</div></div>","PeriodicalId":15903,"journal":{"name":"Journal of food protection","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142375555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prevalence, Characteristics, and Selection of Bacillus cereus Subgroups from Dairy Products for Challenge Testing and Predictive Model Development","authors":"","doi":"10.1016/j.jfp.2024.100367","DOIUrl":"10.1016/j.jfp.2024.100367","url":null,"abstract":"<div><div>Prevalence, toxin gene profiles, lactose fermentation, and growth responses of <em>B. cereus sensu lato</em> subgroups in various dairy and dairy alternative products and ingredients were studied to identify relevant isolates for challenge testing and model development to predict and manage growth responses. Out of 71 examined products or ingredients, 51 <em>B. cereus s.l.</em> isolates were obtained from 35 positive samples (49% prevalence). These 51 isolates along with 18 additional dairy isolates and 12 <em>B. cereus s.l.</em> reference strains were identified using MALDI-TOF. The 81 isolates were further characterized by <em>panC</em> sequencing, testing for cold shock and toxin genes (<em>cspA</em>; <em>hbl</em>, <em>nhe, CytK</em> and <em>ces</em>), lactose fermentation, and study of growth rates (<em>µ_max</em>) under various conditions (45 °C, 10 °C, 6% NaCl, pH 5.1), resulting in 298 <em>µ_max</em>-values. These conditions were selected to differentiate mesophilic and psychrotolerant strains and to identify tolerant isolates. Dairy powders (83%), pasteurized upconcentrated cheese whey (43%), and cheeses (42%) had the highest prevalences of <em>B. cereus s.l.</em> and the highest concentrations in positive samples (5–100 CFU/g or ml). The <em>panC</em> groups II, III, IV, VI, and VIII were detected among the dairy isolates, with 97% harboring one or more toxin genes. Lactose fermentation was observed in 42% of isolates, with lactose-fermenting <em>B. cereus s.l.</em> isolates of <em>panC</em> groups III and IV dominant in dairy powders. Growth rates of <em>B. cereus s.l.</em> varied considerably, among and within <em>panC</em> groups of the dairy isolates. Based on the highest growth rates at 45 °C, 10 °C, 6% NaCl, pH 5.1, <em>panC</em> group membership, toxin genes profiles, and lactose fermentation ability, two cocktails of “mesophilic” or “psychrotolerant” isolates were selected. These strain cocktails can be used in future challenge testing and predictive food microbiology studies to evaluate and manage the growth of <em>B. cereus s.l.</em> in dairy products and ingredients.</div></div>","PeriodicalId":15903,"journal":{"name":"Journal of food protection","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142365493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}