Food Inspection Service Research Articles

Thermal Inactivation of Cells of Salmonella spp. in Pot Pies Prepared With a Beef, Chicken, or Meat Alternative Filling, With and Without Gravy, During Cooking in a Convection Oven

Cooking parameters elaborated in the U.S. Department of Agriculture’s Food Safety and Inspection Service Cooking Guideline for Meat and Poultry Products (Appendix A) were evaluated for inactivation of Salmonella spp. in pot pies. To prepare dough for pot pies, flour, butter, sugar, salt, and water were mixed, portioned into balls (65 or 85 g each), flattened (ca. 13 or 15 cm diameter, ca. 0.5 cm thick), and hand-pressed into pans (ca. 19.4 cm diameter). Next, a 100-g portion of beef, chicken, or a meat alternative, with or without added gravy (55 g of protein and 45 g of gravy), was inoculated with a cocktail of Salmonella spp. (ca. 6.5 or 7.9 log CFU/g of filling) and distributed onto the pie crust. After covering with a 65-g sheet of dough, pies were heat sealed in nylon polyethylene bags and stored at −20 °C for up to 72 h. Frozen pot pies containing a beef or meat alternative filling were cooked in a convection oven to an internal temperature of 57.8 °C (136°F) instantaneous, 62.8 °C (145°F) and held for 4 min, 67.2 °C (153°F) and held for 34 sec, or 71.1 °C (160°F) instantaneous; whereas chicken pot pies were cooked to an internal temperature of 57.8 °C (136°F) instantaneous, 62.8 °C (145°F) and held for 13 min, 67.2 °C (153°F) and held for 96 sec, or 73.9 °C (165°F) instantaneous. Cells of Salmonella spp. were recovered from uncooked or cooked pot pies by stomaching each pie in peptone water and enumerating pathogen levels via direct plating. Cooking delivered Salmonella spp. reductions of ca. 3.6 to ≥6.3 log CFU/g of pot pie. With few exceptions, when pathogen levels decreased to below detection by direct plating (0.5 log CFU/g of pot pie), cells of Salmonella were not recovered by enrichment. In addition, there were minimal differences in the aw and moisture content of the protein filling before and after cooking, suggesting that enclosing the meat, poultry, or meat alternative filling within a dough wrapping maintains moisture in the filling during the cooking process.

Trends in Salmonella Infantis human illness incidence and chicken carcass prevalence in the United States; 1996-2019.

The incidence of human illness due to Salmonella Infantis reported to Foodborne Diseases Active Surveillance Network and the prevalence of Infantis on chicken carcasses reported by the United States Department of Agriculture Food Safety and Inspection Service have increased significantly in the past decade. However, the trends do not appear coincident, as would be expected if the increased prevalence in chicken led to the increase in the incidence of human illness. Salmonella Infantis incidence and prevalence trends are analyzed using penalized B-spline methods for generalized additive regression models. The association between the two time series is analyzed using time-lagged rank-order cross-correlation. Geographic variations in reported incidence and trends are also explored. The increase in human incidence of Salmonella Infantis began circa 2011. The increase in chicken carcass prevalence began circa 2015. A 4-year lag on chicken carcass prevalence maximizes the rank-order cross-correlation with the incidence of illness. While chicken consumption undoubtedly contributes to the incidence of human illness due to Salmonella Infantis, the initial increase in reported illness was likely due to one or more other transmission pathways. Other potential transmission pathways include non-chicken foodborne, waterborne, person-to-person, animal contact, and environmental.

Inactivation of Listeria monocytogenes and Salmonella spp. During Cooking of Country Ham and Fate of L. monocytogenes and Staphylococcus aureus During Storage of Country Ham Slices

Thermal inactivation studies were undertaken on Listeria monocytogenes and Salmonella spp. inoculated on the surface of country ham. Hams (average = ca. 3.4 ± 0.5 kg each; average = ca. ≥18% shrinkage) were used as provided by the processor (i.e., “salted hams”), desalted in tap water (i.e., “desalted hams”), or dried for an additional period (i.e., “extra-dried hams”). Hams were surface inoculated (ca. 9.5 log CFU/ham) with a multistrain cocktail of L. monocytogenes or Salmonella spp. and cooked within a bag ina circulating water bath to an internal temperature of 130°F (54.4°C) instantaneous, 145°F (62.8°C) and held for 4 min, 153°F (67.2°C) and held for 34 s, or 160°F (71.1°C) instantaneous. Regardless of ham type, all four time and temperature combinations tested herein delivered a ≥6.7-log reduction of cells of L. monocytogenes or Salmonella spp. Differences in product pH, moisture content, or aw did not have an appreciable impact on the thermal inactivation of L. monocytogenes or Salmonella spp. on country ham. In addition, shelf-life studies were undertaken using slices of “salted” country ham that were surface inoculated (ca. 5.5 log CFU/slice) with a multistrain cocktail of L. monocytogenes or Staphylococcus aureus and then stored at 20°C. Levels of S. aureus increased by ca. ≤1.4 log CFU/slice during storage for 90 days, whereas levels of L. monocytogenes remained relatively unchanged (≤0.2 log CFU/slice increase). Our data validated that cooking parameters elaborated in the U.S. Department of Agriculture’s Food Safety and Inspection Service Cooking Guideline for Meat and Poultry Products (Revised Appendix A) are sufficient to deliver significant reductions (ca. ≥6.8 log CFU/ham) in levels of L.monocytogenes and Salmonella spp. on country ham. In addition, in the event of postprocessing contamination, country ham may support the outgrowth of S. aureus or survival of L. monocytogenes during storage at 20°C for 90 days.

Consumer Perception of Food Fraud in Serbia and Montenegro.

The main objective of this study was to investigate how food fraud is perceived among consumers in Serbia and Montenegro. A total of 1264 consumers from the two countries participated in an online survey during the second half of 2022, using Google forms®. In the Serbian population, older or highly educated respondents are aware of different types of fraudulent activities such as substitution, mislabeling, concealment, and counterfeiting. Dilution is mostly recognized by women, the younger population, and students. Consumers believe that trust is the most important factor when purchasing food. The highest level of agreement regarding food fraud is that such activities may pose serious health risks to consumers, and that food inspection services are the most responsible actors in the food chain continuum. When it comes to purchasing food, open green markets are most trustworthy, followed by hypermarkets. Concerning the types of food, fish is most susceptible to fraud, followed by olive oil. This study builds upon existing knowledge of food consumers about food fraud in Europe.

A Comparative Study on Antimicrobial Resistance in Escherichia coli Isolated from Channel Catfish and Related Freshwater Fish Species

Antimicrobial resistance (AMR) trends in 114 generic Escherichia coli isolated from channel catfish and related fish species were investigated in this study. Of these, 45 isolates were from commercial-sized channel catfish harvested from fishponds in Alabama, while 69 isolates were from Siluriformes products, accessed from the U.S. Department of Agriculture Food Safety and Inspection Service’ (FSIS) National Antimicrobial Resistance Monitoring System (NARMS) program. Antibiotic susceptibility testing and whole genome sequencing were performed using the GenomeTrakr protocol. Upon analysis, the fishpond isolates showed resistance to ampicillin (44%), meropenem (7%) and azithromycin (4%). The FSIS NARMS isolates showed resistance to tetracycline (31.9%), chloramphenicol (20.3%), sulfisoxazole (17.4%), ampicillin (5.8%) and trimethoprim-sulfamethoxazole, nalidixic acid, amoxicillin-clavulanic acid, azithromycin and cefoxitin below 5% each. There was no correlation between genotypic and phenotypic resistance in the fishpond isolates, however, there was in NARMS isolates for folate pathway antagonists: Sulfisoxazole vs. sul1 and sul2 (p = 0.0042 and p < 0.0001, respectively) and trimethoprim-sulfamethoxazole vs. dfrA16 and sul1 (p = 0.0290 and p = 0.013, respectively). Furthermore, correlations were found for tetracyclines: Tetracycline vs. tet(A) and tet(B) (p < 0.0001 each), macrolides: Azithromycin vs. mph(E) and msr(E) (p = 0.0145 each), phenicols: Chloramphenicol vs. mdtM (p < 0.0001), quinolones: Nalidixic acid vs. gyrA_S83L=POINT (p = 0.0004), and β-lactams: Ampicillin vs. blaTEM-1 (p < 0.0001). Overall, we recorded differences in antimicrobial susceptibility testing profiles, phenotypic-genotypic concordance, and resistance to critically important antimicrobials, which may be a public health concern.

Response to Questions Posed by the Food Safety and Inspection Service: Enhancing Salmonella Control in Poultry Products

Response to Questions Posed by the Food Safety and Inspection Service: Enhancing Salmonella Control in Poultry Products

Evaluation of public submissions to the USDA for labeling of cell-cultured meat in the United States.

With the rapid advancement of cell-cultured meat processing technologies and regulations, commercialization of cell-cultured meat to market shelves requires the implementation of labeling that informs and protects consumers while ensuring economic competitiveness. In November 2022, the United States Food and Drug Administration (FDA) completed its first pre-market consultation of cell-cultured meat and did not question the safety of these products for human consumption. As of June 2023, commercialization of cell-cultured meat products has become a reality in the United States. To derive potential label terms and gain insight into how different stakeholders refer to these novel products, we analyzed 1,151 comments submitted to the 2021 U.S. Department of Agriculture's Food Safety and Inspection Services (USDA-FSIS) call on the labeling of cell-cultured meat and poultry. Our first aim was to systematically assess the nature of comments with regards to their length, cited references, and supplemental materials. In addition, we aimed to identify the most used terms to refer to these products through text analysis. We also asked how these analyses would vary by affiliation category and economic interest. Using the listed organizations for each comment, we first determined financial ties: 77 (7%) comments came from those with an economic interest, 12 (1%) of the comments did not have an identifiable economic interest, while for the remaining 1,062 (92%) comments economic interest could not be determined. We then grouped comments into affiliation categories. Cell-cultured meat companies and animal welfare non-profits had the highest median word count, whereas comments from the unknown affiliation category had the lowest. We found across all comments the predominantly mentioned potential label terms, in descending order, to be cultured meat, lab-grown meat, cultivated meat, cell-cultured meat, clean meat, and cell-based meat. While all label terms were discussed throughout overall submissions, percentages of comments mentioning each term differed between affiliation categories. Our findings suggest differences in how affiliation categories are discussing cell-cultured meat products for the US market. As a next step, the perception and acceptance of these terms must be evaluated to identify the optimal label term regarding the information and protection provided to consumers while ensuring economic competitiveness.

Development and Verification of a Poultry Management Tool to Quantify Salmonella from Live to Final Product Utilizing RT-PCR.

The United States Department of Agriculture Food Safety and Inspection Service (USDA FSIS) does not maintain a zero-tolerance policy for Salmonella in poultry and poultry products, despite being a known food safety hazard throughout the poultry industry. In 2016, USDA FSIS established performance standards for a 52-week moving window with the maximum acceptable percent positive for comminuted turkey (325 g sample) at 13.5% (7 of 52 samples). Based upon FSIS verification sampling results from one 52-week moving window, the Salmonella prevalence for each poultry establishment in category 1 (below limit), 2 (meeting limit), or 3 (exceeding limit) are published for public viewing. Moreover, many poultry producers continue to have post-intervention samples test positive. Therefore, the use of quantification would be more valuable to determine the efficacy of process control interventions, corrective actions, and final product Log CFU/g of Salmonella to make rapid, within shift, food safety decisions. Therefore, the objectives of these studies are to develop, verify, and validate a rapid and reliable quantification method utilizing RT-PCR to enumerate Salmonella in the poultry industry from flock to final product and to utilize the method in an application study. BAX® System SalQuant® is an application of the BAX® System Real-Time PCR Assay for Salmonella to enumerate low levels of Salmonella with shortened enrichment times. Curve development encompassed inoculating poultry matrix samples at four levels with an ATCC strain of Salmonella, with three biological replicates per inoculation level, and five technical replicates being run on the BAX® System for various timepoints, gathering the data, and creating a linear-fit equation. A linear-fit equation was provided for each timepoint. The ideal timepoint, based on the statistical parameters surrounding the equation (R2 &gt; 0.80, Log RMSE &lt; 0.60, and enumerable range 0.00 to 4.00 Log CFU/mL (g)) that most accurately estimate Salmonella compared to most probable number (MPN), was chosen to be utilized for further studies.

How do consumers perceive food safety risks? – Results from a multi-country survey

An online survey was distributed to consumers in nine countries in order to investigate their perceptions related to causers of food safety risks, types of food associated with food-borne illnesses and the role of actors in the food supply chain. A total of 2723 respondents have participated in the survey. Results indicated that food hygiene has been recognized as the most important issue associated with food safety risks. Consumers considered meat and meat products as well as egg and egg-based products, as types of food that pose the highest risks to consumer's health. Food processors and food inspection services play the most significant role in food supply chains. Results further revealed that country of origin has the highest influence on consumer perception, opposed to gender with the least influence. Overall, results obtained in this study confirmed the role of food hygiene as the predominant factor in ensuring food safety in the mind of consumers and that animal-originated food has been perceived as the type of food holding higher health risk opposed to food of plant origin. At the same time, these results challenge the trust in food processors and food inspection services.

Assessing the effectiveness of performance standards for Salmonella contamination of chicken parts

The United States Department of Agriculture's Food Safety and Inspection Service implemented Salmonella performance standards for establishments producing chicken parts in 2016. The standards were chosen based on the assumption that a 30 % reduction in the occurrence of Salmonella-contaminated chicken parts samples (i.e., legs, breasts or wings) would result following implementation of the performance standard program. The derivation of the performance standards was based on data collected prior to the implementation of the standards and in the intervening years, so overall changes in the Salmonella contamination of this product can be assessed. This study presents a historical review of changes in Salmonella contamination on chicken parts as these changes relate to the performance standard. The analysis demonstrates that the reduction in Salmonella contaminated chicken parts samples was more than 75 %, so the FSIS risk assessment significantly underestimated the actual reduction in Salmonella contamination. An analysis of chicken parts samples collected at retail demonstrates reductions of a similar magnitude. Changes in the characteristics of Salmonella contamination that are potentially relevant to the occurrence or severity of human illness, such as seasonal changes in contamination, the composition of serotypes and changes in antimicrobial resistance, are also assessed. Small but significant seasonal increases in contamination were observed, with the peaks occurring in late winter rather than the more traditional late summer peak. Rapid changes in both the five most common serotypes and antimicrobial resistance patterns were also observed.

Predicting the Growth of Listeria monocytogenes in Cooked, Sliced Deli Turkey Breast as a Function of Clean-Label Antimicrobials, pH, Moisture, and Salt

The use of antimicrobials in formulated ready-to-eat meat and poultry products has been identified as a major strategy to control Listeria monocytogenes. The U.S. Department of Agriculture's Food Safety and Inspection Service recommends no more than 2 log of Listeria outgrowth over the stated shelf life if antimicrobials are used as a control measure for a product with postlethality environmental exposure. This study was designed to understand the efficacy of a clean-label antimicrobial agents against the growth of L. monocytogenes as affected by the product attributes. A response surface method-central composite design was used to investigate the effects of product pH, moisture, salt content, and a commercial "clean-label" antimicrobial agent on the growth of L. monocytogenes in a model turkey deli meat formulation. Thirty treatment combinations of pH (6.3, 6.5, and 6.7), moisture (72, 75, and 78%), salt (1.0, 1.5, and 2.0%), and antimicrobials (0.75, 1.375, and 2.0%), with six replicated center points and eight design star points were evaluated. Treatments were surface inoculated with a 3-log CFU/g target of a five-strain L. monocytogenes cocktail, vacuum packaged, and stored at 5°C for up to 16 weeks. Populations of L. monocytogenes were enumerated from triplicate samples every week until the stationary growth phase was reached. The enumeration data was fitted to a Baranyi and Roberts growth curve to calculate the lag time and maximum growth rate for each treatment. Linear least-squares regression of the lag time and growth rate against the full quadratic, including the second-order interaction terms, design matrix was performed. Both lag time and maximum growth rate were significantly affected (P < 0.01) by the antimicrobial concentration and product pH. Product moisture and salt content affected (P < 0.05) lag phase and maximum growth rate, respectively. The availability of a validated growth model assists meat scientists and processors with faster product development and commercialization.

Validation of the 3M™ Molecular Detection Assay 2 - STEC Gene Screen (stx) for the Detection of Shiga Toxin Gene (stx1 and/or stx2) in Additional Matrixes: AOAC Performance Tested MethodSM 071903.

BackgroundThe 3M™ Molecular Detection Assay 2 - STEC Gene Screen (stx) method is based on gene amplification by the use of real-time loop-mediated isothermal amplification when used with the 3M Molecular Detection System for the rapid and specific detection of Shiga toxin gene (stx1 and/or stx2) from Shiga toxin-producing enterohemorrhagic Escherichia coli (STEC) in enriched foods.ObjectiveThe 3M Molecular Detection Assay 2 - STEC Gene Screen (stx) method was evaluated as a Level 2 method modification to add new matrixes to the certified claim: 25 g fresh raw ground beef (approximately 75% lean), 375 g raw beef trim (approximately 75% lean), 375 g fresh raw ground pork (approximately 70% lean), 375 g fresh raw poultry parts, and 25 g sprouts.MethodsMatrix studies were conducted to assess the method’s performance compared to the US Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guidebook, 5C.00 for meat and poultry, and to the US Food and Drug Administration Bacteriological Analytical Manual, Ch. 4A for sprouts, using an unpaired study design.ResultsThe 3M Molecular Detection Assay 2 - STEC Gene Screen (stx) method demonstrated no significant differences between presumptive and confirmed results or between candidate and reference method results for any of the matrices tested.Conclusion and HighlightsThe data collected in these studies demonstrate that the 3M Molecular Detection Assay 2 - STEC Gene Screen (stx) is a reliable method for the rapid and specific detection of STEC in fresh raw ground beef (approximately 75% lean), fresh raw beef trim (approximately 75% lean), fresh raw ground pork (approximately 70% lean), fresh raw poultry parts, and sprouts.

Validation of the 3M™ Molecular Detection Assay 2 - STEC Gene Screen (stx and eae) for the Detection of Shiga Toxin Gene (stx1 and/or stx2) and Intimin Gene (eae): AOAC Performance Tested MethodSM 071902.

BackgroundThe 3M™ Molecular Detection Assay 2 - STEC Gene Screen (stx and eae) method is based on gene amplification by the use of real-time loop-mediated isothermal amplification when used with the 3M Molecular Detection System for the rapid and specific detection of Shiga toxin gene (stx1 and/or stx2) and intimin gene (eae) from Shiga toxin-producing enterohemorrhagic Escherichia coli (STEC) in enriched foods.ObjectiveThe 3M Molecular Detection Assay 2 - STEC Gene Screen (stx and eae) method was evaluated as a Level 2 method modification to add new matrixes to the certified claim: 25 g fresh raw ground beef (approximately 75% lean), 375 g fresh raw ground pork (approximately 70% lean), 375 g fresh raw poultry parts, and 25 g sprouts.MethodsMatrix studies were conducted to assess the method’s performance compared to the U. S. Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guidebook, 5C.00 for meat and poultry, and to the U. S. Food and Drug Administration Bacteriological Analytical Manual, Ch. 4A for sprouts, using an unpaired study design.ResultsThe 3M Molecular Detection Assay 2 - STEC Gene Screen (stx and eae) method demonstrated no significant differences between presumptive and confirmed results or between candidate and reference method results for any of the matrixes tested.Conclusion and HighlightsThe data collected in these studies demonstrate that the 3M Molecular Detection Assay 2 - STEC Gene Screen (stx and eae) is a reliable method for the rapid and specific detection of STEC in fresh raw ground beef (approximately 75% lean), fresh raw ground pork (approximately 70% lean), fresh raw poultry parts, and sprouts.

Comparison of Statistical Methods for Identifying Risk Factors for Salmonella Contamination of Whole Chicken Carcasses

The complexity of the food system makes analyzing microbiological data from food studies challenging because many of the assumptions (e.g., linear relationship between independent and dependent variable and independence of observations) associated with common analytical approaches (e.g., analysis of variance) are violated. Repeated sampling within an establishment introduces longitudinal correlation that must be accounted for during analyses. In this study, statistical methods for clustered or correlated data were used to determine how correlation impacts conclusions and to compare how assumptions associated with statistical methods impact the appropriateness of these methods within the context of food safety. Risk factor analyses for Salmonella contamination of whole chicken carcasses were conducted as a case study with regulatory data collected by the U.S. Department of Agriculture Food Safety and Inspection Service between May 2015 and December 2019 from 203 regulated establishments. Three models, generalized estimating equation, random effects, and logistic, were fit to Salmonella presence or absence data with establishment demographics and inspection history included as potential covariates. Beta parameter estimates and their standard errors and odds ratios and their 95% confidence intervals were compared across models. Conclusions drawn from the three models differed with respect to geographic region, whether the chicken establishment also slaughters turkeys, and establishment noncompliance with 9 CFR §417.4 (hazard analysis critical control point system validation, verification, and reassessment) in the 84 days leading up to sample collection. The results of this study reveal the need to consider clustering and correlation when analyzing food microbiological data, provide context for selecting a statistical method, and suggest that generalized estimating equation and random effects models are preferrable over logistic regression when analyzing correlated food data. These results support a renewed focus on statistical methodology in food safety.

Risk Factors for Salmonella Contamination of Whole Chicken Carcasses following Changes in U.S. Regulatory Oversight

Salmonella is a common cause of foodborne illness in the United States and often is linked to chicken products. Salmonella contamination has been associated with meat processing facility characteristics, such as the number of employees (i.e., hazard analysis critical control point [HACCP]-based definition of size). The risk factors for Salmonella contamination in U.S. poultry have not been evaluated since implementation of the New Poultry Inspection System (NPIS) in 2014. The goal of this study was to determine whether risk factors for Salmonella contamination changed after implementation of the NPIS. Presence or absence of Salmonella in whole chicken carcasses was modeled using microbiological testing data collected from 203 poultry processing establishments by the U.S. Department of Agriculture Food Safety and Inspection Service between May 2015 and December 2019. A model was fit using generalized estimating equations for weekly presence or absence of Salmonella, and production volume, geographic location, and season were included as potential covariates among other establishment demographics. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated from the marginal model. Of the 40,497 analyzable samples, 1,725 (4.26%) were positive for Salmonella. Odds of contamination was lower among establishments slaughtering ≥10,000,000 birds per year (OR = 0.466; 95% CI, [0.307, 0.710]) and establishments producing ready-to-eat finished products (OR = 0.498; 95% CI, [0.298, 0.833]) and higher among establishments historically (previous 84 days) noncompliant with HACCP regulations (OR = 1.249; 95% CI, [1.071, 1.456]). Contamination also significantly varied by season and geographic region, with higher odds of contamination during summer and outside the MidEast Central region. These results support continuation of targeted food safety policies and initiatives promoting pathogen reduction by establishments with smaller volumes and those noncompliant with HACCP regulations.

Decreased Incidence of Infections Caused by Pathogens Transmitted Commonly Through Food During the COVID-19 Pandemic - Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2017-2020.

Foodborne illnesses are a substantial and largely preventable public health problem; before 2020 the incidence of most infections transmitted commonly through food had not declined for many years. To evaluate progress toward prevention of foodborne illnesses in the United States, the Foodborne Diseases Active Surveillance Network (FoodNet) of CDC's Emerging Infections Program monitors the incidence of laboratory-diagnosed infections caused by eight pathogens transmitted commonly through food reported by 10 U.S. sites.* FoodNet is a collaboration among CDC, 10 state health departments, the U.S. Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS), and the Food and Drug Administration. This report summarizes preliminary 2020 data and describes changes in incidence with those during 2017-2019. During 2020, observed incidences of infections caused by enteric pathogens decreased 26% compared with 2017-2019; infections associated with international travel decreased markedly. The extent to which these reductions reflect actual decreases in illness or decreases in case detection is unknown. On March 13, 2020, the United States declared a national emergency in response to the COVID-19 pandemic. After the declaration, state and local officials implemented stay-at-home orders, restaurant closures, school and child care center closures, and other public health interventions to slow the spread of SARS-CoV-2, the virus that causes COVID-19 (1). Federal travel restrictions were declared (1). These widespread interventions as well as other changes to daily life and hygiene behaviors, including increased handwashing, have likely changed exposures to foodborne pathogens. Other factors, such as changes in health care delivery, health care-seeking behaviors, and laboratory testing practices, might have decreased the detection of enteric infections. As the pandemic continues, surveillance of illness combined with data from other sources might help to elucidate the factors that led to the large changes in 2020; this understanding could lead to improved strategies to prevent illness. To reduce the incidence of these infections concerted efforts are needed, from farm to processing plant to restaurants and homes. Consumers can reduce their risk of foodborne illness by following safe food-handling and preparation recommendations.

Comparative Evaluation of the SMARTCHECK® Listeria monocytogenes Detection Kit for GENECHECKER® UF-300 Real-Time PCR System for Select Foods: AOAC Performance Tested MethodSM 042101.

The candidate method, SMARTCHEK® Listeria monocytogenes Detection Kit, is designed for rapid detection of L. monocytogenes in select food matrixes, for use in conjunction with the Genesystems Rapi:chipTM and GENECHECKER®UF-300 real-time PCR system. The independent laboratory evaluation consisted of an inclusivity and exclusivity study, product consistency study, robustness study, stability study, and a matrix study. The paired matrix study tested stainless-steel environmental sponges, uncured ready-to-eat deli turkey, ready-to-eat deli ham, cooked shrimp, and fresh bagged spinach. The robustness study evaluated the method by changing three parameters. The accelerated stability and product consistency study was conducted at 8, 16, 24, 32, and 40 days. The candidate method was compared to the US Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guidebook, 8.11 Isolation and Identification of Listeria monocytogenes from Red Meat, Poultry, Ready-to-Eat Siluriformes (Fish) and Egg Products, and Environmental Samples and to the US Food and Drug Administration Bacteriological Analytical Manual Chapter 10: Detection of Listeria monocytogenes in foods and Environmental Samples, and Enumeration of Listeria monocytogenes in Foods following a paired study design. All 50 L. monocytogenes isolates were detected in all three broths tested for inclusivity, while all 37 non-L. monocytogenes isolates were correctly excluded. In the matrix study, the candidate method showed no significant differences between confirmed candidate method results and reference method results for all food matrixes evaluated. The candidate method is an effective method for the qualitative detection of L. monocytogenes in select food matrixes. The SMARTCHECK Listeria monocytogenes Detection Kit assay allows for fast, reliable detection of L. monocytogenes with results obtained in approximately 35 min after 18-48 h pre-enrichment, depending on the matrix.

Comparative Evaluation of the SMARTCHEK Salmonella Species Detection Kit for GENECHECKER UF-300 Real-Time PCR System with Rapi:chipTM and Rapi:DirectTM Lysis Buffer for Select Foods: AOAC Performance Tested MethodSM 032101

The candidate method, SMARTCHEK Salmonella spp. Detection Kit assay is designed for rapid detection of Salmonella spp. in select food matrixes, for use in conjunction with the Genesystems Rapi:chipTM and GENECHECKER UF-300 real-time PCR system. The independent laboratory evaluation consisted of an inclusivity and exclusivity study, product consistency study, robustness study, stability study, and a matrix study. The paired matrix study tested romaine lettuce, peanut butter, liquid whole egg, chicken carcass rinsate, and raw chicken. The robustness study evaluated the method by changing three method parameters. The accelerated stability and product consistency study was conducted at 8, 16, 24, 32, and 40 days. The candidate method was compared to the U.S. Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guidebook 4.10 Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg, and Siluriformes (Fish) Products and Carcass and Environmental Sponges and to the U.S. Food and Drug Administration Bacteriological Analytical Manual, Chapter 5: Salmonella following a paired study design. All 108 Salmonella isolates were detected in all three broths tested for inclusivity, while all 35 non-Salmonella isolates were correctly excluded. In the matrix study, the candidate method showed no significant differences between confirmed candidate method results and reference method results for all food matrixes evaluated. The candidate method is an effective method for the qualitative detection of Salmonella spp. in select food matrixes. The SMARTCHEK Salmonella spp. Detection Kit assay allows for fast, reliable detection of Salmonella spp. with results obtained after 24 h of incubation and a PCR run time of only 35 min.

Fate of &lt;i&gt;Escherichia coli&lt;/i&gt; O157:H7, &lt;i&gt;Salmonella&lt;/i&gt; spp., and &lt;i&gt;Listeria monocytogenes&lt;/i&gt; During Curing and Drying of Beef Bresaola

Manufacturing dry-cured meat products without a thermal lethality step is a growing trend for charcuterie companies in the United States. The United States Department of Agriculture Food Safety and Inspection Service requires that hazards for ready-to-eat meat products be addressed with a scientifically valid Hazard Analysis Critical Control Point system. Because little validation literature exists for these products, an experiment was designed to investigate the safety of beef bresaola. The objective of this study was to determine the reduction of Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes during curing and drying of bresaola.Prior to curing, whole beef semitendinosus muscle was inoculated with a mixed culture containing 3 strains each of E. coli O157:H7, Salmonella spp., and L. monocytogenes, allowed to air dry (30 min at 23°C), sprayed with a 2.5% Beefxide antimicrobial treatment (Birko Corp., Henderson, CO), and allowed to sit overnight in a walk-in cooler (2°C–4°C). Cure (NaNO3and NaNO2) and salt were applied to the beef surface 24 h after the antimicrobial treatment, and the beef was cured for 28 d (2°C–4°C). Following curing, a proprietary spice mixture was surface coated, and each piece was stuffed into beef casings (115–130 mm). The stuffed bresaola pieces were hung and allowed to dry for 35 d to a target water activity < 0.92 (13.63°C ± 2°C; relative humidity 68% ± 7%). Pathogen populations and water activity were analyzed on days 0, 1, and 2 and then weekly until day 65 of the study. Final reductions of 5.97, 5.98, and 5.44 log10 colony-forming units (CFU)/cm2 were achieved on day 65 for E. coli, Salmonella spp., and L. monocytogenes, respectively. During the entire curing and drying process, populations of each species never increased by more than 0.5 log10 CFU/cm2. The critical parameters used to cure and dry this product are sufficient to achieve the minimum 5 log10 CFU/cm2 reduction of each pathogen as required by the United States Department of Agriculture Food Safety and Inspection Service to validate process safety.

Prevalence and Genetic Analysis of Chromosomal mcr-3/7 in Aeromonas From U.S. Animal-Derived Samples.

The prevalence of mcr-positive bacteria in 5,169 domestic animal-derived samples collected by USDA Food Safety and Inspection Service between October 2018 and May 2019 was investigated. A procedure including enriched broth culture and real-time PCR targeting mcr-1 to mcr-8 were used for the screening. Fifteen positive isolates were identified, including one plasmid-borne mcr-1-positive Escherichia coli strain, EC2492 (reported elsewhere) and 14 mcr-3/7-positive strains from poultry (1), catfish (2), and chicken rinse (11) samples, resulting in an overall prevalence of mcr-positive bacteria 0.29% in all meat samples tested. Analysis of 16S rRNA and whole genome sequences revealed that all 14 strains belonged to Aeromonas. Data from phylogenetic analysis of seven housekeeping genes, including gyrB, rpoD, gyrA, recA, dnaJ, dnaX, and atpD, indicated that nine strains belonged to Aeromonas hydrophila and five strains belonged to Aeromonas jandaei. Antimicrobial tests showed that almost all mcr-positive strains exhibited high resistance to colistin with MICs ≥ 128mg/L, except for one A. jandaei strain, which showed a borderline resistance with a MIC of 2 mg/L. A segment containing two adjacent mcr-3 and mcr-3-like genes was found in two A. hydrophila and one A. jandaei strains and a variety of IS-like elements were found in the flanking regions of this segment. A mcr-3-related lipid A phosphoethanolamine transferase gene was present in all 14 Aeromonas strains, while an additional mcr-7-related lipid A phosphoethanolamine transferase gene was found in 5 A. jandaei strains only. In addition to mcr genes, other antimicrobial resistance genes, including blaOXA–12/OXA–724, aqu-2, tru-1, cepS, cphA, imiH, ceph-A3, ant(3″)-IIa, aac(3)-Via, and sul1 were observed in chromosomes of some Aeromonas strains. The relative high prevalence of chromosome-borne mcr-3/7 genes and the close proximity of various IS elements to these genes highlights the need for continued vigilance to reduce the mobility of these colistin-resistance genes among food animals.