Journal of food protection最新文献

With the emergence of clade 2.3.4.4b H5N1 highly pathogenic avian influenza virus (AIV) infection of dairy cattle and its subsequent detection in raw milk, coupled with recent AIV infections affecting dairy farm workers, experiments were conducted to affirm the safety of cooked ground beef related to AIV because such meat is often derived from cull dairy cows. Specifically, retail ground beef (percent lean:fat = ca. 80:20) was inoculated with a low pathogenic AIV (LPAIV) isolate to an initial level of 5.6 log₁₀ 50% egg infectious doses (EID₅₀)  per 300 g patty. The inoculated meat was pressed into patties (ca. 2.54 cm thick, ca. 300 g each) and then held at 4 °C for up to 60 min. In each of the two trials, two patties for each of the following three treatments were cooked on a commercial open-flame gas grill to internal instantaneous temperatures of 48.9 °C (120°F), 62.8 °C (145°F), or 71.1 °C (160°F), but without any dwell time. Cooking inoculated ground beef patties to 48.9 °C (ave. cooking time of ca. 15 min) resulted in a mean reduction of ≥2.5 ± 0.9 log₁₀ EID₅₀ per 300 g of ground beef as assessed via quantification of virus in embryonating chicken eggs (ECEs). Likewise, cooking patties on a gas grill to 62.8 °C (ave. cooking time of ca. 21 min) or to the USDA FSIS recommended minimum internal temperature for ground beef of 71.1 °C (ave. cooking time of ca. 24 min) resulted in a reduction to nondetectable levels from initial levels of ≥5.6 log₁₀ EID₅₀ per 300 g. These data establish that levels of infectious AIV are substantially reduced within inoculated ground beef patties (20% fat) using recommended cooking procedures.

In many jurisdictions, foodservice workers are required to obtain food handler certification via written examination before being able to work. This study investigated the effect of the readability, or the ease in which one can read and comprehend written text, of food handler exam questions on exam performance. It was hypothesized that the reduction in cognitive load by improving the readability of exam questions would lead to improved scores. Participants received training in personal hygiene and basic food safety and were tested on their knowledge using questions that were worded using the traditional phrasing and updated phrasing that has improved readability. The results indicate that improved readability had a significant difference in the personal hygiene section but not on the basic food safety section. These results are due, in part, to the types of cognitive load (intrinsic vs. extraneous) that are required to solve different types of problems.

The study determined the antimicrobial resistance (AMR) profiles of Listeria spp. (L. monocytogenes, L. innocua, and L. welshimeri) recovered from beef and beef products sold at retail outlets in Gauteng Province, South Africa. A total of 112 isolates of Listeria spp., including L. monocytogenes (37), L. innocua (65), and L. welshimeri (10), were recovered from beef and beef products collected from 48 retail outlets. Listeria spp. was recovered by direct selective plating following selective enrichment, and PCR was used to confirm and characterize recovered isolates. The disc diffusion method determined the resistance to 16 antimicrobial agents. All 112 isolates of Listeria spp. exhibited resistance to one or more antibiotics (P < 0.05). The prevalence of AMR in Listeria isolates was high for nalidixic acid (99.1%) and cefotaxime (80.4%) but low for gentamycin (2.7%), sulfamethoxazole-trimethoprim (3.6%), azithromycin (5.4%), and doxycycline (6.3%). Overall, for the three species of Listeria, the prevalence of resistance varied significantly only for streptomycin (P = 0.016) and tetracycline (P = 0.034). Multidrug-resistant isolates were detected in 75.7% (28/37), 61.5% (40/65), and 80% (8/10) isolates of L. monocytogenes, L. innocua, and L. welshimeri, respectively. The prevalence of AMR was significantly affected by the location and size of retail outlets, type of beef and beef products, and serogroups of L. monocytogenes. The high prevalence of AMR, particularly among the L. monocytogenes isolates, poses potential therapeutic implications for human consumers of contaminated beef products. There is, therefore, a need to regulate and enforce the use of antimicrobial agents in humans and animals in South Africa.

Bacillus thuringiensis-based commercial products as a biopesticide have been used for more than 60 years in agriculture. However, as one of the species in B. cereus group, B. thuringiensis has been considered as an emerging hazard with the potential to cause food toxico-infections. The present study aimed to evaluate the biofilm-forming ability of B. thuringiensis biopesticide strains and their attachment on spinach, compared to foodborne B. cereus strains. Biofilm formations of tested strains were found to be strain-specific and affected by the nutrient conditions more than the incubation time. Nutrient starvation conditions generally reduced the biofilm formation of tested B. thuringiensis and B. cereus strains, particularly B. thuringiensis ABTS-1857 strain was found as the nonbiofilm former in starvation conditions. It is worth mentioning that B. thuringiensis SA-11 strain showed stronger biofilm-forming ability with more air–liquid interface biofilm than the other two B. thuringiensis biopesticide strains, but no such higher attachment of B. thuringiensis SA-11 to spinach was observed. These results indicate that B. thuringiensis SA-11 strain can enter the food processing lines by the attachment on spinach leaves, and it has the potential to form biofilms throughout the processing lines or the production environment when sufficient nutrients are available. However, more biofilm tests of B. thuringiensis biopesticide strains in the vegetable production chain should be performed. The dry formulation of commercial B. thuringiensis biopesticides enhanced their adhesion on spinach leaves, whereas the strength of adhesion was not improved by the formulation. In addition, 1–2 log reductions of spores after the intensive washing of spinach leaves in the lab were detected. However, the log reduction due to the actual washing done by the food processing companies in large-volume washing baths or by consumers at home would be limited and less than this lab simulation.

Despite extensive Salmonella controls used at processing, 5.5% of salmonellosis cases are linked to turkey. This study had two objectives: (i) to summarize USDA-FSIS turkey Salmonella verification program data and (ii) to evaluate Salmonella through turkey production and processing of 22 flocks. In objective 1, USDA-FSIS data show the average Salmonella prevalence in ground turkey from 2016 to 2022 was 15.9%, and that the leading serovar changes frequently. For objective 2, bootsocks (n = 22) were collected on-farm right after load-out. At processing, prescald wingtips (n = 6 composites of 10/flock), prechill wingtips (n = 6 composites of 10/flock), mechanically separated turkey (MST; n = 6 bins/flock), and ground turkey (n = 6 bins/flock) were collected. Salmonella prevalence was determined by a commercial qPCR and culture confirmed. In 33.2% of PCR-positive samples, Salmonella was not confirmed by culture, highlighting a discrepancy between molecular and culture detection. On-farm, 8/22 flocks were Salmonella positive, compared to 21 flocks that were positive at one or more processing locations, including 18 flocks that were positive in at least one final product sample. A logistic regression showed higher Salmonella prevalence in prescald (53.8%) than in prechill (18.2%), MST (27.3%) or ground turkey (26.5%). CRISPR-SeroSeq analysis of 148 culture−positive samples detected 18 Salmonella serovars and showed 35.1% of samples contained multiple serovars. In 16 flocks, one or more serovars detected in final products were absent from any upstream samples. Two−thirds of final product samples containing serovar Typhimurium typed as a live-attenuated Typhimurium vaccine strain. Salmonella on-farm and at prescald did not reflect Salmonella observed in final product. These data underscore the complexity of serovar tracking in turkey production and highlight challenges to identify surveillance samples that accurately represent Salmonella in turkey products.

This study aimed to determine the bacteriological quality and presence of diarrheagenic Escherichia coli pathotypes (DEP) and nontuberculous mycobacteria (NTM) species in 85 packaged ice samples from 12 different states of central Mexico. Three samples had a pH of 9.8 and therefore fell outside of the acceptable range for pH. All samples were positive for aerobic-mesophilic bacteria, with limits ranging from 1 to 3.47 log CFU/mL. In total, 35, 11, and 3 ice samples were positive for total coliforms (TC), fecal coliforms (FC), and E. coli, respectively. In the samples, the TC concentration ranged from <1.1 to >23 MPN/100 mL and from <1.1 to 23 MPN/100 mL for FC and E. coli. In total, 38 (44.7%) ice samples were outside of Mexico's official guidelines. None of the 12 E. coli strains isolated from the three ice samples belonged to DEP. NTM were recovered from 20 ice samples and included M. neoaurum (n = 7), M. porcinum (n = 2), M. flavescens (n = 2), M. fortuitum (n = 1), M. abscessus (n = 1), M. senegalense (n = 1), M. conceptionense (n = 1), and M. sp. (n = 1). In the remaining four samples, two NTM were isolated simultaneously. Thus, we recommend that producers should evaluate the microbiological quality of purified water used as a raw material as well as that of the final product, the ice should be packed in thick bags to avoid stretching and tearing during transportation or storage to prevent environmental contamination of ice, personnel involved in the production, and handling of ice should be trained in relative hygiene matters and how ice-machines should be cleaned and disinfected and the implementation of hazard analysis and critical control points must be applied throughout the chain of production. Finally, regular inspection by the authorities is also of great importance. These recommendations can be applied in different countries with low microbiological quality packaged ice.

The 2021 FSIS Stabilization Guidelines for Meat and Poultry Products (Appendix B) Option 1.2 limits Phase 1 cooling from 48.8 to 26.7 °C in uncured meats to 1 h. However, this time restriction is impractical to achieve in large−diameter whole−muscle products. The objective of this study was to compare the inhibitory effect of commercial dry vinegars (DVs) and cultured sugar-vinegar blends (CSVs) on Clostridium perfringens and Bacillus cereus in uncured beef and poultry products during extended cooling. Treatments (beef: 72–73% moisture, pH 6.2–6.3, 0.85–0.95% NaCl; turkey: 76–77% moisture, pH 6.5–6.7, 1.3–1.6% NaCl) included Controls without antimicrobials, and four DV and four CSV, each tested at 0.75 and 1.25%. Batches were inoculated with 2.5-log C. perfringens or B. cereus spores, vacuum-packaged, and cooked to 73 °C. Packages were cooled from 48.8 to 27 °C (Phase 1) in 3, 4, or 5 h; Phase 2 (27–12.8 °C) and Phase 3 (12.8–4 °C) were standardized for 5-h cooling each. Pathogens were enumerated on selective agar in triplicate samples assayed at precook, postcook, and at the end of Phase 1, 2, and 3 cooling. Experiments were conducted twice. B. cereus did not grow (<0.5-log increase) in any treatment when Phase 1 cooling was extended to 5 h. C. perfringens grew rapidly (2.5 to >4.5 log) in Control treatments when Phase 1 cooling was extended to ≥3 h. All 1.25% DV ingredients limited C. perfringens growth to ≤1-log when Phase 1 cooling was extended to 3 h but supported a >1-log increase when Phase 1 cooling was extended to 5 h. All 1.25% CSV inhibited growth under 3-h Phase 1 cooling; 1.25% CSV-A and ≥0.75% CSV-D inhibited growth in turkey during 5-h Phase 1 cooling, but inhibition with 1.25% CSV-C was inconsistent in beef. This study revealed that formulating uncured meats with 1.25% DV or certain CSV can extend Phase 1 cooling to 3 h. Although all ingredients inhibited growth when used at 0.75% or greater compared to a control, greater variability of inhibition was observed among CSV than for DV.

The efficacy of a sanitizer in biofilm removal may be influenced by a combination of factors such as sanitizer exposure time and concentration, bacterial species, surface topography, and shear stresses. We employed an inline biofilm reactor to investigate the interactions of these variables on biofilm removal with chlorine. The CDC bioreactor was used to grow E. coli O157:H7 and L. monocytogenes biofilms as a single species or with Ralstonia insidiosa as a dual-species biofilm on stainless steel, PTFE, and EPDM coupons at shear stresses 0.368 and 2.462 N/m² for 48 hours. Coupons were retrieved from a CDC bioreactor and placed in an inline biofilm reactor and 100, 200, or 500 ppm of chlorine was supplied for 1- and 4 min. Bacterial populations in the biofilms were quantified pre- and posttreatment by plating on selective media. After chlorine treatment, reduction (Log CFU/cm²) in pathogen populations obtained from three replicates was analyzed for statistical significance. A 1-min chlorine treatment (500 ppm), on dual-species E. coli O157:H7 biofilms grown at high shear stress of 2.462 N/m² resulted in significant E. coli O157:H7 reductions on SS 316L (2.79 log CFU/cm²) and PTFE (1.76 log CFU/cm²). Similar trend was also observed for biofilm removal after a 4-min chlorine treatment. Single species E. coli O157:H7 biofilms exhibited higher resistance to chlorine when biofilms were developed at high shear stress. The effect of chlorine in L. monocytogenes removal from dual-species biofilms was dependent primarily on the shear stress at which they were formed rather than the surface topography of materials. Besides surface topography, shear stresses at which biofilms were formed also influenced the effect of sanitizer. The removal of E. coli O157:H7 biofilms from EPDM material may require critical interventions due to difficulty in removing this pathogen. The inline biofilm reactor is a novel tool to evaluate the efficacy of a sanitizer in bacterial biofilm removal.

The efficacy of three antimicrobials was evaluated against two severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) surrogates – bovine coronavirus (BCoV) and human coronavirus (HCoV) OC43 – on hard and soft nonporous materials. Three antimicrobials with three different active ingredients (chlorine, hydrogen peroxide, and quaternary ammonium compound + alcohol) were studied. Initially, a neutralization method was optimized for each antimicrobial. Then, we determined their efficacy against BCoV and HCoV OC43 in both suspension and on surfaces made with polyethylene terephthalate (PET) plastic and vinyl upholstery fabric. All tests were conducted under ambient environmental conditions with a soil load of 5% fetal bovine serum. After a 2-min exposure, all three antimicrobials achieved a >3.0 log₁₀ reduction in viral titers in suspension. All three also reduced virus infectivity on both surface materials below the detection limit (0.6 log₁₀ TCID₅₀/carrier). Treatments in which the reduction in virus titer was <3.0 log₁₀ were attributed to a decreased dynamic range on the carrier during drying prior to disinfection. The carrier data revealed that both surrogates were inactivated more rapidly (p <0.05) on vinyl or under conditions of high relative humidity. Three classes of antimicrobials were efficacious against both SARS-CoV-2 surrogate viruses, with BCoV demonstrating slightly less sensitivity compared to HCoV OC43. These findings also illustrate the importance of (1) optimizing the neutralization method and (2) considering relative humidity as a key factor for efficacy testing.

In recent years, there have been numerous recalls of frozen vegetable products due to Listeria monocytogenes contamination, which causes listeriosis. In pregnant women, listeriosis can cause miscarriage, stillbirth, and other serious complications. Manufacturing guidelines are created with the intention that frozen vegetables will be cooked prior to consumption. However, consumers may prepare and eat frozen vegetables without prior cooking. Therefore, it is necessary to assess behaviors that could be risky for L. monocytogenes exposure. A 10-question online survey was distributed to women between the ages of 18–54 to investigate frozen vegetable consumption behaviors. The prevalence of uncooked frozen vegetable consumption, reading preparation instructions, and listeriosis knowledge was assessed. Data were analyzed using logistic and ordered logit regression. Of 1,001 complete responses, 531 (53%) indicated that they consumed frozen vegetables in the past week, and of those 35.6% (n = 189) indicated that they consumed frozen vegetables without prior heating. Women who had not heard of listeriosis and had not read preparation instructions had significantly higher odds of uncooked frozen vegetable consumption (Odds Ratio (OR): 2.30, 95% Confidence Interval (CI): 1.48, 3.55; OR: 1.85, 95% CI: 1.13, 3.01, respectively). These results will guide future research on safe food handling practices for frozen vegetable products. The findings support the need for updating public health guidelines to include frozen vegetables as foods that are risky for listeriosis in pregnancy. Additionally, these findings have implications for future research to inform food policy governing labeling regulation on frozen vegetable products to reflect current consumer behavior.