Evaluation of Salmonella Biofilm Cell Transfer from Common Food Contact Surfaces to Beef Products

Meat contamination by Salmonella enterica is a serious public health concern. Available data have suggested that biofilm formation at processing plants and contaminated contact surfaces might contribute to meat contamination. Because transfer from contact surfaces to food products via direct contact has been deemed the most common bacteria transmission route that can lead to contamination, we evaluated the effect of Salmonella biofilm forming ability, contact surface material, and beef surface tissue type on Salmonella biofilm transfer from hard surfaces to beef products. Salmonella biofilms developed on the common contact surfaces stainless steel (SS) and polyvinylchloride (PVC) were transferred consecutively via 30 s of direct contact to either lean muscle or adipose tissue surfaces of 15 pieces of beef trim. The Salmonella biofilm cells could be effectively transferred multiple times from the contact surfaces to the beef trim as indicated by quantifiable Salmonella cells on most meat samples. Biofilm forming ability had the most significant impact (P \u3c 0.05) on transfer efficiency. More cells of Salmonella strains that formed strong biofilms were transferred after each contact and contaminated more meat samples with quantifiable cells compared with strains that formed weak biofilms. Contact surface materials also affected transferability. Salmonella biofilms on SS transferred more efficiently than did those on PVC. In contrast, the two types of meat surface tissues were not significantly different (P \u3e 0.05) in biofilm transfer efficiency. Beef trim samples that were in contact with biofilms but did not have quantifiable Salmonella cells were positive for Salmonella after enrichment culture. Our results indicate the high potential of Salmonella biofilms on common contact surfaces in meat processing plants to cause product cross-contamination

Efficacy of Hypobromous Acid as a Hide-On Carcass Antimicrobial Intervention

Escherichia coli O157:H7 and Salmonella on cattle hides at slaughter are the main source of beef carcass contamination by these foodborne pathogens during processing. Hypobromous acid (HOBr) has been approved for various applications in meat processing, but the efficacy of HOBr as a hide antimicrobial has not been determined. In this study, the antimicrobial properties of HOBr were determined by spraying cattle hides at either of two concentrations, 220 or 500 ppm. Treatment of hides with 220 ppm of HOBr reduced the prevalence of E. coli O157:H7 on hides from 25.3 to 10.1% (P , 0.05) and reduced the prevalence of Salmonella from 28.3 to 7.1% (P \u3c 0.05). Treatment of hides with 500 ppm of HOBr reduced (P , 0.05) the prevalence of E. coli O157:H7 on hides from 21.2 to 10.1% and the prevalence of Salmonella from 33.3 to 8.1%. The application of 220 ppm of HOBr reduced (P \u3c 0.05) aerobic plate counts, total coliform counts, and E. coli counts on hides by 2.2 log CFU/100 cm2. The use of 500 ppm of HOBr resulted in reductions (P \u3c 0.05) of aerobic plate counts, total coliform counts, and E. coli counts by 3.3, 3.7, and 3.8 log CFU/100 cm2, respectively, demonstrating that the use of higher concentrations of HOBr on hides resulted in additional antimicrobial activity. These results indicate that the adoption of a HOBr hide wash will reduce hide concentrations of spoilage bacteria and pathogen prevalence, resulting in a lower risk of carcass contamination

Efficacy of Hypobromous Acid as a Hide-On Carcass Antimicrobial Intervention

Escherichia coli O157:H7 and Salmonella on cattle hides at slaughter are the main source of beef carcass contamination by these foodborne pathogens during processing. Hypobromous acid (HOBr) has been approved for various applications in meat processing, but the efficacy of HOBr as a hide antimicrobial has not been determined. In this study, the antimicrobial properties of HOBr were determined by spraying cattle hides at either of two concentrations, 220 or 500 ppm. Treatment of hides with 220 ppm of HOBr reduced the prevalence of E. coli O157:H7 on hides from 25.3 to 10.1% (P , 0.05) and reduced the prevalence of Salmonella from 28.3 to 7.1% (P \u3c 0.05). Treatment of hides with 500 ppm of HOBr reduced (P , 0.05) the prevalence of E. coli O157:H7 on hides from 21.2 to 10.1% and the prevalence of Salmonella from 33.3 to 8.1%. The application of 220 ppm of HOBr reduced (P \u3c 0.05) aerobic plate counts, total coliform counts, and E. coli counts on hides by 2.2 log CFU/100 cm2. The use of 500 ppm of HOBr resulted in reductions (P \u3c 0.05) of aerobic plate counts, total coliform counts, and E. coli counts by 3.3, 3.7, and 3.8 log CFU/100 cm2, respectively, demonstrating that the use of higher concentrations of HOBr on hides resulted in additional antimicrobial activity. These results indicate that the adoption of a HOBr hide wash will reduce hide concentrations of spoilage bacteria and pathogen prevalence, resulting in a lower risk of carcass contamination

Efficacy of Antimicrobial Interventions Used in Meat Processing Plants against Antimicrobial Tolerant Non–Antibiotic-Resistant and Antibiotic-Resistant Salmonella on Fresh Beef

Salmonella is a common cause of foodborne illness in the United States, and several strains of Salmonella have been identified as resistant to antibiotics. It is not known whether strains that are antibiotic resistant (ABR) and that have some tolerance to antimicrobial compounds are also able to resist the inactivation effects of antimicrobial interventions used in fresh meat processing. Sixty-eight Salmonella isolates (non-ABR and ABR strains) were treated with half concentrations of lactic acid (LA), peracetic acid (PAA), and cetylpyridinium chloride (CPC), which are used in beef processing plants to screen for tolerant strains. Six strains each from non-ABR and ABR Salmonella that were most tolerant of LA (2%), PAA (200 ppm), and CPC (0.4%) were selected. Selected strains were inoculated on surfaces of fresh beef and subjected to spray wash treatment with 4% LA, 400 ppm PAA, or 0.8% CPC for the challenge study. Tissue samples were collected before and after each antimicrobial treatment for enumeration of survivors. Spray treatment with LA, PAA, or CPC significantly reduced non-ABR Salmonella and ABR Salmonella on surfaces of fresh beef by 1.95, 1.22, and 1.33 log CFU/cm2, and 2.14, 1.45, and 1.43 log CFU/cm2, respectively. The order of effectiveness was LA . PAA = CPC. The findings also indicated that LA, PAA, and CPC were equally (P ≤ 0.05) effective against non-ABR and ABR Salmonella on surfaces of fresh beef. These data contribute to the body of work that indicates that foodborne pathogens that have acquired both antibiotic resistance and antimicrobial tolerance are still equally susceptible to meat processing antimicrobial intervention treatments

The impact of the bovine faecal microbiome on \u3ci\u3eEscherichia coli\u3c/i\u3e O157:H7 prevalence and enumeration in naturally infected cattle

Aims: The objective of this study was to determine if the faecal microbiome has an association with Escherichia coli O157:H7 prevalence and enumeration. Methods and Results: Pyrosequencing analysis of faecal microbiome was performed from feedlot cattle fed one of three diets: (i) 94 heifers fed low concentrate (LC) diet, (ii) 142 steers fed moderate concentrate (MC) diet, and (iii) 132 steers fed high concentrate (HC) diet. A total of 322 585 OTUs were calculated from 2,411,122 high-quality sequences obtained from 368 faecal samples. In the LC diet group, OTUs assigned to the orders Clostridiales and RF39 (placed within the class Mollicutes) were positively correlated with both E. coli O157:H7 prevalence and enumeration. In the MC diet group, OTUs assigned to Prevotella copri were positively correlated with both E. coli O157: H7 prevalence and enumeration, whereas OTUs assigned to Prevotella stercorea were negatively correlated with both E. coli O157:H7 prevalence and enumeration. In both the MC diet group and the HC diet group, OTUs assigned to taxa placed within Clostridiales were both positively and negatively correlated with both E. coli O157:H7 prevalence and enumeration. However, all correlations were weak. In both the MC diet group and the HC diet group, stepwise linear regression through backward elimination analyses indicated that these OTUs were significantly correlated (P \u3c 0.001) with prevalence or enumeration, explaining as much as 50% of variability in E. coli O157:H7 prevalence or enumeration. Conclusions: Individual colonic bacterial species have little impact on E. coli O157:H7 shedding but collectively groups of bacteria were strongly associated with pathogen shedding. Significance and Impact of the Study: Bacterial groups in the bovine colon may impact faecal shedding of the zoonotic pathogen E. coli O157:H7, and manipulation of the intestinal microbiota to alter these bacteria may reduce shedding of this pathogen and foodborne illnesses

Investigation of bacterial diversity in the feces of cattle fed different diets

The objective of this study is to investigate individual animal variation of bovine fecal microbiota including as affected by diets. Fecal samples were collected from 426 cattle fed 1 of 3 diets typically fed to feedlot cattle: 1) 143 steers fed finishing diet (83% dry-rolled corn, 13% corn silage, and 4% supplement), 2) 147 steers fed late growing diet (66% dry-rolled corn, 26% corn silage, and 8% supplement), and 3) 136 heifers fed early growing diet (70% corn silage and 30% alfalfa haylage). Bacterial 16S rRNA gene amplicons were determined from individual fecal samples using next-generation pyrosequencing technology. A total of 2,149,008 16S rRNA gene sequences from 333 cattle with at least 2,000 sequences were analyzed. Firmicutes and Bacteroidetes were dominant phyla in all fecal samples. At the genus level, Oscillibacter, Turicibacter, Roseburia, Fecalibacterium, Coprococcus, Clostridium, Prevotella, and Succinivibrio were represented by more than 1% of total sequences. However, numerous sequences could not be assigned to a known genus. Dominant unclassified groups were unclassified Ruminococcaceae and unclassified Lachnospiraceae that could be classified to a family but not to a genus. These dominant genera and unclassified groups differed (P \u3c 0.001) with diets. A total of 176,692 operational taxonomic units (OTU) were identified in combination across all the 333 cattle. Only 2,359 OTU were shared across 3 diet groups. UniFrac analysis showed that bacterial communities in cattle feces were greatly affected by dietary differences. This study indicates that the community structure of fecal microbiota in cattle is greatly affected by diet, particularly between forage- and concentrate-based diets

Extrakorporale hydrostatische Hochdruckbehandlung als neues Verfahren zur Desinfektion infizierter Knochenpräparate

Background: Allogeneic bone transplantation is at risk of infection, and established disinfection methods typically compromise bone quality. High hydrostatic pressure (HHP) is well established for disinfection in food technology, and also it does protect biomechanical and biological properties of bone. This study is the first investigation of HHP regarding disinfection of bone biopsies. Materials and methods: Bone biopsies of 34 patients with chronic infections were subjected to HHP and assessed for persisting bacterial growth. In series 1, bone biopsies were proceeded directly to HHP (10 min; maximal pressure P-max 600 MPa). In series 2, HHP was applied after 5-day incubation in growth media (10 min or 2 x 30 min; P-max 600 MPa). Furthermore, HHP-induced changes of bacterial morphology on artificially infected bone samples were evaluated by scanning electron microscopy (SEM). Results: For series 1, 71% of the bone samples were sterilised by HHP (n = 17), compared to 38% of the untreated control samples, which were obtained during the same surgery (n = 8). For series 2, after prior incubation, HHP disinfected 7% of the bone specimens (n = 55), all control samples showed bacterial growth (n = 33). Destruction of cell wall integrity of Gram-negative strains was observed by SEM. Conclusion: The effectiveness of HHP for bone disinfection should be improved by optimising treatment parameters. Infections with barosensitive Gram-negative bacteria or yeast might represent possible clinical indications

Seasonal Prevalence of Shiga Toxin-Producing Escherichia coli on Pork Carcasses for Three Steps of the Harvest Process at Two Commercial Processing Plants in the United States

Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen that has a significant impact on public health, with strains possessing the attachment factor intimin referred to as enterohemorrhagic E. coli (EHEC) and associated with life-threatening illnesses. Cattle and beef are considered typical sources of STEC, but their presence in pork products is a growing concern. Therefore, carcasses (n = 1,536) at two U.S. pork processors were sampled once per season at three stages of harvest (poststunning skins, postscald carcasses, and chilled carcasses) and then examined using PCR for Shiga toxin genes (stx), intimin genes (eae), aerobic plate count (APC), and Enterobacteriaceae counts (EBC). The prevalence of stx on skins, postscald, and chilled carcasses was 85.3, 17.5, and 5.4%, respectively, with 82.3, 7.8, and 1.7% of swabs, respectively, having stx and eae present. All stx-positive samples were subjected to culture isolation that resulted in 368 STEC and 46 EHEC isolates. The most frequently identified STEC were serogroups O121, O8, and O91 (63, 6.7, and 6.0% of total STEC, respectively). The most frequently isolated EHEC was serotype O157:H7 (63% of total EHEC). Results showed that scalding significantly reduced (P 75%) cases of severe illnesses caused by STEC and are considered adulterants of beef. However, some STEC outbreaks have been attributed to pork products, although the same E. coli are not considered adulterants in pork because little is known of their prevalence along the pork chain. The significance of the work presented here is that it identifies disease-causing STEC, EHEC, demonstrating that these same organisms are a food safety hazard in pork as well as beef. The results show that most STEC isolated from pork are not likely to cause severe disease in humans and that processes used in pork harvest, such as scalding, offer a significant control point to reduce contamination. The results will assist the pork processing industry and regulatory agencies to optimize interventions to improve the safety of pork products.Supplementary material: [https://vet-erinar.vet.bg.ac.rs/handle/123456789/2030]This is the peer-reviewed version of the following article: Nastasijevic, I.; Schmidt, J. W.; Boskovic, M.; Glisic, M.; Kalchayanand, N.; Shackelford, S. D.; Wheeler, T. L.; Koohmaraie, M.; Bosilevac, J. M. Seasonal Prevalence of Shiga Toxin-Producing Escherichia Coli on Pork Carcasses for Three Steps of the Harvest Process at Two Commercial Processing Plants in the United States. Appl. Environ. Microbiol. 2020, 87 (1). [https://doi.org/10.1128/AEM.01711-20

Supplementary data for article: Nastasijevic, I.; Schmidt, J. W.; Boskovic, M.; Glisic, M.; Kalchayanand, N.; Shackelford, S. D.; Wheeler, T. L.; Koohmaraie, M.; Bosilevac, J. M. Seasonal Prevalence of Shiga Toxin-Producing Escherichia Coli on Pork Carcasses for Three Steps of the Harvest Process at Two Commercial Processing Plants in the United States. Appl. Environ. Microbiol. 2020, 87 (1). https://doi.org/10.1128/AEM.01711-20.

Supplementary material for: [https://doi.org/10.1128/AEM.01711-20]Related to published version: [https://vet-erinar.vet.bg.ac.rs/handle/123456789/2029