Canadian Journal of Microbiology
Enterococcus faecium WEFA23 is a potential probiotic strain isolated from Chinese infant feces. In this study, the antagonistic activity of E. faecium WEFA23 on adhesion to pathogens was investigated. Enterococcus faecium WEFA23 was able to compete, exclude, and displace the adhesion of Escherichia coli O157:H7, Salmonella Typhimurium ATCC 13311, Listeria monocytogenes CMCC54007, Staphylococcus aureus CMCC26003, and Shigella sonnei ATCC 25931 to Caco-2 cells. Among them, L. monocytogenes achieved the strongest inhibition rate in both competition and displacement assays. Those anti-adhesion capacities were related to the bacterial physicochemical properties (hydrophobicity, auto-aggregation, and co-aggregation) of the bacterial surface. For L. monocytogenes, the anti-adhesion capacity was affected by the heat treatment, cell density, and growth phase of E. faecium WEFA23; 108 colony-forming units of viable cells per millilitre at the stationary phase exhibited the strongest anti-adhesion activity. In addition, removal of S-layer proteins of E. faecium WEFA23 by treatment with 5 mol/L LiCl significantly decreased its adhesion capacity, and those S-layer proteins were able to compete, displace, and exclude L. monocytogenes at different levels. Both cells and S-layer proteins of E. faecium WEFA23 significantly reduced the apoptosis of Caco-2 cells induced by L. monocytogenes, which was mediated by caspase-3 activation. This study might be helpful in understanding the anti-adhesion mechanism of probiotics against pathogens.
RASFF – Enterococcus (42 CFU/250ml) in crushed ice from Italy in Italy
Posted in Enterococcus, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, food recall, Food Safety, Food Safety Alert, Food Testing, Uncategorized
We have today published the results of a survey we commissioned to assess the amount of antimicrobial resistance (AMR) in bacteria in fresh pork mince and fresh and frozen chicken on sale in shops in the UK. These findings will help to establish a baseline of the occurrence, types and levels of AMR in bacteria found in these UK retail meats which will inform future surveillance on AMR in these foods.
This survey follows on from an authoritative report by a group established by the Advisory Committee on Microbiological Safety of Food (ACMSF) to advise us on research questions and potential approaches to AMR in the food chain.
The survey involved the testing of Campylobacter in chicken samples and Salmonella in pork mince samples for the occurrence of antimicrobial resistant bacteria. The survey also looked for AMR in other bacteria in both types of meat including Enterococci, Klebsiella and Escherichia coli. Read the final report of the survey.
Background: Cross contamination in the kitchen could contribute to home-based food poisoning. This study aimed at investigating the potential role of kitchen towels in cross contamination in the kitchen. Methods: A total of 100 kitchen towels were collected after one month of use. The bacteria were cultured and identified by standard biochemical tests. A questionnaire was also designed to investigate the potential risk factors which could affect the result. Results: Bacterial growth was found in 49% of the kitchen towels and significantly increased by size of family, extended family and presence on children. Multipurpose towels had higher CFU than single use towels (1.31 x 107 vs 6.60 x 104; p<0.05) and humid towels had higher CFU than dry ones (4.8 x 105 vs 0.5x 105; p<0.05). The mean CFU from the towels was found to be 2.76 x 105 and was significantly higher from the cotton towels (4.98 x 105) compared to the nylon (1.64 x 105) and mixture of both towels (1.89 x 105). Out of the 49 samples which were positive for bacterial growth, 36.7% grew coliforms, 36.7% Enterococcus spp., 30.6% Pseudomonas spp., 28.6% grew Bacillus spp., 14.3% S. aureus, 4.1% Proteus spp., 2.0% coagulase negative Staphylococcus. Furthermore, S. aureus was isolated at higher rate from families of lower socio-economic status (p<0.05) and those with children (p<0.05). The risk of having coliforms was twice on humid towels than the dried ones. It was also noted that as the CFU increased, the detection rate of coliform, Enterococcus spp., Proteus spp. and Bacillus spp. also increased significantly. Furthermore, Enterococcus spp. and S. aureus were isolated at higher prevalence in bigger families (p<0.05). Diet was also found to be an important factor. Coliform and S. aureus were detected at significantly higher prevalence from families on non-vegetarian diets while a higher prevalence of Enterococcus species from the kitchen towels of vegetarian families. Conclusions: This study conclude that kitchen towels could be very important source bacterial contamination which could contribute to food poisoning. The multipurpose usage of kitchen towels should be discouraged.
Posted in Bacillus, Bacillus cereus, Bacteria, Coliforms, Enterococcus, Proteus, Pseudomonas, Pseudomonas aeruginosa, Research, Staphylococcus aureus, Uncategorized
The effect of microbial control measures in farmstead cheese making was evaluated in a small dairy farm in Gyeong‐gi province, Korea. Teat washing and pasteurization significantly (p < .05) reduced the level of indicator bacteria (mesophilic aerobes, total coliforms, and Escherichia coli). However, farmstead cheeses were contaminated with increased levels of mesophilic aerobes, total coliforms, Staphylococcus aureus, and Enterococcus faecium during post‐pasteurization steps, including the cheesemaking process and ripening. S. aureus isolates from cheese samples exhibited antibiotic resistance to penicillin/ampicillin, whereas teat and milk samples showed resistance to erythromycin/ciprofloxacin. Enterococcus spp. isolates had the highest proportion of organisms resistant to erythromycin and tetracycline among multidrug‐resistant strains. To ensure the safety of farmstead cheese, customized management systems and intervention methods should be established by focusing on control measures for not only preprocessing and pasteurization but also post‐pasteurization steps.
Owing to renewed interest in specialty cheeses, small‐scale farmstead cheeses are actively produced worldwide. However, because of various manufacturing steps, including milking, pasteurization, ripening, and storage, farmstead cheese could pose a high risk for the presence of foodborne pathogens. In the current study, teat washing and milk pasteurization effectively reduced microbial contamination loads. However, farmstead cheeses were contaminated post‐pasteurization with increased levels of indicator and pathogenic microorganisms. Comprehensive management systems should be implemented and should focus not only on preprocessing and pasteurization but also on post‐pasteurization steps to ensure the safety of farmstead cheese.
The presence and antimicrobial susceptibility of foodborne pathogens and indicator organisms in animal feed are not well understood. In this study, a total of 201 feed ingredient samples (animal byproducts, n=122; plant byproducts, n=79) were collected in 2002 and 2003 from representative rendering plants and the oilseed (or cereal grain) industry across the United States. The occurrence and antimicrobial susceptibility of four bacterial genera (Salmonella, Campylobacter, Escherichia coli, and Enterococcus) were determined. Salmonella isolates were further characterized by serotyping and pulsed-field gel electrophoresis (PFGE). None of the samples yielded Campylobacter or E. coli O157:H7, whereas Salmonella, generic E. coli, and Enterococcus were present in 22.9%, 39.3%, and 86.6% of samples, respectively. A large percentage (47.8%) of Salmonella-positive samples harbored two serovars, and the vast majority (88.4%) of Enterococcus isolates were E. faecium. Animal byproducts had a significantly higher Salmonella contamination rate (34.4%) than plant byproducts (5.1%) (p<0.05). Among 74 Salmonella isolates recovered, 27 serovars and 55 PFGE patterns were identified; all were pan-susceptible to 17 antimicrobials tested. E. coli isolates (n=131) demonstrated similar susceptibility to these antimicrobials except for tetracycline (15.3% resistance), sulfamethoxazole (7.6%), streptomycin (4.6%), ampicillin (3.8%), and nalidixic acid (1.5%). Enterococcus isolates (n=362) were also resistant to five of 17 antimicrobials tested, ranging from 1.1% to penicillin to 14.6% to tetracycline. Resistance rates were generally higher among isolates recovered from animal byproducts. Taken together, our findings suggest that diverse populations of Salmonella, E. coli, and Enterococcus are commonly present in animal feed ingredients, but antimicrobial resistance is not common. Future large-scale studies to monitor these pathogenic and indicator organisms in feed commodities is warranted.
Posted in Antibiotic Resistance, Antimicrobials, Bacteria, Campylobacter, E.coli, Enterococcus, Food Microbiology, Food Poisoning, Food Safety, Food Testing, Laboratory, Microbiology, Pathogen, Research, Salmonella
Tagged animal feed ingredients, environment, field gel electrophoresis, salmonella contamination, science
Food Safety News
Ground turkey from birds raised without antibiotics is less likely to be contaminated with antibiotic-resistant bacteria than conventional ground turkey, according to a new study published by Consumer Reports today.
The group tested 257 samples of raw ground turkey meat and patties, purchased from major retailers nationwide, for Enterococcus, E. coli, Staphylococcus aureus, Salmonella, and Campylobacter and then looked at what portion of these bacteria were resistant to antibiotics. They found high levels of bacteria overall – 90 percent of samples tested positive for one of the five – and more than half were resistant to three or more classes of antibiotics. But the bugs found in products labeled “no antibiotics,” “organic,” or “raised without antibiotics” were resistant to fewer antibiotics than their conventional counterparts.
Posted in Bacteria, Campylobacter, E.coli, Enterococcus, Food Hygiene, Food Illness, Food Micro Blog, Food Microbiology, Food Poisoning, Food Safety, Food Technology, Food Testing, Foodborne Illness, Microbiology, Pathogen, Research, Salmonella, Staphylococcus aureus
Tagged classes of antibiotics, food safety news, health, staphylococcus aureus