Foodborne Illness Source Attribution Estimates for Salmonella, Escherichia coli O157 (E. coli O157), Listeria monocytogenes (Lm), and Campylobacter using Outbreak Surveillance Data
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Tag Archives: escherichia coli o157
Research – Persistence of Escherichia coli O157 and non-O157 Strains in Agricultural Soils
Shiga toxin producing Escherichia coli O157 and non-O157 serogroups are known to cause serious diseases in human. However, research on the persistence of E. coli non-O157 serogroups in preharvest environment is limited. In the current study, we compared the survival behavior of E. coli O157 to that of non-O157 E. coli strains in agricultural soils collected from three major fresh produce growing areas of California (CA) and Arizona (AZ). Results showed that the nonpathogenic E. coli O157:H7 4554 survived longer than the pathogenic E. coli O157:H7 EDL933 in Imperial Valley CA and Yuma AZ, but not in soils from the Salinas area. However, E. coli O157:NM was found to persist significantly longer than E. coli O157:H7 EDL933 in all soil tested from the three regions. Furthermore, two non-O157 (E. coli O26:H21 and E. coli O103:H2) survived significantly longer than E. coli O157:H7 EDL933 in all soils tested. Pearson correlation analysis showed that survival of the E. coli strains was affected by different environmental factors. Our data suggest that survival of E. coli O157 and non-O157 may be strain and soil specific, and therefore, care must be taken in data interpretation with respect to survival of this pathogen in different soils.
Posted in Uncategorized
Tagged E. coli, E. coli strains, E.coli O157, escherichia coli o157
Research Netherlands – Microbial Risk in Produce
The objective of this study was to evaluate the microbial hazard associated with the consumption of mixed salads produced under standard conditions. The presence of Salmonella, Campylobacter spp., and Escherichia coli O157 in the Dutch production chain of mixed salads was determined. Microbial prevalence and concentration data from a microbiological surveillance study were used as inputs for the quantitative microbial risk assessment. Chain logistics, production figures, and consumption patterns were combined with the survey data for the risk assessment chain approach. The results of the sample analysis were used to track events from contamination through human illness. Wide 95% confidence intervals around the mean were found for estimated annual numbers of illnesses resulting from the consumption of mixed salads contaminated with Salmonella Typhimurium DT104 (0 to 10,300 cases), Campylobacter spp. (0 to 92,000 cases), or E. coli (0 to 800 cases). The main sources of uncertainty are the lack of decontamination data (i.e., produce washing during processing) and an appropriate dose-response relationship.
Recent outbreaks with vegetable or fruits as vehicles have raised interest in the characterization of the public health risk due to microbial contamination of these commodities. Because qualitative and quantitative data regarding prevalence and concentration of various microbes are lacking, we conducted a survey to estimate the prevalence and contamination level of raw produce and the resulting minimally processed packaged salads as sold in The Netherlands. A dedicated sampling plan accounted for the amount of processed produce in relation to the amount of products, laboratory capacity, and seasonal influences. Over 1,800 samples of produce and over 1,900 samples of ready-to-eat mixed salads were investigated for Salmonella enterica serovars, Campylobacter spp., Escherichia coli O157, and Listeria monocytogenes. The overall prevalence in raw produce varied between 0.11% for E. coli O157 and L. monocytogenes and 0.38% for Salmonella. Prevalence point estimates for specific produce/pathogen combinations ranged for Salmonella from 0.53% in iceberg lettuce to 5.1% in cucumber. For Campylobacter, this ranged from 0.83% in endive to 2.7% in oak tree lettuce. These data will be used to determine the public health risk posed by the consumption of ready-to-eat mixed salads in The Netherlands.
Posted in Bacteria, Campylobacter, E.coli O157, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Safety, Food Testing, Hygiene, Microbiology, Pathogen, Research, Salmonella
Tagged campylobacter, Campylobacter spp, consumption patterns, escherichia coli o157, quantitative microbial risk assessment, salmonella
Research – Effect of Pickling on Pathogens in Hard Boiled Eggs
Traditional methods of food preservation, such as pickling, have reemerged as popular approaches for home and commercial food processing. The process of pickling hard-cooked eggs (HCE) can be an effective method of preventing the growth and survival of pathogenic microorganisms. Because of the variety of pickling processes, HCE manufacturers must validate their pickling process for Food and Drug Administration (FDA) approval and demonstrate 5-log reductions of pathogens associated with the product. In this study, a rapid one-step pickling process was evaluated for its ability to reduce Salmonella spp., Listeria monocytogenes, Staphylococcus aureus and Escherichia coli O157:H7 inoculated onto HCE for 14 days at room temperature. All pathogens inoculated onto HCE were reduced by (>5.0 logs) within 24 h and were undetectable following enrichment. The data obtained in this study may be of interest to regulatory officials and processors of HCE seeking pathogen reduction validation for their products.
Posted in Bacteria, E.coli O157, Food Hygiene, Food Micro Blog, Food Microbiology, Food Safety, Food Safety Alert, Food Testing, Listeria monocytogenes, Microbiology, Pathogen, Salmonella, Staphylococcus aureus
Tagged escherichia coli o157, hard cooked eggs, methods of food preservation, research, science
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