Meat Safety News Digest

Differences in E. coli O157:H7 strain colonization and shedding patterns in cattle American researchers conducted oral challenge studies with three different genotypes of E. coli O157:H7 in cattle to determine the genotypic variability in shedding frequencies and concentrations and the extent of contamination of the environment. Four groups of Holstein steers each were orally challenged with 10 CFU of one of the three E. coli O157:H7 strains. Recto-anal mucosal swabs and environmental samples were taken on alternate days over 30 days. The numbers of E. coli O157:H7 and generic E. coli were determined by the presence and absence of 28 gene targets using real-time PCR. Over the study period, strains were found in varying frequencies (52%, 42%, and 2% of swabs, respectively). Environmental detection of the challenge strains was found mainly in samples of the hides and pen floors. Based on the analysis of 28 genes, genotypes of enterohaemorrhagic E. coli (EHEC) and generic E. coli were clustered into three subgroups. The researchers concluded that the type and intensity of measures to control this pathogen at the pre-harvest level may need to be strain-specific. http://aem.asm.org/content/early/2012/09/04/A EM.02363-12.short?rss=1 O157 AND NON-O157 SEROGROUP COMPARISONS