isolation and molecular characterization of non-sorbitol fermenting escherichia coli isolated from fresh ground beef

conclusions the observed results indicated the necessity of good care in abattoir, butcheries and during food distribution, mainly ground beef. also, a zero tolerance policy could be useful to control e. coli o157 in meat products nationwide. results overall, 1.5% of ground beef samples were contaminated with the o157 e. coli strain meanwhile 1% of samples contained the o157:h7 strain and 0.5% of samples had the o157:h7 with virulent stx1 and stx2 genes. materials and methods a total of 200 fresh ground beef were sampled during a six-month period. all samples were enriched in tryptic soy broth (tsb) with novobiocin and plating on cefixime telluride-sorbitol macconkey (ct-smac). the suspected colonies were subjected to polymerase chain reaction (pcr) analysis to identify virulence genes containing rfbe o157, flic h7, stx1 and stx2 genes. background escherichia coli o157:h7 (ehec) has been traditionally associated with foodborne infections from consumption of foods with animal origin such as ground beef and burgers. objectives the objective of this study was to investigate the contamination of fresh ground beef with non-sorbitol fermenting escherichia coli and presence of virulence genes in isolates obtained from butchers located in ahvaz, iran.