Contamination of sheep carcasses with verocytotoxin producing Escherchia coli during slaughtering

Verocytotoxin producing Escherchia coli (VTEC) infection has been associated with diarrhoea. Sheep, like other ruminants, appear to have VTEC in their feces and are regarded as natural reservoirs of these pathogens. As contaminated sheep products can serve as a risk factor, their role as a food safety threat should be considered. The carcasses of sheep during slaughtering were examined for the presence of VTEC, which were isolated from 19 (9.5%) of 200 animals. Most of the 19 VTEC isolates (73.68%) contained Shiga toxin 1 and 2 genes. Eight (4%) carcasses of sheep were contaminated by E. coli O157:H7. The monthly prevalence of VTEC in sheep was obtained and ranged from 0.2% to 9.5% and was at its highest level in spring and late summer, which is in parallel to the seasonal variation in reported cases of O157 VTEC infections in humans. This study showed that VTEC are widely distributed in southern Iranian sheep.