RESUMEN
Argentina has the highest incidence of HUS in the world. HUS is produced by STEC O157 and non-O157. Cattle's faeces and hides are sources of STEC contamination of carcasses during slaughter. We investigated the presence of STEC in carcasses and cuts of meat in the marketing chain in an agricultural city located in Buenos Aires Province (Argentina). In this study, the detection of the stx gene was used as an indicator of carriage of meat with STEC. In carcasses, we detected 12.34% and 18.64% of STEC at the slaughter and sanitary control cabin (place where carcasses arrive from slaughters located outside the city), respectively. These percentages increased at butcheries (24.52%). The 25% of retail beef cuts were STEC-positive with significant differences among the different cuts of meat (chuck: 12.12%, rump roast: 12.12% and minced beef: 40.74%). The stx2 gene was the predominant gene detected in all samples at different levels of the commercialization meat chain.