Shiga Toxin–Producing Escherichia coli: Pre- and Postharvest Control Measures To Ensure Safety of Dairy Cattle Products

Abstract

The large number of cases of human illness caused by Shiga toxin–producing Escherichia coli (STEC) worldwide has raised safety concerns for foods of bovine origin. These human illnesses include diarrhea, hemorrhagic colitis, hemolytic uremic syndrome, and thrombotic thrombocytopenic purpura. Severe cases end with chronic renal failure, chronic nervous system deficiencies, and death. Over 100 STEC serotypes, including E. coli O157:H7, are known to cause these illnesses and to be shed in cattle feces. Thus, cattle are considered reservoirs of these foodborne pathogens. Because beef and dairy products were responsible for a large number of STEC outbreaks, efforts have been devoted to developing and implementing control measures that assure safety of foods derived from dairy cattle. These efforts should reduce consumers' safety concerns and support a competitive dairy industry at the production and processing levels. The efficacy of control measures both before harvest (i.e., on-farm management practices) and after harvest (i.e., milk processing and meat packing) for decreasing the risk of STEC contamination of dairy products was evaluated. The preharvest measures included sanitation during milking and management practices designed to decrease STEC prevalence in the dairy herd (i.e., animal factors, manure handling, drinking water, and both feeds and feeding). The postharvest measures included the practices or treatments that could be implemented during processing of milk, beef, or their products to eliminate or minimize STEC contamination.