Factors affecting fecal shedding of Escherichia coli O157:H7 in cattle

Cattle are reservoirs of E. coli O157:H7 and contamination of carcasses during slaughter transfer this potentially deadly pathogen into the human food chain. The goal of this study was to assess: 1) the effect of feeding cattle corn or wheat DDGS, a by-product of the bioethanol industry on fecal shedding or persistence of E. coli O157:H7 in cattle; 2) the effect of endemic bacteriophages on fecal shedding of E. coli O157:H7 in cattle. Results from this study suggest addition of DDGS in finishing diets of cattle do not affect the fecal shedding or persistence of E. coli O157:H7. Three types of endemic phages were identified which may impact levels of shedding of E. coli O157:H7 in cattle. Improved understanding of factors which contribute to shedding of E. coli O157:H7 and the natural microbiota of individual cattle will improve upon existing systems to reduce E. coli O157:H7 in meat.