Investigations indicated that Escherichia coli O157:H7 is an emerging cause of foodborne illness and that young dairy cattle are a reservoir for it. A particularly dangerous type is referred to as enterohemorrhagic E. coli (EHEC). Infection with EHEC strains often associated with foodborne outbreaks traced to milk, dairy products, and other foods lead to hemorrhagic colitis (bloody diarrhea) and hemolytic uremic syndrome in humans .