Starting next Monday, the U.S. Department of Agriculture's (USDA) Food Safety and Inspection Service (FSIS) will begin routinely testing raw beef manufacturing trim, which is a major component of ground beef, for six additional strains of E. coli as part of a zero-tolerance policy. Trim found to be contaminated with these pathogens will not be allowed into commerce and will be subject to recall.

Illnesses due to E. coli serogroups other than O157:H7, which caused a high-profile illness outbreak in 1993, outnumber those attributed to O157:H7. FSIS declared O157:H7 an adulterant in 1994.

"These strains of E. coli are an emerging threat to human health and the steps we are taking are entirely focused on preventing Americans from suffering foodborne illnesses," said Agriculture Secretary Tom Vilsack. "We cannot ignore the evidence that these pathogens are a threat in our nation's food supply."

The additional strains that will be treated as adulterants include Shiga-toxin producing E. coli (STEC) serogroups O26, O45, O103, O111, O121 and O145. Like E. coli O157:H7, these serogroups can cause severe illness and even death. Young children and the elderly are at highest risk, according to USDA.