Tests conducted on commercial ground beef identified disease-causing E. coli that could be considered significant food safety threats, according to the authors of a new study.

Results of these latest tests support earlier studies that have shown the presence of non-O157 Shiga toxin-producing E. coli (STEC) in the retail meat supply, particularly in ground beef.

According to estimates by the Centers for Disease Control and Prevention, these non-O157 STEC cause more than 36,700 illnesses each year.

Only E. coli O157:H7 has been classified as an adulterant in U.S. beef, but these non-O157 STEC also can harm human health and have become an increasing concern, the study notes.

“The data clearly show that clinical and public health laboratories should routinely screen human and environmental specimens for the presence of non-O157,”  the scientists conclude. Currently most labs do not.

The study, by Joseph M. Bosilevac of the U.S. Department of Agriculture’s Agriculture Research Service and Mohammad Koohmaraie, College of Food and Agriculture, King Saud University, was published Jan. 21, 2011 in the American Society for Microbiology’s Applied and Environmental Microbiology journal. 

Authors of an earlier study in Maryland, which found 10 E. coli serotypes in retail meat products, concluded that their testing “demonstrated that retail meats, mainly ground beef, were contaminated with diverse STEC strains.”

Independent tests commissioned by the Seattle food safety firm Marler Clark, sponsor of Food Safety News, also demonstrated the prevalence of non-O157 STEC in the retail ground beef supply.  Marler Clark has petitioned the USDA’s Food Safety and Inspection Service to declare STEC as adulterants.