Starting in early March, Federal food inspectors will expand E coli testing to six serogroups recently defined as contaminants.

The USDA’s Food Safety and Inspection Service said in early December the agency will begin testing in March. In addition to E coli O157:H7, the agency will test six additional shiga toxin–producing E coli (STEC) serogroups: O26, O45, O103, O111, O121 and O145.

The Center for Disease Control and Prevention estimates about 110,000 human illnesses were connected to food-borne non-O157 STEC annually from 2000 to 2008 while food-born STEC O157 strains were connected to about 63,000 per year in the same timeframe.

Undercooked beef is a primary source of the food and environmental sources of STEC according to the Center for Disease Control and Prevention.