Presence of Shiga toxin-producing Escherichia coli O-groups in small and very-small beef-processing plants and resulting ground beef detected by a multiplex polymerase chain reaction assay.

Shiga toxin-producing Escherichia coli (STEC) are associated with foodborne illnesses, including hemolytic uremic syndrome in humans. Cattle and consequently, beef products are considered a major source of STEC. E.