An outbreak of E. coli O157:H7 was associated with eating nationally distributed steaks that were produced by the National Steak and Poultry Company of Owasso, Oklahoma. The steaks were sold in restaurants and were blade tenderized by National Steak and Poultry prior to further processing and cooking at the restaurants. The contamination has resulted in illness in sixteen states. At least five restaurant chains were known to have received the beef (Darden Restaurants such as Applebee's Neighborhood Grill & Bar and Olive Garden, Moe's Southwest Grill, Carino's Italian, and KRM, Inc., owner of 15 54th Street Grill & Bar locations). The Minnesota case had not eaten at restaurants, but instead reported eating ground beef. A traceback identified a possible common beef supplier to multiple plants that produced steak or ground beef, however the traceback evidence was not sufficiently strong to conclusively implicate this company. The CDC assigned cluster ID 0912MLEXH-1 to the investigation.