MDH conducted a case-control study; seventeen people met the case definition. Of these, three people developed hemolytic uremic syndrome (HUS), and one patient died. Attendance at the church’s July 19 smorgasbord dinner was significantly associated with illness.
MDA and MDH learned that ground beef used to make meatballs for the church meal, as well as the ground beef served by numerous area restaurants, was purchased at Tabaka’s Supervalu, and conducted a trace-back investigation to determine the source of the ground beef. Investigators found that Supervalu sold ground beef from its July 10 shipment of chuck rolls supplied by Interstate Meat to three Longville restaurants in the same time period as the sale to church members.
The MDA traceback of the chuck rolls from Interstate Meat revealed that the “most plausible” source of the chuck rolls delivered to the Supervalu store was the Nebraska Beef processing plant. In addition to this, the USDA reported that a sample of beef trimmings collected on June 14, 2006 at a processing plant cultured positive for E. coli O157:H7, and that the isolate was indistinguishable by PFGE analysis to the outbreak strain. The processing plant was determined to be Nebraska Beef, the company that most likely supplied the implicated chuck rolls to Tabaka’s Supervalu.
Ultimately, MDH concluded that ground beef sold by Tabaka’s Supervalu was the source of the E. coli O157:H7 outbreak in Longville and that the ground beef was likely contaminated at the Nebraska Beef facility before it was received at the Supervalu store.