The products subject to recall bear the establishment number “EST. 2574B” and will have a production date code in the format “Packing Nos: MM DD 14” between “03 31 14” and “04 18 14”. These products were shipped to distributors for restaurant use in Massachusetts, Michigan, Missouri, and Ohio. [Editor's Note: Late in the day on May 19, FSIS officials added a note to the original announcement, stating that the agency now believes the recalled product was sent to distribution centers nationwide.] There was no distribution of the products to the Department of Defense, the National School Lunch Program, or catalog/internet sales.

Factors that can contribute to the size of the recall include potential contamination of additional products due to a lack of microbiological independence between lot production, as well as a deficiency in supportive record-keeping by distributors.

FSIS was notified of E. coli O157:H7 illnesses on May 12, 2014. Working in conjunction with public health partners from the Centers for Disease Control and Prevention (CDC), FSIS determined that there is a link between the ground beef products from Wolverine Packing Company and this illness cluster. Based on epidemiological and traceback investigations, 11 case-patients have been identified in 4 states with illness onset dates ranging from April 22 to May 2, 2014. FSIS continues to work with our state and federal public health partners on this investigation and provide updated information as it becomes available.

MLive.com reported that in Michigan, five residents became ill after eating undercooked hamburger in various restaurants. Two of those people were hospitalized but are said to be recovering, and no deaths have been reported. In addition, the article stated, "Michigan Department of Community Health reports that no new cases have been reported since the five patients were diagnosed between April 22 and May 1." MLive.com first reported on the illnesses May 14 after one person was hospitalized.