In February 2004, Japanese health workers investigated three cases of Escherichia coli O157:H7 infection in a Japanese family associated with eating ground beef that had been purchased from a U.S. military commissary in Okinawa. The investigation resulted in a voluntary recall of the frozen ground beef from the United States and from U.S. military bases in the Far East. Ultimately a total of four cases were documented in Japan, and two were documented in Orange County, California. The frozen ground beef patties eaten by the Japanese family were purchased from a U.S. military commissary in Okinawa. The same strain of E. coli O157:H7 that had been isolated from the case-patients was isolated from a consumer and from unpened package samples of ground beef patties. Traceback of the ground beef indicated that it was produced on August 11, 2003, by a U.S. company. Fresh and frozen ground beef products produced on that day were distributed to U.S. military installations in the Far East and to institutional and retail outlets in California, Idaho, Oregon, and Washington. The Americans had eaten hamburger patties from the same lot before the recall had been issued.