Escherichia coli O157:H7 outbreak linked to home-cooked hamburger--California, July 1993.

Although outbreaks of Escherichia coli O157:H7 have been linked to consumption of contaminated ground beef, the organism is rarely isolated from the implicated meat. In addition, most epidemiologic investigations of illness associated with E. coli O157:H7 infections have been directed at restaurant-associated outbreaks, and the sources of infection for sporadic cases rarely have been identified. In July 1993, three cases of culture-confirmed E. coli O157:H7 infection among persons residing in a small community in California were traced to consumption of hamburger purchased from a local grocery store; E. coli O157:H7 was isolated from that meat. This report summarizes the investigation of these cases by local and state public health officials.