INCOMPLETE SANITATION OF A MEAT GRINDER AND INGESTION OF RAW GROUND-BEEF - CONTRIBUTING FACTORS TO A LARGE OUTBREAK OF SALMONELLA-TYPHIMURIUM INFECTION

Consumers in the United States continue to eat raw or undercooked food s of animal origin despite public health warnings following several we ll-publicized outbreaks. We investigated an outbreak of Salmonella ser otype Typhimurium infection in 158 patients in Wisconsin during the 19 94 Christmas holiday period. To determine the vehicle and source of th e outbreak, we conducted cohort and case-control studies, and environm ental investigations in butcher shop A. Eating raw ground beef purchas ed from butcher shop A was the only item significantly associated with illness [cohort study: relative risk = 5.8, 95% confidence interval ( CI) = 1.5-21.8; case control study: odds ratio = 46.2, 95% CI = 3.8-27 51]. Inadequate cleaning and sanitization of the meat grinder in butch er shop A likely resulted in sustained contamination of ground beef du ring an 8-day interval. Consumer education, coupled with hazard reduct ion efforts at multiple stages in the food processing chain, will cont inue to play an important role in the control of foodborne illness.