Indiana health department workers responded to reports of an increase in the number of salmonellosis cases in the state. Salmonella I 4,[5], 12:i:- monophasic was isolated from case-patient stool samples. A food history questionnaire was sent to all case-patients. Over 75% of the case-patients shared an exposure to a specific Wal-Mart deli. The same questionnaire was also sent to controls who were not ill, but lived in the same zip code as the ill people. This case-control study found significant association between illness and eating food purchased from the Wal-Mart deli. This information led to an environmental investigation of the deli/bakery area at the Wal-Mart. Two employee stool samples tested positive for the outbreak strain, as did a knife holding block. The employees were removed from food handling positions until their infection cleared, and the block was discarded.