In September 1994 the Minnesota Department of Health noted a sharp increase in reports of Salmonella Enteritidis infections. A few weeks later, the FDA and state health officials determined that contaminated ice cream was the likely cause. The ice cream products were distributed nationwide by a brand of ice cream, Schwan's. The attack rate for consumers was 6.6 percent. Overall, 593 confirmed cases with no deaths were reported among persons who ate Schwan's ice cream. Forty-one states reported confirmed or probable cases. However investigators estimated that 224,000 persons in the United States developed Salmonella Enteritidis after they ate Schwan's Ice cream

Investigators suspected that raw, unpasteurized eggs were hauled in one or more tanker trucks that later carried pasteurized ice cream premix to the Schwan's ice cream processing plant. Salmonella was isolated from ice cream, but not from the ice cream processing plant. A study of Schwan's customers showed an increased risk of gastrointestinal illness after consumption of Schwan's ice cream.