A company notified the Minnesota State Health Department when twenty to thirty employees complained of gastrointestinal distress after a company sponsored lunch of submarine sandwiches. Epidemiologists investigated the restaurant that supplied the sandwiches and they conducted telephone interviews with other patrons. These interviews found additional cases related to eating submarine sandwiches prepared by the restaurant. Stool samples yielded Norovirus. The environmental investigation of the restaurant found bare-hand contact with vegetables prior to placement on sandwiches. This was determined to be the likely route of contamination, though none of the food workers reported illness. A meaningful case-control study to identify a specific food was not possible due to the lack of non-ill controls.