Reports of illness following a brunch in Bloomington, Minnesota, on April 11, prompted an investigation by the local health department. The health department received five independent reports of illness on April 13, and issued a press release indicating a possible outbreak on April 16. The press release caused ten more people to phone in complaints. An investigation into the cause of this cluster began on April 13 with the first complaints. The restaurant that served the brunch closed on that day to protect the public. A guest list from the brunch was used to contact potential cases and gather food histories. Initial interviews of patrons found 115 cases. Seven employees also met the case definition. Stool samples were collected from five patrons and four tested positive for Norovirus. Employee stool samples also tested positive for the same strain of Norovirus. A case-control study was conducted to identify the contaminated food. Statistical analysis found two possible foods, the fruit tray or beets, associated with illness. Two of the employees who reported illness worked preparing these foods.