A Maricopa County school hosted a catered fundraiser in May. Shortly after the event, the school reported that a number of attendees had gastrointestinal distress. The local health department investigated the illnesses and gathered food histories. This information allowed officials to determine that ice cream and frozen yogurt dispensed from a soft serve machine at the event were significantly associated with illness. Environmental testing was performed on the machine. These tests were positive for bacteria. Further investigation found employees had been ill prior to the event. Stool samples tested positive for Norovirus. The investigation concluded that ill food workers contaminated the frozen treats, but there may also have been bacterial intoxication as well.