Food Safety Report: Culver's, 13th Avenue Southwest, Fargo, ND, USA 2 years ago • details 35 Comments Comment Suspected food poisoning. Symptoms: Diarrhea, Nausea, Stomach Pain, Cramps, Headache Suspected source: Frozen custard Onset: Less than 4 hours Duration: 12 to 24 hours Sick: Me Additional information: Concrete mixer.