Food Safety Report: Canned Clam Chowder, Walmart, Olivette, MO, USA 7 months ago • details 8 Suspected food poisoning. Symptoms: Diarrhea, Stomach Pain, Chills, Headache Suspected source: clam chowder Onset: 12 to 24 hours Duration: 4 to 12 hours Sick: Me Additional information: old bay clam chowder?