Food Safety Report: Costco Wholesale, North Western Avenue, Oklahoma City, Oklahoma, USA 1 year ago • details 29 Suspected food poisoning. Symptoms: Diarrhea Suspected source: Ate costco chicken salad for 2 lunch 2 days in a row and have had diarrhea for 2 days along with cramping. Onset: Less than 4 hours Duration: 12 to 24 hours Sick: Me