In early June, 2007, four Salmonella I 4,[5],12:i:- infections sharing a pulsed-field gel electrophoresis (PFGE) pattern were identified by the Pennsylvania Department of Health. As additional cases were reported, the initial investigation did not reveal the cause of the infections. A multistate, case-control study conducted in early October indicated that illness was associated with consumption of Banquet brand frozen, not ready-to-eat, pot pies. Further investigation determined that 77% of patients who ate these pies had microwaved them. Consumer confusion might have resulted in a failure to cook the product properly. A voluntary recall was issued by ConAgra, the manufacturer on October 11, 2007, for all nine brands of pot pies produced at the implicated plant. The outbreak strain was isolated from at least thirteen samples of unopened Banquet pot pies collected from the homes of patients. All pies that tested positive were turkey pot pies. Two of the pies underwent separate testing of filling and crust. The filling tested positive and the crust tested negative for both pies. Cooking instructions were not validated to account for variability in microwave wattage and common misconceptions among consumers regarding the nature of not-ready-to-eat foods. The involved plant had produced one million pies per day under various store brands. Frozen, not-ready-to-eat microwavable meals have been reported previously as vehicles in salmonellosis outbreaks. Despite an intensive investigation of the production plant and the ingredient suppliers, the source of the contamination remains unknown.