Abstract: OBJECTIVE To analyze the causes of food poisoning and provide references for improving food hygiene and safety management. METHODS The epidemiological survey was conducted through individual case interviews with patients, on-site inspection of food processing premises, and laboratory testing of leftover food. A full-chain traceability investigation covering food procurement to processing was simultaneously carried out to comprehensively identify the source of food contamination. RESULTS A total of 66 cases of food poisoning occurred in No. 4 Canteen of a certain unit, the median incubation period was 4.0 (3.5 to 5.0) hours. A case-control study showed that consumption of the "garlic-flavored boneless pork elbow" was significantly associated with the onset of illness (χ²=18.267, P＜0.001). All of the 66 patients had eaten the off-odor "garlic-flavored boneless pork elbow", while none of the non-consumers developed symptoms. The predominant clinical manifestations were vomiting (89.39%) and diarrhea (78.78%), and the levels of white blood cell (WBC) and C-reactive protein were higher than the normal values. One cook who were involved in preparing the dish had an infected purulent wound on the hand and performed bare-handed food handling. The cooked dish was stored at room temperature for over 27 hours and was not reheated at high temperature before serving. Staphylococcus aureus and gene fragments of staphylococcal enterotoxin A (SEA) were detected in the reserved samples of the implicated dish. CONCLUSIONS The clustered outbreak is an incident of food poisoning caused by staphylococcal enterotoxin A, and it is inferred that the contamination with the cook's purulent hand wound is attributed to the food poisoning, while operational errors in food storage and reheating are the critical contributing factors for the poisoning.