Objective To investigate and analyze the epidemiological characteristics of an outbreak of foodborne disease in school K， explore key procedures and response measures for on-site management of such outbreaks， and to provide a basis for the future management and prevention of similar incidents.Methods Descriptive epidemiological methods were used to analyze the epidemiological characteristics of the event. A case-control study was employed to investigate and validate suspected meals， dining locations， and foods. Environmental hygiene surveys were conducted to identify potential contamination processes. Laboratory tests were performed on biological specimens from affected students， food handlers in the school cafeteria， food samples，and food processing environment samples to confirm the pathogen.Results The outbreak exposed 3，985 individuals， with 83 cases reported （attack rate： 2.08%）. Among 89 tested samples， 19 （21.35%） were positive for S.aureus producing enterotoxin type A . Core genome multilocus sequence typing （cgMLST） clustering analysis revealed that 17 S.aureus， isolated from chicken cutlets， knives and cutting boards used for processing chicken，food handlers， and affected students， shared homology. This confirmed contamination of the chicken cutlets with S.aureus producing enterotoxin type A from handlers or the environment.Conclusion This outbreak was caused by consumption of chicken cutlets contaminated by S.aureus producing enterotoxin type A from food handlers or the environment in School K. The evidence chain was complete. Timely collection of patient specimens for multiplex PCR testing enabled rapid identification of potential pathogens. and whole-genome sequencing technologies improved the etiological confirmation rate in foodborne disease outbreak investigations.