To investigation and analyze the causes and characteristics of a food poisoning incident caused by Clostridium perfringens in schools, so as to provide a reference for prevention and control of food poisoning incidents.

From March 11 to 12, 2024, on-site epidemiological and hygienic investigations were conducted by using food poisoning case questionnaires and on-site hygienic investigation forms in Shenzhen. Information related to the poisoning incident was collected through field investigations and telephone interviews. A case-control study was used to analyze the suspected food responsible for the incident. Risk analysis in χ² analysis was used to obtain OR values.

The Clostridium perfringens food poisoning incident involved two schools, with a cumulative total of 52 cases. School A had an attack rate of 2.21%(45/2 040), school B had an attack rate of 1.29% (7/544). The main clinical symptoms were diarrhea (100.00%) and abdominal pain (84.62%), with a minority experiencing fever (3.85%). Analysis via the case-control study indicated that consuming mushroom and meat sauce during lunch on March 11, 2024, was a risk factor for the poisoning incident (OR=124.50, 95%CI=14.53-937.51, P < 0.05). On-site investigation revealed that the mushroom and meat sauce provided by the schools on March 11 was prepared by the catering company the previous day, stored without refrigeration, and not reheated before serving the next day. A total of 31 patient anal swabs, 16 food samples, and 14 kitchen staff anal swabs were sent for laboratory testing. Clostridium perfringens was isolated from 22 case samples. Among these, type A Clostridium perfringens (alpha toxin) was detected in 8 case samples, 4 kitchen staff anal swabs, and 2 retained samples of the mushroom and meat sauce.

The incident is a food poisoning outbreak caused by Clostridium perfringens contamination in schools. Avoiding cross-contamination and ensuring proper storage are key to preventing Clostridium perfringens food poisoning.