Laboratory confirmation of an outbreak of Clostridium perfringens food poisoning

A foodborne outbreak in a group of eleven individuals sharing a common meal, eight of whom reported symptoms and an incubation period compatible with Clostridium perfringens food poisoning, was confirmed by the following laboratory criteria: (a) the C. perfringens count in the suspect food, chicken pie, was at least 10(5) per gram; (b) the median fecal C. perfringens spore count in convalescing patients was greater than 10(6) per gram: (c) an indentical serotype (PS63) was isolated from both the food and fecal specimens; and (d) the C. perfringens isolates from most of the patients (8 out of 10) were of the same serotype. The results confirm the usefulness of fecal spore counts and serotyping in implicating C perfringens in food poisoning outbreaks.