Clostridium perfringens outbreak associated with minestrone soup

Area of Science:

• Foodborne illness epidemiology
• Microbiology of food spoilage
• Public health surveillance

Background:

• Clostridium perfringens (C. perfringens) is a common cause of food poisoning, typically associated with meat and poultry.
• Food safety practices are crucial in preventing outbreaks, especially concerning temperature control during food preparation and storage.

Purpose of the Study:

• To investigate the cause of a gastrointestinal illness outbreak among conference attendees.
• To identify the food vehicle responsible for the Clostridium perfringens outbreak.
• To assess the role of non-animal protein sources in C. perfringens food poisoning.

Main Methods:

• A survey of conference attendees to collect data on symptoms and food consumption.
• Bacteriological analysis of food samples and stool specimens from ill individuals.
• Calculation of relative risk to determine the association between food consumption and illness.

Main Results:

• Out of 42 attendees, 32 (76%) reported gastrointestinal symptoms with a median incubation period of 6.5 hours.
• Minestrone soup was identified as the likely vehicle, with ill attendees being almost five times more likely to have consumed it (RR=4.92).
• C. perfringens was confirmed in the minestrone soup and in stool samples from ill attendees.

Conclusions:

• Improper cooling and reheating of minestrone soup facilitated Clostridium perfringens proliferation.
• Non-animal protein sources, like legumes in minestrone, can support C. perfringens growth and should be considered potential outbreak vehicles.
• This outbreak underscores the importance of strict time and temperature controls in food preparation to prevent C. perfringens food poisoning.