Food poisoning caused by Clostridium perfringens may occur when foods such as meat or
poultry are cooked and held without maintaining adequate heating or refrigeration before
serving. The presence of small numbers of C. perfringens is not uncommon in raw meats,
poultry, dehydrated soups and sauces, raw vegetables, and spices. Because the spores of some
strains are resistant to temperatures as high as 100°C for more than l h, their presence in foods
may be unavoidable. Furthermore, the oxygen level may be sufficiently reduced during cooking
to permit growth of the clostridia. Spores that survive cooking may germinate and grow rapidly
in foods that are inadequately refrigerated after cooking. Thus, when clinical and
epidemiological evidence suggests that C. perfringens is the cause of a food poisoning
outbreak, the presence of hundreds of thousands or more of these organisms per gram of food
substantiates the diagnosis.
Illness typically occurs 8-15 h after ingestion of the contaminated food. The symptoms, which
include intense abdominal cramps, gas, and diarrhea (nausea and vomiting are rare), have been
attributed to a protein enterotoxin produced during sporulation of the organism in the intestine.
The enterotoxin can be detected in sporulating cultures, and a method for this purpose is
included. A high correlation has been established between the ability of C. perfringens strains to
produce enterotoxin and their ability to cause food poisoning. However, it is difficult to obtain
consistent sporulation with some strains.
C. perfringens cells lose their viability when foods are frozen or held under prolonged
refrigeration unless special precautions are taken. Such losses may make it difficult to establish
C. perfringens as the specific cause of a food poisoning outbreak. It is recommended that
samples which cannot be examined immediately be treated with buffered glycerin-salt solution
and stored or shipped frozen to the laboratory as described below.