Opinion of the Scientific Panel on biological hazards (BIOHAZ) related to Clostridium spp in foodstuffs

This is the authors' abstract. We don't add key points for this paper.

Anaerobic spore-forming bacteria spoil a wide range of foods including dairy products, meat and poultry products, fresh and canned fruits and vegetables, typically producing gas and/or putrid odours.A few of those species can cause illness.The species of the genus Clostridium most commonly involved in food-borne illness are Clostridium perfringens and C. botulinum.Intoxication due to C. perfringens is usually brief, self-limiting, and is rarely fatal.However, the neurotoxins of C. botulinum are among the most toxic naturally-occurring substances and cause severe food-borne illness, sometimes fatal, with symptoms continuing for several months.Clostridia occur commonly in soil, dust, the aquatic environment and in the intestines of animals.Consequently, C. perfringens and C. botulinum can be present in a wide range of foods.Good Agricultural Practices and Good Hygienic Practices contribute to reducing numbers of clostridia by minimising contamination with soil and animal faeces.C. perfringens is commonly present in foods and ingredients, occasionally at hundreds per gram.C. botulinum is present less frequently, normally at a few spores per kg.Spores of both C. perfringens and C. botulinum can be eliminated from foods by heating. C. perfringensIllness due to C. perfringens occurs after ingestion of large numbers of enterotoxinproducing vegetative cells after food has been temperature-abused, either during cooling after a heat process, or stored unrefrigerated, both of which allow spores to germinate and multiply.Illnesses due to C. perfringens are commonly associated with cooked meat, cooked uncured meat products, the associated gravy, casseroles, or pea soup produced on a large scale, at mass catering in food service establishments, care homes and similar establishments.Almost all outbreaks are the result of cooling slowly, or holding without refrigeration, allowing multiplication of C. perfringens, numbers reaching 10 6 -10 7 /g, and implying an infective dose of the order 10 8 of vegetative cells of enterotoxin-producing C. perfringens.Some vegetative cells survive the acid conditions of the stomach and subsequently form spores in the large intestine, at the same time producing enterotoxin.Because the illness lasts only 12-24 h, and the symptoms are usually not serious enough to consult a physician, recorded cases and outbreaks are probably under-reported.Occasionally death occurs, usually in elderly patients.The enterotoxin of C. perfringens is heat labile, heating at 60°C for 5 min destroying the biological activity.The most essential measures to prevent foodborne diseases caused by C. perfringens are: appropriate cooking, cooling rapidly through the temperature range 55°C to 15°C, holding foods at temperatures <10°-12°C, and re-heating the product to an internal temperature of 72°C before consumption.Microbiological testing for C. perfringens has limited value in ensuring food safety, because the organism is so common in or on foods that a positive result means little, unless very high numbers are present.Moreover, cultural methods detect all C. perfringens, while enterotoxin is produced by only a fraction of strains. ANNEX Annex I Compliance Guidelines for Cooling Heat-Treated Meat and Poultry Products (Stabilization).