A spore-forming bacterium that causes food poisoning when cooked meats, poultry and gravies are cooled too slowly or held at unsafe temperatures.
Meat, poultry, stews, casseroles, curries and gravies cooked in large quantities and then cooled slowly or held warm are the usual sources. It is often tied to catered events and bulk cooking.
Symptoms usually start 6 to 24 hours after eating and include abdominal cramps and diarrhoea. Vomiting and fever are uncommon, and most people recover within a day or two.
Cooking kills the growing bacteria but not the heat-resistant spores. If the food then cools too slowly, the spores germinate and multiply, so rapid cooling and correct hot-holding are the real controls.
Outbreaks are strongly associated with food cooked in bulk and held for long periods, which is common in catering and cafeterias. Large volumes of food cool slowly and give the bacteria time to grow.
Cool food quickly using shallow containers, hold hot food at 60 degrees or above, and reheat rapidly to 60 degrees or hotter. Keeping food out of the temperature danger zone is the main safeguard.