Published
What is it?
- Bacillus cereus (B. cereus) is a type of bacteria widespread in the environment
- It can form spores and toxins that are not destroyed by cooking or boiling
What's the risk?
- B. cereus can cause vomiting and diarrhoea
- Anyone can get sick with B. cereus but vulnerable people (i.e. young children, pregnant women, the elderly) and people with weak immune systems (like cancer patients) can get seriously ill
- Foods at higher risk of contamination include pre-cooked starchy foods like rice, pasta and cereals, and pre-cooked mixed dishes, especially dishes with spices
What illness does it cause?
There are two types of illness: emetic (vomiting) and diarrhoeal.
Neither of these illnesses are nationally notifiable (they don't need to be reported to health authorities unless there is an outbreak - linked illness in two or more people).
Symptoms of illness from B. cereus
- Symptoms usually start 1 to 16 hours after eating contaminated food. Common symptoms are nausea, vomiting, abdominal cramps, and watery diarrhoea
- Most people only have mild symptoms and recover quickly (within a day or less)
Reduce your risk
- Cook food thoroughly and serve it immediately or keep it hot (60°C or hotter) before serving
- Cool cooked food quickly if it is going to be used later:
- put it in the fridge (or freezer) as soon as it stops steaming
- divide large amounts of hot food into smaller containers to let it cool faster
- make sure your fridge is 5oC or colder
- Keep leftovers in the fridge (or freezer) and dispose of refrigerated leftovers if not eaten within 3-4 days (or within 1 day for vulnerable people)
- Wash your hands with soap and dry them before preparing and eating food
- Keep your kitchen and equipment clean
Page last updated: 13 March 2025