What is Bacillus cerus?
Bacillus cerus is a bacteria found in soil and dust. Rice is the most common food associated with Bacillus cereus but it may also be found in other foods including:
herbs and spices and vanilla
What are spores?
Spores are a resistant form of the bacillus cereus bacteria that allow it to survive normal cooking, dehydration and even disinfectants.
Bacillus cereus is one of many bacteria that produce spores. Spores are not a significant risk to a healthy adult however if we allow food the conditions required for the spores to germinate into bacteria then food poisoning could occur. Spores and bacteria require, warmth, moisture time and a nutrient source to multiply. Once rice is cooked the bacteria have the required moisture and nutrient source required for multiplication.
If the food is not cooled quickly after cooking and then refrigerated (1°C and 4°C) the spores may germinate into bacteria and then continue to multiply.
When the bacteria multiply they produce toxins (poison), the toxin is heat resistant so subsequent reheating is of little value as a control for the Bacillus cereus toxin.
Symptoms of Bacillus Cereus food poisoning
Toxin in food (most common)
Onset period: 1 to 6 hours
Symptoms: Vomiting, abdominal pain and some diarrhoea (12-24 hours)
Toxin in intestine
Onset period: 6 to 24 hours
Symptoms: Abdominal pain, diarrhoea and some vomiting (1 to 2 days)
Controls to prevent Bacillus cereus food poisoning
Rapid cooling and storage in a fridge between 1°C and 4°C
Reheat thoroughly to a minimum of 75°C
ONLY REHEAT ONCE! (and throw away any leftovers)
Rice and other items may be used in cold food dishes but must be refrigerated while stored or displayed, once removed from the fridge the cold rice should be eaten or discarded within 4 hours.
Please note that this is not an authoritative interpretation of the law and is intended only for guidance.