A gut bacterium whose harmful strains, such as Shiga toxin-producing E. coli, can cause severe illness.
A gut bacterium whose harmful strains, such as Shiga toxin-producing E. coli, can cause severe illness. Escherichia coli, usually shortened to E. coli, is a bacterium that normally lives in the intestines of people and animals. Most strains are harmless, but some, in particular Shiga toxin-producing E. coli (STEC, which includes strains such as O157), can cause serious foodborne illness. These strains are found in the gut of cattle and other ruminants and can contaminate meat, unpasteurised milk, and fresh produce exposed to animal faeces or contaminated water. Illness from harmful E. coli ranges from mild diarrhoea to severe bloody diarrhoea and, in some cases, a serious complication called haemolytic uraemic syndrome (HUS), which can damage the kidneys and is most dangerous for young children and the elderly. The presence of E. coli in food or water is also widely used as an indicator of faecal contamination and poor hygiene. Food businesses control harmful E. coli by cooking minced meat and other high-risk foods thoroughly, since grinding spreads any surface bacteria through the product. Burgers, sausages and other minced products should be cooked so they are no longer pink in the centre and reach safe core temperatures. Using pasteurised milk and juices and washing fresh produce also reduces risk. Preventing cross-contamination from raw meat to ready-to-eat food, maintaining good hand hygiene, and using safe water are all important. Because E. coli signals faecal contamination, its detection in testing points to a breakdown in hygiene or handling that a business needs to investigate and correct. A takeaway cooks beef burgers quickly on a busy night and serves some patties still pink in the middle. Shiga toxin-producing E. coli in the mince survives because the centre did not reach a safe temperature, and a young child who eats one becomes seriously ill. Cooking minced meat thoroughly to a safe core temperature would have destroyed the bacteria.
Frequently asked questions
Are all E. coli harmful?
No. Most E. coli strains are harmless and live normally in the gut. Only certain strains, such as Shiga toxin-producing E. coli, cause serious foodborne illness, but its presence is used as a sign of faecal contamination.
What foods are linked to harmful E. coli?
Undercooked minced meat such as burgers and sausages, unpasteurised milk and juice, and fresh produce contaminated by animal faeces or dirty water are the most common sources.
Why is mince a particular risk for E. coli?
Mincing spreads any bacteria from the surface of the meat throughout the product, so the centre must be cooked thoroughly. Whole cuts have bacteria mainly on the surface, which searing kills.
What is haemolytic uraemic syndrome?
HUS is a serious complication of some E. coli infections that can cause kidney failure. It is most dangerous for young children and older adults and requires urgent medical care.
How can businesses reduce E. coli risk?
Cook minced meat thoroughly, use pasteurised milk and juice, wash produce, prevent cross-contamination from raw meat, use safe water and maintain good hand hygiene.
