Escherichia coli (E. coli) bacteria normally live in the intestines of healthy people and animals. Most varieties of E. coli are harmless or cause relatively brief diarrhoea. But a few particularly nasty strains, such as E. coli O157:H7, can cause severe abdominal cramps, bloody diarrhoea and vomiting.
You may be exposed to E. coli from contaminated water or food — especially raw vegetables and under cooked ground beef. Healthy adults usually recover from infection with E. coli O157:H7 within a week, but young children and older adults can develop a life-threatening form of kidney failure called hemolytic uremic syndrome (HUS).
Among the many strains of E. coli, only a few trigger diarrhoea. One group of E. coli — which includes O157:H7 — produces a powerful toxin that damages the lining of the small intestine, which can cause bloody diarrhoea. You develop an E. coli infection when you ingest this strain of bacteria. Potential sources of exposure include contaminated food or water, and person-to-person contact.
E. coli can affect anyone who is exposed to the bacteria. But some people are more likely to develop problems than are others.
Risk factors include:
• Age. Young children and older adults are at higher risk of experiencing illness caused by E. coli and more-serious complications from the infection.
• Weakened immune systems. People who have weakened immune systems — from AIDS or drugs to treat cancer or to prevent the rejection of organ transplants — are more likely to become ill from ingesting E. coli.
• Eating certain types of food. Riskier foods include under cooked hamburger; unpasteurised milk, apple juice; and soft cheeses made from raw milk.
To diagnose illness caused by E. coli infection, your doctor will send a sample of your stool to a laboratory to test for the presence of E. coli bacteria. The bacteria may be cultured to confirm the diagnosis and identify specific toxins
To reduce your chance of being exposed to E. coli, avoid risky foods and watch out for cross-contamination.
Risky food
• Avoid pink hamburger. Hamburgers should be well-done. Meat, especially if grilled, is likely to brown before it’s completely cooked, so use a meat thermometer to ensure that meat is heated to at least 160 F (71 C) at its thickest point. If you don’t have a thermometer, cook ground meat until no pink shows in the centre.
• Drink pasteurised milk and juice. Any boxed or bottled juice kept at room temperature is likely to be pasteurised, even if the label doesn’t say so.
• Wash raw produce thoroughly. Although washing produce won’t necessarily get rid of all E. coli — especially in leafy greens, which provide many spots for the bacteria to attach themselves to — careful rinsing can remove dirt and reduce the amount of bacteria that may be clinging to the produce.
Avoid cross-contamination
• Wash utensils. Use hot soapy water on knives, counter tops and cutting boards before and after they come into contact with fresh produce or raw meat.
• Keep raw foods separate. This includes using separate cutting boards for raw meat and foods such as vegetables and fruits. Never put cooked hamburgers on the same plate you used for raw patties.
• Wash your hands. Wash your hands after preparing or eating food, using the bathroom, or changing diapers. Make sure that children also wash their hands before eating, after using the bathroom and after contact with animals.
