E. coli Infection
What is E. coli infection?
E. coli infection is a type of food-borne illness caused by bacteria called Escherichia coli. It affects the digestive tract and, in serious cases, the kidneys. There are many strains of E. coli, and most are harmless.
E. coli are also used as indicators of water and food quality, and the bacteria can tell us if there is fecal contamination in the water or food.
The strain of E. coli that most often makes people sick is E. coli O157:H7. For ease, we will refer to E. coli O157:H7 as E. coli.
What are the symptoms?
Symptoms of E.coli infection include:
- watery diarrhea, which in serious cases may become bloody;
- stomach cramps; and,
- mild fever.
The symptoms can start 2 to 10 days after eating food contaminated with E.coli, but usually start within 3 to 4 days. Symptoms can last between 5 to 10 days.
In a few cases, E. coli can cause a serious and sometimes fatal illness called hemolytic uremic syndrome (HUS) which can result in kidney failure, anemia and internal bleeding. HUS can be especially harmful for young children, the elderly, people with impaired immune systems, and pregnant women.
Where does the disease come from?
E. coli can be found in the stomachs and manure of many healthy animals including cattle, goats, sheep, deer, and elk.
During the butchering process, E. coli sometimes gets onto the surface of the meat. Whole cuts of meat such as steaks or roasts usually only have E. coli on the surface, which makes the E. coli easier to kill by cooking. When the meat is ground or mechanically tenderized, E. coli on the surface can be transferred to the inside of the meat. This is why ground meat and mechanically tenderized meat are more likely to cause illness than whole cuts of meat. E. coli can be killed if the meat is cooked thoroughly. Infection can happen when people eat undercooked hamburgers or ground meat.
E. coli are also sometimes found in other foods including fruits and vegetables, as well as in unpasteurized milk, juice, cider, and untreated water.
Contaminated drinking water can also cause infections, as can swimming in contaminated recreational water that drains cattle pastures.
How do I avoid getting sick?
To reduce the risk of E. coli infection:
- Refrigerate or freeze meat as soon as possible after buying it.
- Always thaw meat thoroughly in the refrigerator before you start to cook it. Ensure it is wrapped well and kept away from other foods. Do not try cooking frozen or partially frozen meat.
- Wash your hands thoroughly before preparing food, after handling raw meat, and after using the toilet as E.coli can be spread to others through infected feces.
- Always wash and then sanitize all utensils, cutting boards and counters that have touched raw meat to prevent E. coli from contaminating other foods. Make an effective sanitizing solution by mixing 5 ml (1 teaspoon) of bleach in 1 litre (4 ¼ cups) of water.
- Properly cook the outside of all whole cuts of meats such as steaks, roasts or chops by searing or cooking them quickly with high heat to kill E. coli on the surface.
- Cook ground meat, such as hamburger patties, meat loaf, rolled roasts (beef roulade) and mechanically tenderized meat until the middle reaches a temperature of 71°C (160°F) or hotter and remains there for at least 15 seconds. Measure the internal temperature of the meat with a good probe thermometer.
- Never put cooked meat back on the same unwashed surface that held the raw meat. The juices from the raw meat can be contaminated with E. coli, which can then contaminate the cooked meat.
- Do not use marinade as a sauce on cooked meat.
- Serve cooked meats right away or keep them hot. They should be at least 60°C (140°F) or hotter, until you are ready to serve them.
- Wash any fruits and vegetables with cold running water before eating them raw, even if they will be peeled or cut. Use a scrub brush on fruits and vegetables with rough skin, such as a cantaloupe.
- Avoid drinking unpasteurized milk, juice and cider.
- Do not drink or use untreated surface water from a spring, stream, river, lake, pond or shallow well. Assume it is contaminated with animal feces.
- Avoid swimming in water that may drain pastureland.
In B.C., water is routinely tested for generic E. coli (non-O157:H7) contamination.
Is there a treatment for the disease?
Anyone who has diarrhea for more than a few days and/or bloody diarrhea should see a health care provider.
Drinking lots of clear fluids is important to replace lost fluids and prevent dehydration. Do not take anti-diarrhea medicine unless you first talk to your health care provider.
Serious cases may require hospitalization, blood transfusion, and dialysis.
For more information about food safety, see the following HealthLinkBC Files:
#03 Pasteurized and Raw Milk
#22 Home Canning - How to Avoid Botulism
#59a Food Safety: Ten Easy Steps to Make Food Safe
#59b Food Safety for Fresh Fruits and Vegetables
#59c Food Safety: Instructions on Food Labels
#59d Food Safety in Child Care Facilities
#72 Unpasteurized Fruit Juices and Ciders: A Potential Health Risk
#76 Foods to Avoid for People at Higher Risk of Food-borne Illness