E. Coli

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What is E Coli?

E. coli are germs, more specifically referred to as bacteria. Most strains of E. coli are harmless and make up the normal flora in the intestinal tracts of all warm-blooded animals, including humans. However, a few of the E. coli strains are not healthy and are capable of causing human illness.

Some strains of E. coli can cause diarrhea, while others cause urinary tract infections, respiratory illness and pneumonia, and other illnesses. A particularly dangerous type called E. coli O157:H7 often causes bloody diarrhea due to severe damage to the lining of the intestine, and also can lead to kidney failure in children or people with weakened immune systems.

E. coli is one of the bacteria that can be a cause of food poisoning. Harmful bacteria can grow in cooked and raw meat and fish, dairy products, and prepared foods left at room temperature too long. You can also get food poisoning after eating food contaminated by viral or chemical agents as well.

What are the causes of E. coli infection?

  • Cattle are the main sources of E. coli O157:H7, and undercooked or raw ground beef has been implicated in many E. coli O157:H7 disease outbreaks among humans, but other domestic and wild mammals also can harbor these bacteria.

  • Food-borne E. coli bacteria and its toxins have been found in:
    • Undercooked or raw hamburgers (Contaminated meat looks and smells normal. Although the number of organisms required to cause disease is not known, it is suspected to be very small.)
    • Salami
    • Game meat
    • Alfalfa sprouts
    • Lettuce
    • Spinach
    • Lemons added to drinks in restaurants were found to be contaminated with dangerous bacteria. E coli was one of the contaminants found.(4)
    • Unpasteurized milk, apple juice, and apple cider
    • Cheese curds

  • E coli can be found and transmitted through contaminated water such as well water that is contaminated or swimming in pools contaminated by human or animal feces in underchlorinated water (2,3)

  • E coli in stools of infected persons can be passed from one person to another if hygiene is poor or handwashing is inadequate.
    • Family members and playmates of toddlers who are not potty trained are at especially high risk of becoming infected. Young children typically shed the organism in their stool for a week or two after their illness resolves.
    • Food handlers can transmit E coli through the food if proper handwashing and sanitation techniques are not followed.


What symptoms can occur from E Coli food-borne illness?

Note: The “incubation period” is the time between ingesting the E coli bacteria and the beginning of the first symptoms.



The incubation period is usually 3-4 days, but may be as short as 1 day or as long as 10 days. The symptoms often begin slowly with mild abdominal pain or diarrhea (that is not bloody). Watery diarrhea starts within a few hours and can result in dehydration from loss of fluids and electrolytes. The watery diarrhea lasts for about a day and then usually changes to bright red bloody stools. Bloody diarrhea lasts for 2 to 5 days. Fever is usually either low-grade or absent. Nausea and vomiting occasionally occurs.

The illness usually lasts an average of 5-7 days and can resolve on its own without treatment in most healthy adults.

Complications of E coli food-borne illness:

5-10% of people infected with E coli food-borne illness can develop a potentially life-threatening complication which is a form of kidney failure called HUS (hemolytic uremic syndrome). Young children and the elderly are particularly prone to this complication. In North America, HUS is the most common cause of acute kidney failure in children. HUS typically develops an average of 7 days after the first symptoms, about when the diarrhea is improving. Signs that a person might be developing HUS include decreased frequency of urination, feeling very tired, and losing pink color in cheeks and inside the lower eyelids. This life-threatening condition is usually treated in an intensive care unit of a hospital, sometimes with blood transfusions and kidney dialysis. Most with HUS recover within a few weeks, but some may die or suffer permanent damage.


Diagnosis of E coli and other food-borne illness

  Anyone who develops bloody diarrhea are advised to contact their primary care physician as soon as possible. (1,3)

Diagnosis is made through lab testing of stool specimens (feces).


Prevention of E coli and other food-borne illnesses (1)

  • WASH YOUR HANDS thoroughly after using the bathroom or changing diapers and before preparing or eating food. WASH YOUR HANDS after contact with animals or their environments (at farms, petting zoos, fairs, even your own backyard)

  • COOK meats thoroughly. Ground beef and meat that has been needle-tenderized should be cooked to a temperature of at least 160°F/70˚C. It’s best to use a thermometer, as color is not a very reliable indicator of “doneness.”

  • WASH FRUITS AND VEGETABLES thoroughly before cooking or eating raw

  • PREVENT cross contamination in food preparation areas by thoroughly washing hands, counters, cutting boards, and utensils after they touch raw meat.

  • AVOID raw milk, unpasteurized dairy products, and unpasteurized juices (like fresh apple cider).

  • AVOID swallowing water when swimming or playing in lakes, ponds, streams, swimming pools, and backyard “kiddie” pools.


1) CDC (Center for Disease Control)
2) FDA (U.S. Food and Drug Administration)
3) Food Borne Diseases from the National Institute of Allergy and Infectious Diseases
4) Lemons added to drinks in restaurants from UTube

--Written by N Thompson, RN, MSN, ARNP, Last updated March 2008

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