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Shiga Toxin-Producing E. coli & Food Safety

Family eating at outdoor restaurantAlthough most kinds of E. coli are harmless, others can make you sick. Learn about E. coli and what you can do to help lower the risk of infection.

What are Escherichia coli?

Escherichia coli  (abbreviated as E. coli) are bacteria found in the environment, foods, and intestines of people and animals.

Most E. coli are harmless and actually are an important part of a healthy human intestinal tract. However, some E. coli can cause diarrhea, urinary tract infections, respiratory illness, bloodstream infections, and other illnesses. The types of E. coli that can cause illness can be transmitted through contaminated water or food, or through contact with animals or people.

Quick Guide to Understanding E. coli

There are 6 different types of E. coli that cause diarrhea.

Some E. coli cause disease by making a toxin called Shiga toxin. The bacteria that make these toxins are called "Shiga toxin-producing E. coli," or "STEC," for short.

The most commonly identified STEC in North America is E. coli O157:H7.

Other E. coli in the STEC group, including O145, are sometimes called "non-O157 STECs."

Learn more >

What are Shiga toxin-producing E. coli?

One particular type of E. coli causes disease by making a toxin called Shiga toxin. The bacteria that make these toxins are called "Shiga toxin-producing E. coli," or STEC, for short. STEC is often sub-divided into two categories: E.coli O157 and non-O157 STECs.

  • Most common type of STEC: The most commonly identified STEC infections in North America are E. coli O157:H7 (often shortened to E. coli O157 or even just O157). When you hear news reports about outbreaks of E. coli infections, they are usually talking about E. coli O157.
  • Other types of STEC: Other types of E. coli in the STEC pathotype are sometimes called "non-O157 STECs."

Who gets STEC infections?

People of any age can become infected. Very young children are more likely than others to develop severe illness and a complication called hemolytic uremic syndrome, but even healthy older children and adults can become seriously ill.

What are the symptoms of STEC infections?

The symptoms of STEC infections vary for each person but often include severe stomach cramps, diarrhea (often bloody), and vomiting. If there is fever, it usually is not very high (less than 101˚F). Most people get better within 5–7 days. Some infections are very mild, but others are severe or even life-threatening.

Did You Know?

Lab technician working

Newer and faster diagnostic technology called culture independent diagnostic tests (CIDTs) aids in diagnosing non-O157 STEC infections. However, CIDTs present some challenges:

  • CIDTS may affect our ability to track foodborne illness trends. Learn more >
  • CIDTs may affect our ability to identify outbreaks. Learn more >

Hamburger and French fries

Problem: One in four burgers turns brown before it has reached the safe internal temperature of 160°F (according to USDA Color of Cooked Ground Beef as It Relates to Doneness).

Solution: Use a food thermometer.

Around 5–10% of those who are diagnosed with E. coli O157 infection develop a potentially life-threatening complication known as hemolytic uremic syndrome (HUS). Clues that a person is developing HUS include decreased frequency of urination, feeling very tired, and losing pink color in cheeks and inside the lower eyelids. Persons with HUS should be hospitalized because their kidneys may stop working and they may develop other serious problems. Most persons with HUS recover within a few weeks, but some suffer permanent damage or die.

Contact your healthcare provider if you have diarrhea that lasts for more than 3 days, or is accompanied by high fever, blood in the stool, or so much vomiting that you cannot keep liquids down and you pass very little urine.

How can STEC infections be prevented?

  • Know your risk of food poisoning. People at higher risk for foodborne illness are pregnant women, newborns, children, older adults, and those with weak immune systems.
  • Practice proper hygiene, especially good hand washing.
    • Wash your hands thoroughly after using the bathroom, changing diapers, and before preparing or eating food.
    • Wash your hands thoroughly after contact with animals or their environments (at farms, petting zoos, fairs, even your own backyard).
    • Wash your hands thoroughly before preparing and feeding bottles or foods to an infant or toddler, before touching an infant or toddler's mouth, and before touching pacifiers or other things that go into an infant or toddler's mouth.
    • Keep all objects that enter infants' and toddlers' mouths (such as pacifiers and teethers) clean.
    • If soap and water aren't available, use an alcohol-based hand sanitizer. These alcohol-based products can quickly reduce the number of germs on hands in some situations, but they are not a substitute for washing with soap and running water.
  • Follow clean, separate, cook, chill guidelines, which can be found at FoodSafety.gov.
  • Cook meats thoroughly. Beef steaks and roasts (including those that have been mechanical/needle tenderized) should be cooked to a minimum internal temperature of 145°F (62.6˚C) and allowed to rest for at least 3 minutes for safety and quality. Ground beef products should be cooked to a minimum internal temperature of 160°F (70˚C). Always use a food thermometer to verify the temperature because the color of meat is not a reliable indicator that the meat has been cooked to the safe internal temperature.
  • Prevent cross-contamination in food preparation areas by thoroughly washing hands, counters, cutting boards, and utensils after they touch raw meat.
  • Avoid consuming raw milk, unpasteurized dairy products, and unpasteurized juices (such as fresh apple cider).
  • Avoid swallowing water when swimming and when playing in lakes, ponds, streams, swimming pools, and backyard "kiddie" pools.
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