FEATURE | Posted Dec. 11, 2015

What is E. coli?

What you and your family need to know

Photograph of Dr. Dean Blumberg © UC Regents
Dean Blumberg, chief of pediatric infectious diseases at UC Davis Children’s Hospital, answers those questions and more.

With the recent outbreak of E. coli at Chipotle restaurants and Costco stores, consumers might be wondering what exactly E. coli is, who is at risk and how to prevent an E. coli infection.

What is E. coli?

Escherichia coli (E. coli) is a common bacteria. There are several different strains of E. coli. Some cause no harm, while others are common causes of travelers’ diarrhea. And then there are strains that are worrisome because of the dangerous toxins they produce.

People may carry E. coli, animals can carry it, and it has been linked to acute illnesses. It can contaminate food and be transmitted person-to-person, for example, in a daycare environment. It is usually spread by consuming invisible amounts of human or animal feces – which happens more frequently than we’d like to imagine.

Where is E. coli found?

E. coli exposures have been linked to the consumption of contaminated food, consumption of unpasteurized (raw) milk, and contact with animals, including petting zoos. Animals may carry it and then contaminate other foods that people eat.

High risk foods E. coli can be found in include:

  • Unpasteurized (raw) milk, or cheeses made from raw milk
  • Undercooked hamburger
  • Contaminated pieces of raw produce, including lettuce, sprouts, celery, onions, apples, etc.

Who is most at risk for becoming ill with E. coli?

Everybody can be at risk for getting infected. Symptoms can show up anytime between one and 10 days after exposure. Symptoms can include abdominal cramps, diarrhea, sometimes with blood in the stool. E. coli infections usually get better within a week.

However, there is a risk of developing a complication known as hemolytic uremic syndrome (HUS), a type of kidney failure.

The following groups are at higher risk of HUS:

  • Children under age 5
  • Anyone over 65 years of age
  • Those with a compromised immune system

How common is E. coli?

E. coli is not terribly common, but there are outbreaks. E. coli is scary though because of the risk of kidney damage,

What should someone with symptoms do?

I would advise anybody that has blood in their stool to contact their health care provider. If they have a fever associated with the diarrhea, any kind of decreased urination or an increase in bruises or bleeding, it may indicate the onset of HUS and one should seek medical attention immediately.

If someone does not have any of the aforementioned symptoms, and has a mild illness with vomiting and diarrhea (with no blood in the stool) and can maintain hydration, the illness is likely to run its course.

How can people avoid getting E. coli?

Follow safe food handling and cooking recommendations:

  • 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 (farms, petting zoos, fairs, or your own backyard).
  • Cook meat thoroughly, to 160 degrees Fahrenheit.
  • Avoid raw milk, unpasteurized juices and dairy products.
  • Thoroughly clean all utensils and preparation surfaces.

The safe food handling recommendations are not just applicable for E. coli. Listeria can be found in different foods, like dairy products and soft cheeses, but the same precautions apply. 

Related information: