Dec. 7, 2015 -- Hundreds of people across the country fell ill this year in outbreaks of E. coli, as the bacteria triggered recalls of ground beef, chicken salad, bottled water, and celery, among others.
WebMD turned to experts and the CDC to shed light on where E. coli lurks and how to protect yourself.
What is E. coli exactly, and how common is it?
It's short for Escherichia coli, and it's bacteria found in the environment, foods, and both human and animal intestines. There are numerous strains and most are harmless. Those that can make you sick can cause sometimes-bloody diarrhea, urinary tract infections, respiratory illness and pneumonia, and a type of kidney failure, the CDC says.
E. coli contamination is often linked in our minds with undercooked burgers, but what other foods can it happen in?
As this year's outbreaks suggest, many other foods. Produce, unpasteurized dairy products, and apple cider are among them, says Jonathan Fielding, MD, MPH, professor of health policy and management at UCLA's Fielding School of Public Health.
Fresh produce is the leading cause of outbreaks, according to a study released Dec. 3 by the Center for Science in the Public Interest. The researchers looked at 10 years of data from outbreaks to find out which foods are most commonly linked to the problem.
Over the decade studied, fresh produce was involved in 629 outbreaks and nearly 20,000 food-borne illnesses. But the researchers added an important caveat. On a pound-for-pound basis, fresh fruits and vegetables are safer than other foods. According to CSPI experts, the risk of food-borne illness from E. coli is twice as high from chicken as from vegetables.
And pound for pound, seafood cops the No. 1 spot for the leading cause of food-borne illness, CSPI says.
How does the bacteria get into foods?
Meat can be contaminated during the slaughtering process if bacteria-laden cattle feces are present, Fielding says. Contaminated cow feces can also wash down from a field when it rains and flow into celery fields or other growing produce, he says. Milk can get contaminated when cow feces comes into direct contact with it, the CDC says. Restaurant servers who have contaminated feces and don't properly wash their hands can also spread the bacteria.
How prevalent is E. coli infection?
In a report published in May, the CDC found that the number of reported infections with the strain known as E. coli 0157, the major culprit in outbreaks, fell by about a third in 2014 compared to 2006-2008. Those numbers don't include the recent outbreaks.
"We don't know exactly because not everyone reports it," Fielding says.
According to CDC estimates, 1 in 6 people in the U.S. get sick from contaminated food each year, but that also includes contamination from organisms other than E. coli.
How sick can it make you?
"You can have the classic Montezuma's revenge type or a much more serious illness known as hemolytic uremic syndrome (HUS),” says Aaron Glatt, MD, spokesman for the Infectious Diseases Society of America.
E. coli can cause Montezuma’s revenge, or so-called travelers’ diarrhea. It can be treated with rest and drinking fluids -- but symptoms like persistent vomiting, a fever, or bloody diarrhea can be a sign you should get medical help.
HUS can lead to kidney failure, but it only affects about 10% of those who get E.coli, Fielding says. And about 1 in 10 of those who get HUS die from it, he says.
Some people -- those with weakened immune systems, children or the elderly -- can have more severe E. coli infections, according to the CDC.
What kind of medical care do you need if you’re diagnosed with E. coli?
You may be able to sit out a minor infection, as you rest and drink plenty of fluids. Typically, people get sick anywhere from 2 to 8 days after eating the contaminated food, Fielding says.
In many, the symptoms resolve in about a week, the CDC says. But if you don't feel better after that time, consider seeing a doctor, Fielding says. "In most cases, antibiotics aren't recommended," he says, as they can potentially increase the risk of complications.
Doctors also warn against the use of anti-diarrheals, as this can keep the bacteria in your system longer.
How can we lower our chances of getting sick?
It can help to choose your foods wisely, store them safely, and eat at restaurants with good practices, Fielding says.
It's crucial to avoid unpasteurized dairy foods and apple cider, he says. Also, cook beef thoroughly, to 160 degrees F.
As you shop, separate the produce from the meat. Once home, don't put meat above produce in the refrigerator, since contaminated meat juice can drip down on the produce, Fielding says.
Wash produce well. That doesn't always get rid of contamination, but it helps. Among the trickiest produce to wash are sprouts, he says, because the E. coli may lodge inside the seed.
When you prepare food, wash the cutting board, knife and cooking area soon after preparing raw meat. Better yet, use separate cutting boards for meats and vegetables, he says.
Proper hand-washing can also prevent the spread of E. coli.
Check restaurant grades if they're available. You can also go by visual inspection, Glatt says. "If the place looks filthy, turn around and go."
Don't go by price, he says. "Expensive restaurants are not necessarily any better than the fast food, relatively inexpensive food. I think it has [more] to do with the person in charge of the kitchen."