An outbreak of E. coli has closed the Chipotle chain in Oregon and Washington states. This strain, which produces Shiga toxin, has thus far sickened three people in Portland and 19 in western Washington, with no deaths. Cases will almost certainly rise as the investigation continues.
Most infected people develop watery or bloody diarrhea within 10 days of eating contaminated food, with 3-4 days being most common. While most cases resolve on their own, occasionally people, especially young children and the elderly, develop a kidney failure known as hemolytic uremic syndrome (HUS), and a small number might die. “Anyone who thinks they may have become ill from eating at a Chipotle restaurant in the past three weeks should consult their healthcare provider,” said State Epidemiologist Dr. Scott Lindquist. “The elderly and very young children are more likely to become severely ill from this kind of E. coli infection.”
Chipotle has had other recent problems, with earlier outbreaks in its 1,700 outlets linked to Salmonella and norovirus. This does not reflect a problem specifically with Chipotle—rather, it is their emphasis on using fresh, unprocessed ingredients.
E. coli
These bacteria are a common and normal part of our entire bacterial flora—the bacteria that inhabits our bodies and bowel and aid in digestion. Some of the strains are the “Shiga toxin-producing” E. coli, or STEC, which are the ones most likely to cause serious infection and outbreaks. E. coli O157:H7 is the most commonly reported strain linked to outbreaks here in the U.S. There are an estimated 265,000 STEC infections occur each year, with about a third due to O157:H7.
The toxigenic strains most commonly come from cattle—hence the warning to cook ground beef thoroughly. Other foods linked with E. coli outbreaks include unpasteurized (raw) milk, unpasteurized apple cider and soft cheeses made from raw milk.
One of the ironies of E. coli infections is that antibiotics can actually make the infection worse and increase the risk of kidney failure from HUS.
If diarrhea is mild and self-limited, people should let it run its course, and avoid drugs like Imodium or Lomotil. If there is bloody diarrhea, people should see their physician.
Foodborne outbreaks
Occasional outbreaks like this are pretty much unavoidable, as they are often linked to fresh fruits or vegetables—so a restaurant that focuses on fresh, unprocessed ingredients, actually is more likely to have a problem. Those pesky bacteria can hide in nooks and crevices of the produce and be nearly impossible to wash off.
To protect yourself in other ways, cook meat—especially ground beef or cuts that have been needle tenderized—to at least 160°F/70˚C. Clean cutting boards and utensils that might have become contaminated thoroughly. And the CDC advises, “avoid raw milk, unpasteurized dairy products, and unpasteurized juices (like fresh apple cider)” or swallowing water in kiddie pools, lakes, or streams, all of which can harbor other organisms as well.
It will be some time before the CDC knows for sure what caused this outbreak—first there will be careful epidemiological investigation including interviews with ill patients and restaurant workers. There will also be extensive testing of different ingredients, specifically looking for toxigenic strains. For more on how scientists trace foodborne outbreaks, see here.
You can get food poisoning anywhere. It’s important for people to not panic, and just understand this is a hazard of “healthy” eating with fresh ingredients imported from around the world.
