The restaurant chain has responded by temporarily closing 43 restaurants in the two states affected, "even though only eight restaurants have drawn concern," the company said in a statement Tuesday.
The company is also deep cleaning and sanitizing all of its restaurants in that region, as well as conducting environmental and food testing in those locations, as well as testing in its distribution centers.
"The safety of our customers and integrity of our food supply has always been our highest priority," Steve Ells, chairman and co-CEO of Chipotle, said in a statement. "We work with a number of very fresh ingredients in order to serve our customers the highest-quality, best-tasting food we can. If there are opportunities to do better, we will push ourselves to find them and enhance our already high standards for food safety. Our deepest sympathies go out to those who have been affected by this situation and it is our greatest priority to ensure the safety of all of the food we serve and maintain our customers' confidence in eating at Chipotle."
No one has died in the reported cases of infection, the Washington State Department of Health said. Seven of the Washington patients and three Oregon patients were hospitalized.
A lawsuit was filed in federal court Monday
in connection with the outbreak. Charmaine Denise Mode, a pharmacist from Kelso, Washington, ate at a Chipotle restaurant in Vancouver, Washington, on October 21 and started feeling nauseated four days later with "severe diarrhea," according to the lawsuit against Chipotle.
"The next day, the diarrhea became bloody and far more intense," the suit said. She went to the hospital, where she "endured a painful rectal examination," said the suit.
The next day, local health officials linked her case to the Chipotle outbreak, according to the suit, which seeks damages of at least $75,000.
Chipotle did not immediately comment on the lawsuit.
Chris Collins of Portland, Oregon, went to an urgent care center two days after eating at a Chipotle restaurant. "I've never gotten sick like this," he told CNN affiliate KATU
. "The excruciating pain in my abdomen was something I've never experienced. It feels like your guts are being ripped out."
The urgent care center sent him to a hospital emergency room.
Contamination source still undetermined
The source of contamination has yet to be exactly determined, and Chipotle is working with health departments and federal agencies such as the Centers for Disease Control and Prevention
and the Food and Drug Administration
to help determine the cause of the cases.
On Tuesday, Dr. Tom Frieden, director of the CDC, said the closing down the Chipotle locations was the right thing to do. "[It's] always better to take broad action than narrow it down," he said. "From what we understand so far, they are being very responsible in their actions in response to the cases that have been reported. "
No exact source has yet been identified in this outbreak, but Dr. Kathleen Gensheimer, the FDA's chief medical officer and director of outbreak response, said Chipotle "is sharing all of their records with us, working with us in any way possible to give us information."
Dr. Jeff Duchin, a health officer in King County in Washington, said that these investigations are "really hard" to do since there is overlap in the ingredients used in the different menu items. He's hoping the environmental testing can pinpoint the specific item causing the outbreak. A number of produce items and a few spices have been sent to the lab for testing.
This year, Chipotle also experienced a salmonella outbreak
associated with tomatoes, as well as a Norovirus outbreak
associated with one of its stores.
"We have seen them associated with clusters this past year, and when the smoke dies down, Chipotle has said they are interested in coming to FDA to discuss what practices might be contributing to these events," Gensheimer said.
More than 20 outbreaks since 2007
Infections with Escherichia coli can cause severe stomach cramps, vomiting and diarrhea which is often bloody. Fever is usually low, if at all present, according to
the CDC. Infections can range from mild to life-threatening.
E. coli bacteria are commonly found in human and animal intestines and are a key component of healthy digestion. Most strains are harmless but some are not, according to the CDC. "Infections start ... when you get tiny (usually invisible) amounts of human or animal feces in your mouth," it says.
This happens surprisingly often, the CDC says, and many times no infection results.
Common sources of infection are human and animal contact in the farming industry. In April, at least 25 people became ill with E. coli infections after visiting a dairy fair in Washington state.
But harmful E. coli can also make their way into food ingredients. Food handlers carrying harmful E. coli can pass the bacteria on by not thoroughly washing their hands before performing their work.
The CDC has investigated more than 20 major E. coli outbreaks since 2007. Other common foodborne ailments are caused by listeria and salmonella bacteria.