Update: On June 28, 2018, the Centers for Disease Control and Prevention declared this E. coli outbreak officially over.

Update: On Apr. 16, 2018, Consumer Reports advised against eating romaine lettuce again after an E. coli outbreak sickened 35 people across the U.S.

Update: On Jan. 25, 2018, U.S. food safety and health officials declared an end to the E. coli outbreak linked to leafy greens. In light of this development, Consumer Reports is no longer recommending that consumers avoid romaine lettuce. For more information, read our update.

Over the past seven weeks, 59 people in the U.S. and Canada have become ill from a dangerous strain of E. coli bacteria, likely from eating romaine lettuce. In the U.S., the infections have occurred in 13 states (California, Connecticut, Illinois, Indiana, Michigan, Nebraska, New Hampshire, New York, Ohio, Pennsylvania, Virginia, Vermont, and Washington state). Five people in the U.S. have been hospitalized and one has died, according to the Centers for Disease Control and Prevention (CDC). There has also been one death in Canada.

Canadian health authorities identified romaine lettuce as the source of the outbreak in Canada, and are advising people in the country’s eastern provinces to consider eating other types of salad greens until further notice. Some Canadian stores have pulled romaine off of their store shelves. 

Today, the Centers for Disease Control confirmed for the first time to Consumer Reports that the strain of E. coli detected in the U.S. is "a virtual genetic match" with the one that has caused illnesses in Canada.

Matthew Wise, M.P.H., Ph.D., head of the CDC's Outbreak Response Team, says that in spite of this finding, investigators are still not sure that romaine lettuce is the cause of the E. coli outbreak in the U.S. "We are looking at romaine and other leafy greens," says Wise. "[The Canadians] gave us a good starting point." He says they hope to conclude their investigation within the next two weeks. 

In spite of Canada's advisory to "consider consuming other types of lettuce, instead of romaine," U.S. government health officials have stopped short of recommending people avoid romaine lettuce or any other food. 

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The strain of E. coli (0157:H7) found in both the U.S. and Canada produces a toxin that in some cases can lead to serious illness, kidney failure, and even death.

That’s why Consumer Reports' food safety experts are advising that consumers stop eating romaine lettuce until the cause of the outbreak is identified and the offending product is removed from store shelves.

“Even though we can’t say with 100 percent certainty that romaine lettuce is the cause of the E. coli outbreak in the U.S., a greater degree of caution is appropriate given that lettuce is almost always consumed raw,” says James Rogers, Ph.D., director of Food Safety and Research at Consumer Reports.

While anyone can get sick if they are infected with E. coli 0157:H7, young children, the elderly, and anyone who has a condition (such as cancer or diabetes) that weakens the immune system are at greater risk. “People in these groups should be particularly vigilant about avoiding romaine lettuce,” says Rogers. 

What U.S. Health Authorities Are Doing

In addition to the CDC, the Food and Drug Administration is investigating the E. coli infections in the U.S. At this point, neither agency claims to have enough information to recommend Americans avoid any particular food. 

More Information On Food Safety

“There is not enough epidemiologic evidence at this time to indicate a specific source of the illnesses in the United States,” says Brittany Behm, MPH, a CDC spokesperson. “Although some sick people reported eating romaine lettuce, preliminary data available at this time shows they were not more likely than healthy people to have eaten romaine, based on a CDC food consumption survey.” Health officials, Behm says, take action when there is clear and convincing information linking illness to a contaminated food.

“The FDA should follow the lead of the Canadian government and immediately warn the public about this risk,“ says Jean Halloran, director of Food Policy Initiatives at Consumers Union, the policy and mobilization division of Consumer Reports.

“The available data strongly suggest that romaine lettuce is the source of the U.S. outbreak," she says. "If so, and people aren’t warned, more may get sick.”

Under the Food Safety Modernization Act, the FDA has the authority to recall a hazardous food if a company fails to do so, but in this case health authorities have not yet identified the specific source of the outbreak. However, nothing prohibits health authorities from issuing a general warning in situations like this one with romaine lettuce.

And even if there was a product to recall, Halloran notes that it may take awhile before there is any company or FDA action. According to a report released in December by the Inspector General’s office at the U.S. Department of Health and Human Services, the FDA has at times been slow to secure recalls, which may be voluntary or mandatory. FDA Commissioner Scott Gottlieb said in a statement that the report raised some "signficant concerns" and that while the FDA has addressed many of the issues raised in the report, "we still have more work to do."  

“FDA needs to act promptly to protect consumers' health. People could eat a lot of potentially contaminated romaine while waiting for a company recall or for the CDC and FDA to identify the specific source of the outbreak and order a mandatory recall of the affected products,” Halloran explains.

our petition to ask the FDA to advise consumers on how to protect themselves from the E. coli outbreak.

How Lettuce Becomes Tainted

Outbreaks of toxin-producing E. coli are more typically linked to beef (the bacteria can get into the meat during slaughter and processing), especially ground beef, but infections from produce are not unheard of. Leafy greens, including romaine lettuce, were the cause of outbreaks from E. coli 0157:H7 in 2006, 2011, 2012, and 2013.

Vegetables can be contaminated if animal feces are in the field or in irrigation or washing water,” says Rogers, “The bacteria can also be transmitted if a person who is carrying the bacteria doesn’t wash his or her hands after using the bathroom and then processes or prepares food.”

Washing your greens is a good idea, but won’t necessarily get rid of dangerous E. coli, which can cling to nooks and crannies in the leaves, Rogers notes.

What You Should Do Now

Neither the CDC or Canadian health officials have provided any information on where the romaine lettuce potentially involved in the illnesses was grown or processed, so for now, assume that any romaine lettuce, even when sold in bags and packages, could possibly be contaminated, Rogers says. Don’t buy romaine lettuce and don’t use any that you may have in your refrigerator until there is more information on the source of contamination. In their warning, the Canadian health officials noted that romaine lettuce can have a shelf life of up to five weeks, so lettuce you purchased a few weeks ago could still be contaminated. Check salad blends and mixes, too, and avoid those that contain romaine.

Symptoms of infection with E. coli 0157:H7 are severe stomach cramps, diarrhea (often bloody), and vomiting. Some people may have a slight fever.

The symptoms typically start 1 to 3 days after eating a contaminated food, but may occur as late as 10 days afterwards. The CDC recommends seeing a doctor if you have a high fever, bloody diarrhea, or severe vomiting, or if diarrhea lasts longer than 3 days.

About 5 to 10 percent of people infected with E. coli 0157:H7 may develop hemolytic uremic syndrome, a serious condition which affects the blood vessels and can lead to kidney failure and death. This condition (which includes symptoms such as extreme fatigue, decreased urination and paleness in the cheeks and under the eyes) typically occurs about 7 days after E. coli symptoms first start.