Editors note: On May 16, the Centers for Disease Control and Prevention said it's finally safe to eat romaine lettuce again.
At least 172 people in 32 states had been sickened after eating romaine lettuce contaminated with E. coli, according to the CDC. There has been one death reported in California since the outbreak began in early March.
The investigation into the source of the contamination of romaine lettuce is ongoing, although one farm in Yuma, Arizona has been identified. The CDC and the Food and Drug Administration are checking at least two dozen other farms as possible sources of contaminated romaine.
All of the whole head lettuce in question from Harrison Farms in Yuma was harvested during March 5-16 and is past its 21-day shelf life.
But even though the last reported illness was on April 25, the CDC is still warning consumers not to eat or buy romaine lettuce unless certain that it did not come from the Yuma growing region. It's possible for contaminated romaine lettuce to still be in homes, stores and restaurants.
"People should still not eat any romaine unless they know for sure it's not coming from Yuma," Matthew Wise of the CDC's Outbreak Response Team said.
It’s the worst outbreak of E. coli since 2006 when illnesses traced to spinach killed three and sickened more than 270. More than half of those who have become ill in the outbreak have been hospitalized, a higher than typical rate for E. coli infection, the CDC said.
“People get sick from Shiga toxin-producing E. coli an average of three to four days after swallowing the germ," the CDC said. “Most people recover within a week, but some illnesses can last longer and be more severe.”
Symptoms of Shiga toxin-producing E. coli infections can vary, but include:
- severe stomach cramps and bloody diarrhea
- a low fever, less than 101 degrees Fahrenheit
The states affected by the E. coli outbreak are:
- New Jersey
- New York
- North Dakota
- South Dakota
'Very virulent strain'
Sixty-four people out the 129 have been hospitalized, including 17 who developed kidney failure.
“This is a very virulent strain of bacteria,” James Rogers, director of food safety research and testing at Consumer Reports, told TODAY earlier. “This is nothing to play with.”
Rogers, who heads a team consisting of a food microbiologist, researchers and reporters, said it's not always easy to identify romaine in a salad or where it's from.
“Sometimes, our experts say, romaine lettuce isn’t always included as an ingredient in mixed salad bags, or the location where the lettuce is from isn’t listed,” Rogers said.
“And some people can’t really tell the difference between romaine lettuce and other types of lettuce when looking at a bag of salad,” he added.
If you have store-bought romaine lettuce at home — including whole heads and hearts of romaine, chopped romaine, and salads and salad mixes containing romaine lettuce — throw it away, the CDC said.
Even if you've eaten some of it and didn't get sick, don't eat any more of it — throw it away.
When will it be safe to eat romaine again?
It can take 2-3 weeks between the time someone gets sick from E. coli infection and the illness being confirmed as part of the outbreak, so it may be some time before the all-clear is given on romaine lettuce.