In a sweeping alert, federal health officials warned people not to eat romaine lettuce anywhere in the country, after 32 people in 11 states fell sick with a virulent form of E. coli, a bacteria blamed for a number of food-borne outbreaks in recent years.
The notice, issued Tuesday afternoon by the Centers for Disease Control and Prevention, said consumers should not buy or eat any kind of romaine, whether chopped or whole, and restaurants should stop serving it. Anyone who has romaine, the health agency said, should throw it out.
Officials said such extraordinary measures were necessary while they track down the source of the contamination. Investigators believe the tainted lettuce was grown or processed in Canada or the United States, but they do not know where.
The outbreak was first identified on October 8 and has led to the hospitalization of 13 people, including one person who developed kidney failure. So far no deaths have been reported. Roughly a third of the cases were reported in California; the others are concentrated in the northeast and in the Great Lakes region.
Another 18 people have been sickened in the Canadian provinces of Ontario and Quebec.
“Consumers who have any type of romaine lettuce in their home should not eat it and should throw it away, even if some of it was eaten and no one has gotten sick,” the C.D.C. said in a statement. “If you do not know if the lettuce is romaine or whether a salad mix contains romaine, do not eat it and throw it away. Wash and sanitize drawers or shelves in refrigerators where romaine was stored.”
Health officials said the current cases are unrelated to an E. coli outbreak earlier this year that killed five people and sickened 200. Investigators later traced that bacteria to a tainted drainage canal near a lettuce farm in Arizona.
The strain of E. coli associated with the current outbreak has been identified as Shiga toxin-producing Escherichia coli O157:H7. Officials say the same strain was involved in a different E. coli outbreak in 2017 that infected 25 people in 15 states. Investigators blamed that flare-up on leafy greens, but they were unable to identify the specific type of lettuce or the source.
