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Investigators Work To Track Down Source Of Romaine Lettuce Contamination


Grocery shoppers looking for salad today encountered some odd gaps on supermarket shelves. The hearts of romaine had disappeared - so had the bags of Caesar salad mix. That's because the Food and Drug Administration has issued a warning - throw away your romaine lettuce. It could be contaminated with poisonous E. coli bacteria. The investigators who are trying to track down the source of the contamination have the feeling they've seen this movie before, and it's driving a more aggressive government response. NPR's Dan Charles has the story.

DAN CHARLES, BYLINE: Over the past six weeks, at least 50 people in the U.S. and Canada have gone to the doctor suffering the symptoms of food poisoning. They were infected with E. coli bacteria. And most of them remembered eating romaine lettuce, which led to yesterday's warning from public health officials in both the U.S. and Canada.

And there was a detail in that announcement that really caught the attention of food safety experts. This exact strain of E. coli bacteria had turned up before. It caused a relatively small wave of illness a year ago then seemed to disappear. It got more attention in Canada than in the U.S. The Canadians thought people were getting infected from romaine lettuce. The U.S. government wasn't convinced. And now it's back. Jeff Farber, at the University of Guelph in Canada, says this almost never happens.

JEFF FARBER: We usually do not see that with - to have like a year apart - the same strain of E. coli, 1057, still hanging around.

CHARLES: And it's disturbing, he says, to think that the source of the E. coli contamination a year ago is still there, making people sick.

FARBER: It basically means they never really solved the problem of where the E. coli strain is coming from.

CHARLES: He's optimistic they'll find the source this time.

FARBER: I think it's very important that they do isolate it, so we don't have a third outbreak because then, I think, there'd be a lot of pressure to do something drastic.

CHARLES: He says he doesn't know what that something drastic might be. Lawrence Goodridge, director of the food safety program at McGill University in Montreal, says yesterday's announcement was actually a more drastic response than usual. Telling people to stop eating all romaine lettuce helps protect the public, but it also means a lot of economic damage to workers and companies that are selling healthy uncontaminated lettuce.

LAWRENCE GOODRIDGE: So there's this fine line that has to be walked by the public health officials.

CHARLES: He says, yes, it is a tiny number - 50 people sick out of hundreds of millions - but he would advise people to follow the recommendations from public health authorities.

GOODRIDGE: I'd like to say that there's no need for the public to panic, but even one case is too much.

CHARLES: And he's playing it safe, he says - no romaine for him. Dan Charles, NPR News.

(SOUNDBITE OF TURA'S "CRAZY SUMMER") Transcript provided by NPR, Copyright NPR.

Dan Charles is NPR's food and agriculture correspondent.