RENEE MONTAGNE, Host:
Health officials are trying to trace the source of that salmonella contamination we've been reporting on. At least 145 people who've eaten tomatoes have fallen ill. NPR's Allison Aubrey reports on why the Food and Drug Administration is urging consumers to avoid Roma Plum and red round tomatoes.
ALLISON AUBREY: If you're thinking that almost all tomatoes are red and round, you may be wondering if there's a safe bet at the moment. So far, what investigators know is that cherry, grape and tomatoes sold with the vines still attached have not been implicated by people who've gotten sick. And to the question can tomatoes simply be cleaned off to get rid of the salmonella bacteria, food safety expert Tom Chestnut of NSF International says not reliably.
TOM CHESTNUT: Washing of fruits and vegetables are very good means to get reduction of the bacteria that's on the outside, but it's very difficult to get a total elimination.
AUBREY: One reason is that the bacteria cling to the skin. Another is that it can get into the tomato through tiny pores in the skin. Chestnut says in packing houses, tomatoes are often submersed in chlorinated water. He explains if the rinse is too cold or the tomato's too hot, the pores can open up, and temperature can be a problem.
CHESTNUT: Because if you get too wide of a fluctuation in that, you can introduce contamination into the tomato itself.
AUBREY: Until officials figure out where the salmonella came from, consumers should eat only the cherry and grape varieties or tomatoes still on the vine. Allison Aubrey, NPR News. Transcript provided by NPR, Copyright NPR.