June 19, 2008 — vol. 43, no 45
Why it takes so long to trace a bad tomato
WASHINGTON — Food and Drug Administration (FDA) detectives had a hot lead, narrowing down on a grower who just might have supplied salmonella-tainted tomatoes. Then the patient changed her story: She had eaten a round tomato, not a Roma one after all.
“We basically had to throw it all out and start over,” says Dr. David Acheson, the agency’s food safety chief.
Why is it taking so long to find the source of those bad tomatoes? It largely boils down to the frailty of human memory and the mysteries of the tomato bin.
Unlike many other foods, tomatoes don’t come with bar codes that let investigators quickly track their suppliers. Consumers seldom even know in what part of the world they were grown.
Moreover, it can take two to three weeks between when someone ate a tainted tomato, got sick, got diagnosed and health authorities complete testing showing it’s the outbreak strain.
And that’s if people bother going to the doctor. Few do. A common estimate is that there are 40 cases of salmonella for every one reported to the health authorities, warns Caroline Smith DeWaal, food safety director at the Center for Science in the Public Interest.
Do the math — 228 officially listed illnesses in 23 states — and it’s clear that “this is a very large nationwide outbreak,” she says.
Do some more math: The shelf life of tomatoes from the time they’re picked is three to four weeks. The earliest known salmonella case was April 10, and the latest June 1. So while it’s not clear that all the bad tomatoes are off the market, most illnesses struck in May, and no culprit tomatoes have been found sitting in anyone’s refrigerator.
Contrast tomatoes to the 2006 outbreak of E. coli in spinach. A supplier began recalls within days of the FDA’s warning. About two weeks later, the mystery was solved.
The helpful difference: The raw spinach came in bags that some patients still had in the refrigerator, bearing UPC codes that led investigators to a supplier and eventually to the exact field that had been contaminated by wild boars.
Three weeks into the salmonella probe, health authorities learned there was an outbreak on May 23, although tomatoes didn’t become a suspect until May 31; authorities had run into a number of dead ends, like the woman who didn’t really remember what she ate.
Enough people did remember what they ate for authorities to know that the culprit had to be a raw red plum, red Roma or red round tomatoes. It has been proven easier to rule a tomato-growing region innocent than guilty. Simply by using harvest and sales records, the FDA has cleared tomatoes from more than 30 states and countries — check www.fda.gov for an updated list.
(p2)| Jun 19 7:47am by Just me [66.117.243.242] | ||
|
||
related CONTENT
FDA updates on salmonella outbreak in tomatoes
This Food and Drug Administration resource page provides readers with breaking information on the outbreak, answers to frequently asked questions, consumer health information, news on what the agency is doing and more. More »
FDA: Part of Mexico cleared in salmonella probe
Baja California has been cleared of suspicion in the outbreak of salmonella-tainted tomatoes, which U.S. officials said Monday now has sickened 277 people. More »
Taco Bell, Wendy’s starting to use tomatoes again
They were two of many national restaurant chains that stopped serving tomatoes earlier this month amid a multistate salmonella outbreak linked to raw tomatoes, although there was no connection to the restaurants. More »
