FDA's tomato team fights Salmonella ntamination

From www.foodsafetynews.com:

Photo: Research microbiologist Rebecca Bell observes tomatoes suspended in a plastic bag of a liquid containing nutrients that make it an ideal environment for growing bacteria. Photo courtesy of FDA’s flickr.

A fresh tomato is more than just a tasty addition to a sandwich or salad.

To scientists at the Food and Drug Administration (FDA), the tomato is an enigma and the focus of a group of researchers nicknamed “Team Tomato.”

The mystery of the tomato has to do with its vulnerability to contamination by Salmonella, a bacterium that is a common cause of foodborne illness.

From 1973 to 2010, there were 15 multistate outbreaks of illnesses attributed to Salmonella contamination of raw tomatoes, with 12 of these outbreaks taking place since 2000. They resulted in almost 2,000 confirmed illnesses and three deaths, with states in the eastern U.S. hardest hit.

“The conditions in which tomatoes thrive are also the conditions in which Salmonella thrive,” says Eric Brown, Ph.D., director of FDA’s Division of Microbiology. “But the tomato always presented an extra challenge because it is so short-lived. By the time it looked like contaminated tomatoes could be causing illnesses, the harvest would be gone.”

So FDA’s focus has changed over the last decade to reducing contamination early in tomato production. Says Brown, “The question was clear: What can we do to intervene and prevent this contamination from happening in the first place?”

New Research

FDA microbiologist Rebecca Bell, Ph.D., lead researcher on the tomato team, says the agency studies tomatoes on an experimental farm at Virginia Tech’s Agriculture and Research Extension Center (AREC). This land is next to farms that have been the source of Salmonella contamination, giving the researchers access to real conditions and real threats.

The researchers collected more than a thousand bacteria in the soil and water in search of a natural enemy of Salmonella and they found one—a bacterium called Paenibacillus, which is benign to humans but kills Salmonella. FDA will be working with the Environmental Protection Agency (EPA) to facilitate the development of an organic treatment containing Paenibacillus that would kill Salmonella and other harmful organisms.

Bell says this will be a particularly valuable Salmonella-fighting tool in the mid-Atlantic region, where farmers often fumigate six inches down into the soil to kill harmful bacteria. Their methods for doing so may, ironically, create more opportunities for enteric pathogens (gastrointestinal organisms spread by contamination of food), such as Salmonella, to colonize in the roots of the tomato plants.

Read the rest of the story here.