Newly discovered bacterium blocks salmonella

Salmonella -- the foodborne illness that, according to the CDC, is responsible for some 23,000 hospitalizations and 450 deaths every year -- doesn't just arrive via undercooked meats. Just as often, it travels with crates of contaminated fruits and vegetables: lettuce, melons, tomatoes, you name it. That's why scientists with the U.S. Food and Drug Administration are excited about a newly identified benign bacterium that shows real promise in thwarting salmonella as it attempts to colonize raw tomatoes. Since 2000, more than 2,000 people in the U.S. have fallen ill as result salmonella-infected tomatoes. "The conditions in which tomatoes thrive are also the conditions in which Salmonella thrives," FDA researcher Eric W. Brown recently explained. "But we knew that if we could block salmonella from infecting the tomato plant, we could reduce its risk of infecting the person who eats the tomato." Luckily for scientists -- and tomato lovers -- the same conditions that allow salmonella to thrive also enable the growth of many kinds of benign bacterium, those that aren't harmful to human health. Researchers knew they just need to find a strain that outcompeted salmonella for real estate. They succeeded, having isolated Paenibacillus alvei. "We hypothesized that such an organism could be found that possessed the ability to outcompete or chemically destroy Salmonella," says co-researcher Jie Zheng. "After screening many hundreds of potential biocontrol strains of bacteria that were isolated from farms and natural environments in the Mid-Atlantic region, we found about 10 isolates of bacteria representing very different genera and species that could curb the growth and/or destroy Salmonella in our test assays." Brown and Zheng's important research will be detailed in the July edition of the journal Applied and Environmental Microbiology. A manuscript is currently available online.