Tomato turf wars: Benign bug bests salmonella; tomato eaters win

May 05, 2014

Scientists from the U.S. Food and Drug Administration (FDA) have identified a benign bacterium that shows promise in blocking Salmonella from colonizing raw tomatoes. Their research is published ahead of print in the journal Applied and Environmental Microbiology.

When applied to Salmonella-contaminated tomato plants in a field study, the bacterium, known as Paenibacillus alvei, significantly reduced the concentration of the pathogen compared to controls.

Outbreaks of Salmonella traced to raw tomatoes have sickened nearly 2,000 people in the US from 2000-2010, killing three. Since the millennium, this pathogen has caused 12 multistate outbreaks of food-borne illness—more than one each year. It was this carnage that provided the impetus for the study, according to corresponding author Jie Zheng, of the FDA.

"The conditions in which tomatoes thrive are also the conditions in which Salmonella thrives," says coauthor Eric W. Brown, also of FDA, "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."

The logic behind the work is simple. Many innocuous bacterial species thrive within the tomato-growing environment.

"We hypothesized that such an organism could be found that possessed the ability to outcompete or chemically destroy Salmonella," says 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."

Many of these were as pathogenic to humans as is Salmonella, but two isolates, belonging to the environmentally friendly species, P. alvei, strongly inhibited growth of Salmonella.

"This bacterium also has no known history of human pathology, making it a great candidate as a ," says Zheng.

"While farmers and agricultural scientists have long used microbes to prevent plant diseases, we now have the opportunity to add a naturally-occurring microbe to a crop in the field with the goal of preventing human disease," says Zheng. "Our ambitions are now to extend this microbial approach to cantaloupe, leafy greens, and other crops that have lately been responsible for outbreaks of food-borne Salmonella and E. coli."

Explore further: Salmonella decline seen in food poisoning report

More information: The manuscript can be found online. The final version of the article is scheduled for the July 2014 issue of Applied and Environmental Microbiology.

add to favorites email to friend print save as pdf

Related Stories

Do people and pigs share salmonella strains?

Apr 03, 2014

If antimicrobial-resistant Salmonella is showing up in pigs, then are bacon-loving people also at risk? In his latest research, NC State population health and pathobiology professor Sid Thakur looks at serotypes, ...

Salmonella at Ind. farm matches outbreak strain

Aug 28, 2012

(AP)—The Food and Drug Administration says salmonella found at a cantaloupe farm in southwestern Indiana matches the "DNA fingerprint" of the salmonella responsible for a deadly outbreak that sickened people in 21 states.

FDA: Farm tied to salmonella outbreak was unclean

Oct 03, 2012

(AP)—A federal inspector found two strains of salmonella and unclean conditions at an Indiana cantaloupe farm's fruit-packing plant during visits following a deadly outbreak linked to its melons.

Recommended for you

Top Japan lab dismisses ground-breaking stem cell study

Dec 26, 2014

Japan's top research institute on Friday hammered the final nail in the coffin of what was once billed as a ground-breaking stem cell study, dismissing it as flawed and saying the work could have been fabricated.

Research sheds light on what causes cells to divide

Dec 24, 2014

When a rapidly-growing cell divides into two smaller cells, what triggers the split? Is it the size the growing cell eventually reaches? Or is the real trigger the time period over which the cell keeps growing ...

Locking mechanism found for 'scissors' that cut DNA

Dec 24, 2014

Researchers at Johns Hopkins have discovered what keeps an enzyme from becoming overzealous in its clipping of DNA. Since controlled clipping is required for the production of specialized immune system proteins, ...

Scrapie could breach the species barrier

Dec 24, 2014

INRA scientists have shown for the first time that the pathogens responsible for scrapie in small ruminants (prions) have the potential to convert the human prion protein from a healthy state to a pathological ...

Extracting bioactive compounds from marine microalgae

Dec 24, 2014

Microalgae can produce high value health compounds like omega-3s , traditionally sourced from fish. With declining fish stocks, an alternative source is imperative. Published in the Pertanika Journal of Tr ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.