ARS Works To Enhance Food Safety

Enhancing Food Safety

Researcher Ching-Hsing Liao developed and tested a method that pits beneficial bacteria against potentially harmful ones. Bell peppers were dipped in solutions of water containing some of these beneficial bacteria. One bacterium, Pseudomonas fluorescens (Pf) 2-79, was particularly effective. 

In 2006, E. coli nearly devastated spinach growers. This year, a Salmonella scare almost ruined the season for tomato growers. With global concern over U.S. food scares, many fear that the situation has reached critical mass; but a new food safety treatment developed by Ching-Hsing Liao, a microbiologist for USDA’s Agricultural Research Service (ARS), may help.

Liao developed and tested a method that pits beneficial bacteria against potentially harmful ones. The beneficial bacteria inhibit the growth of pathogens that survive initial physical or chemical attempts to remove them from fresh produce, thus increasing the effectiveness of conventional produce sanitation methods.

“Biological treatment as demonstrated in our study can only be used as a complement to the conventional treatment,” Liao says. “Biological treatment can only suppress the growth of the pathogen but does not kill the pathogen. If the initial number of pathogens on naturally contaminated produce is high, application of biocontrol by itself would be able to eliminate or reduce the pathogen number to a non-harmful level; however it cannot replace conventional chemical or physical treatments.”

Liao identified three beneficial antagonists for use in food safety intervention. He dipped bell peppers in solutions of water containing beneficial antagonists and examined the effect on surface pathogens including Salmonella and E. coli.

An Effective Solution

One bacterium, Pseudomonas fluorescens (Pf) 2-79, was particularly effective. Dipping peppers in a Pf 2-79 solution for two minutes halted pathogen multiplication almost entirely.

“Conventional treatment either by chemicals or physical forces can only reduce 90% to 99% of the pathogens on produce,” Liao says. “Pathogens that survive the treatment can renew the growth on produce to a level capable of causing illness. If beneficial bacteria or biological control agents are applied following chemical or physical treatment, they will suppress the growth of survivor pathogens.”

On untreated peppers, pathogen populations multiplied 100,000 times when stored at 68°F for two days, but treating peppers with Pf 2-79 suppressed pathogen growth.

“Since the number of Pf 2-49 introduced onto produce is at a level much higher than the number of pathogen on naturally contaminated produce or on produce that has received other intervention treatment, robust proliferation of Pf 2-79 on inoculated produce is expected to deplete all the space or nutrients required for the growth of pathogens, or competitive exclusion,” says Liao.

The Pf 2-79 dip also suppressed the growth of spoilage or soft-rotting bacteria on bell pepper and reduced the incidence of soft rot, which indicates the treatment would not only improve the safety but also the quality of produce, according to Liao.

Because Pf 2-79 is easy to grow, the cost would be affordable once Liao and his colleagues can prove the economic benefit, he says. The treatment would be best done at produce packaging or processing plants by adding powder or liquid form of Pf 2-79 directly into a water wash tank or spraying produce with the solution, according to Liao. A regulatory approval through FDA or EPA may be required before the strain of Pf 2-79 can be used for field and commercial testing, he says.

Liao and his colleagues plan to validate the research on a larger scale, as well as identify additional bacterial strains that could be used with Pf 2-79 to further improve produce safety and quality.

“We are in the process of evaluating if mass application of Pf 2-79 would cause any sensory or flavor/aroma change on treated produce, although no indication of such undesirable effect has been observed so far,” Liao says.

Leave a Reply

Featured Stories

All Vegetables Stories >All Fruits Stories >All Nuts Stories >All Citrus Stories >

The Latest

CitrusBorder Crisis Not Helping Farmers
August 19, 2014
As thousands cross into the U.S. seeking refuge, calls for ag labor reform are lost in the uproar. Read More
Cucurbits24 Sweet Watermelon Varieties [Slideshow]
August 19, 2014
Browse the slideshow below for information on 24 watermelon varieties from the nation’s leading seed breeders and distributors. Read More
FruitsHandheld Produce Quality Meter Debuts At 2014 Internati…
August 19, 2014
Researchers to present data measuring dry matter, color, and sugar content of cherries and other product pre- and postharvest. Read More
GrapesNew York State Assists Grape Growers Hit By Harsh Winte…
August 19, 2014
State to open winegrape market to grapes grown outside the state. Read More
FruitsEuropean Fruit And Vegetable Growers Hit By Russian Ban…
August 19, 2014
Angry at European Union/United States sanctions over Ukraine, Russia has banned many food imports. Read More
Apple Grower of the Year
Apple Grower of the YearGet The Latest News On The Nation’s Apple Crop
August 19, 2014
American and Western Fruit Grower editors will be tweeting in real time this week from the Apple Crop Outlook & Marketing Conference. Read More
OrangesSour Forecast For 2014-2015 Florida Orange Crop
August 18, 2014
Paltry prediction signals lowest output in 50 years. Read More
Crop Protection
Crop ProtectionBioConsortia Inc. Bolsters Executive Team
August 18, 2014
Industry veterans Christina Huben and Dr. Susan Turner bring experience to plant biotechnology firm. Read More
Stone Fruit
Stone Fruit‘Ladderless’ Peach, Nectarine Orchards Explored
August 15, 2014
University of California researchers explore the concept of so-called pedestrian orchards. Read More
Farm Management
CitrusU.S. Sugar Buying South Florida Sugar Cane And Vegetabl…
August 15, 2014
Purported deal worth $100 million to purchase farmland and assets of Knight Management Inc. Read More
Farm Management
CitrusFlorida’s Future Farming Leaders Dig Up Knowledge…
August 15, 2014
Class 3 of FFVA's Emerging Leader Development Program learn a lot from road trip to California's Salinas Valley. Read More
CitrusWater Bond Will Appear On California Ballot
August 14, 2014
Voters will decide if thirsty state will spend $7.5 billion, including $2.7 billion for storage. Read More
BerriesFamiliar Face Settles In As New Florida Strawberry Asso…
August 14, 2014
Kenneth Parker’s deep roots in the community and knowledge of production challenges make a good combination for executive director role. Read More
Insect & Disease Update
Insect & Disease UpdateIs There Light At The End Of The Tunnel For Florida Cit…
August 14, 2014
Time is of the essence in the race to beat greening. Read More
Insect & Disease Update
Insect & Disease UpdateCoca-Cola Shares Additional $1.5 Million To Fight Citru…
August 14, 2014
Grant to help UF/IFAS researchers work toward a solution for devastating disease. Read More
Farm Management
CitrusU.S. Fall Weather Outlook Foresees Wild Ride
August 14, 2014
From continued drought in the West, to a possible early Polar Vortex visit in the East, forecasters are predicting an active autumn. Read More
Apples & Pears
Apples & PearsGrower Tells Consumers Where Their Pears Come From
August 13, 2014
Washington’s Stemilt Growers introduces Rushing Rivers as its new pear label. Read More
Apples & Pears
Apples & PearsUSApple Takes First Place At Agricultural Editors’ Aw…
August 13, 2014
Organization is honored for web presence and healthy eating campaign. Read More