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
Apples & PearsPennsylvania Congressman Supports CIDER Act
August 31, 2015
Freshman Congressman Ryan Costello (PA-06) spent a recent afternoon at Frecon Farms in Boyertown, PA, to tout the CIDER Act, Read More
Oriental Fruit fly
CitrusExotic Fruit Flies Invade South Florida
August 31, 2015
Efforts are under way to eradicate pest that attacks more than 230 different fruits, vegetables, and nuts. Read More
Business PlanningBe Food Safety Recall-Ready [Opinion]
August 31, 2015
No one ever wants to make someone sick after consuming fresh produce, but in spite of the protocols in place, recallls happen and you must be prepared. Read More
Crop ProtectionSustainable Options For Controlling Stink Bug In Vegetables
August 31, 2015
A researcher from Rutgers University offers pointers to help you control this pest of fruits and vegetables. Read More
CitrusNominations Open For Next Class Of Florida Citrus Hall Of Famers
August 31, 2015
Inductees to be honored during the 54th annual Citrus Celebration Luncheon. Read More
CitrusWhole-Farm Revenue Protection Insurance To Be Available In 2016
August 31, 2015
USDA offers greater flexibility for beginning, organic and fruit and vegetable growers. Read More
Cucurbits8 Must-Have Melons
August 31, 2015
This month’s variety specs feature focuses on the latest cantaloupe and melon varieties. Some of the features highlighted include disease Read More
drought management; irrigation; water management
CitrusClear Up Misconceptions About Water Use In Ag
August 31, 2015
Those in the industry need to to clear up misconceptions about water use in agriculture. Read More
FruitsNew Airless Tire For Center Pivots
August 31, 2015
Aperture design provides flexibility over ridges to help prevent overloading of the drive train. Read More
Stone FruitHow Canopy Structures Can Affect Sweet Cherry Productivity
August 31, 2015
We have previously explored orchard cover technologies to modify climatic risks in sweet cherry production, such as rain-cracking and spring Read More
The Latest
Apples & PearsPennsylvania Congressman Supports CIDER Act
August 31, 2015
Freshman Congressman Ryan Costello (PA-06) spent a recent afternoon at Frecon Farms in Boyertown, PA, to tout the CIDER Act, Read More
Oriental Fruit fly
CitrusExotic Fruit Flies Invade South Florida
August 31, 2015
Efforts are under way to eradicate pest that attacks more than 230 different fruits, vegetables, and nuts. Read More
Business PlanningBe Food Safety Recall-Ready [Opinion]
August 31, 2015
No one ever wants to make someone sick after consuming fresh produce, but in spite of the protocols in place, recallls happen and you must be prepared. Read More
Crop ProtectionSustainable Options For Controlling Stink Bug In Vegeta…
August 31, 2015
A researcher from Rutgers University offers pointers to help you control this pest of fruits and vegetables. Read More
CitrusNominations Open For Next Class Of Florida Citrus Hall …
August 31, 2015
Inductees to be honored during the 54th annual Citrus Celebration Luncheon. Read More
CitrusWhole-Farm Revenue Protection Insurance To Be Available…
August 31, 2015
USDA offers greater flexibility for beginning, organic and fruit and vegetable growers. Read More
Cucurbits8 Must-Have Melons
August 31, 2015
This month’s variety specs feature focuses on the latest cantaloupe and melon varieties. Some of the features highlighted include disease Read More
drought management; irrigation; water management
CitrusClear Up Misconceptions About Water Use In Ag
August 31, 2015
Those in the industry need to to clear up misconceptions about water use in agriculture. Read More
FruitsNew Airless Tire For Center Pivots
August 31, 2015
Aperture design provides flexibility over ridges to help prevent overloading of the drive train. Read More
Stone FruitHow Canopy Structures Can Affect Sweet Cherry Productiv…
August 31, 2015
We have previously explored orchard cover technologies to modify climatic risks in sweet cherry production, such as rain-cracking and spring Read More
Fruits6 Tips To Avoid Postharvest Losses
August 31, 2015
Avoiding postharvest losses essentially comes down to knowing what techniques to employ, and what to evade throughout each link in Read More
Insect & Disease UpdateProducts To Help Your Trees Fight Off Citrus Greening
August 31, 2015
Tree decline is one of the major components of citrus greening disease or huanglongbing (HLB). Vectored by the Asian citrus Read More
CitrusGMOs Might Be The Solution To Invasive Diseases [Opinio…
August 30, 2015
Huanglongbing is ravaging Florida’s iconic oranges and California's are at risk; we should not just stand by and watch the U.S. citrus industry dry up. Read More
BerriesRemoving Leftover Roots May Improve New Raspberry Crop’…
August 30, 2015
Soilborne pests and pathogens can be reduced by taking out last year’s red raspberry roots and crowns. Read More
CitrusMany HLB Finds In California
August 30, 2015
Scientists always said it was just a matter of time, but having an incurable disease like Huanglongbing infect the state’s citrus is jarring. Read More
NutsGrowers Claim Pistachio Trees Diseased – Nursery …
August 30, 2015
Whatever the cause, pistachio trees are suffering from Pistachio Bushy Top Syndrome, and tens of thousands of acres in California and Arizona will have to be replanted. Read More
CitrusFederal Judge Blocks Clean Water Rule
August 28, 2015
  According to RISE (Responsible Industry For A Sound Environment), a federal judge in North Dakota has blocked implementation of Read More
PotatoesUSDA Deregulates Late Blight-Resistant Genetically Engi…
August 28, 2015
Agency cites no significant impact of special spud developed by J.R. Simplot. Read More