Skip to main content

Fresh veggies need a good scrubbing to prevent contamination, WVU researcher says

Red, green, and orange tomatoes are shown on a table with a red and white tablecloth at a local Farmers Market. There are other vegetables in the distance.

Research from the West Virginia University Davis College of Agriculture, Natural Resources and Design and WVU Extension suggests that even produce from local farmers markets could use a good scrubbing to rid fruits and vegetables of pathogens. (WVU Photo)

Download full-size

Consumers need to be cautious of bacteria lingering on foods no matter where they’re purchased — even at local farmers markets, according to West Virginia University research.

Cangliang Shen has studied the microbial safety of both local farmers market produce and mobile poultry processing units, which revealed a risk in areas for microbial infection from bacteria like E. coli, listeria and salmonella.

Shen’s work falls under the umbrella of both Davis College of Agriculture, Natural Resources and Design and WVU Extension.

“These projects are research- and extension-integrated for microbial safety in our West Virginia local community,” said Shen, associate professor of human nutrition and foods.

“These are the two programs we recently got funded by the U.S. Department of Agriculture’s National Institute of Food and Agriculture, through the CARE Program, which is a critical research and extension integrated program.”

In a preliminary 2015 study that Shen and graduate students KaWang Li and Wentao Jiang conducted with the WVU Small Farm Center, a microbiome analysis of fresh produce in a northern West Virginia farmers market revealed pathogenic salmonella and listeria were both present.

“We are developing some interventions strategies to control those pathogens, which also can be found on grocery store produce,” said Shen, whose research thus far focuses only on farmers markets and mobile poultry processing units. “It’s common to find both pathogens on chicken at the supermarket, as well.”

The results of the study indicated that triple washing vegetables is the most effective way to limit risk. This involves two separate water washes — which eliminate dust, soil and organic matter — followed by a dip in an antimicrobial sanitizer and disinfectant called SaniDate-5.0.

“Definitely the soil and the dust have to be removed,” he said. “That's why the two steps of the water wash are important. Most of the contamination is coming from the soil. We found generic E. coli, the microorganism that indicates fecal contamination. That’s higher in fresh produce, so you have to rinse and remove the soil.”

When bringing vegetables home, Shen said it’s best to wash and dry them, separate them from other vegetables and put them in a zip-top bag in the refrigerator. They should be consumed within 72 hours, while unrefrigerated, perishable vegetables should be eaten that day.

“Definitely do not leave the perishable fresh produce out overnight,” he said.

Based on his preliminary results, Shen and his team received USDA-NIFA funding for more research and extending it to the local community.

“We had a stakeholder — the Preston County Workshop,” he said. “They have squash processing plants. We went there in 2019 to do an on-site shelf-life study.”

The results revealed that SaniDate-5.0 could extend the shelf life of squash with minimal extra cost.

“We also found that using higher concentrations does not necessarily mean you will improve the antimicrobial efficacy,” he said. “That’s very important. Some small farms think the more you add, the more effective it will be, but it’s not necessary.”

The researchers hope to conduct outreach via Extension.

“We would love to publish a readable menu with some layman language,” Shen said. “It will explain what ‘fresh produce’ means. What is triple washing? What is SaniDate? Then we will be publishing data on all the different produce commodities. We’ll cover cucumber, spinach, tomatoes, squash and a little bit of agriculture and economic analysis.”

For growers who live in mountainous areas without internet access, they’ll offer a CD with this information.

“I also have my own videos which are for teaching and research and Extension,” he said. “And we’ll be using the Preston County Workshop’s processing plant to do outreach training.”

In addition to produce, the funding will allow Shen to look at poultry processing safety in two mobile processing units owned by the West Virginia Farmers Market Association and Department of Agriculture. Local producers can rent these facilities to process their birds, and Shen and Joe Moritz, professor of poultry science, will be studying the microbial safety of the units.

All the studies are still preliminary, and Shen and his students — Rebecca Stearns, Corey Coe, Peighton Foster, Jesica Temple, Connor Freed, Carly Long — hope to reach many farmers across the state.

“We still have lots of work to do,” he said. “West Virginia is a mountainous area, and agriculture is not a major industry here compared to other states, but I do think our small farmers are important. We have a lot of opportunity to do research and outreach for them.” 



MEDIA CONTACT: Laura Roberts
Research Writer
WVU Research Communications

Call 1-855-WVU-NEWS for the latest West Virginia University news and information from WVUToday.

Follow @WVUToday on Twitter.