Research to find an effective postharvest washing solution for organic produce is being spurred by a $2 million grant from the from the U.S. Department of Agriculture.

Researchers at the University of Tennessee Institute of Agriculture and North Carolina State University are involved with a multi-year study that began last fall with a grant from the USDA’s Organic Agriculture Research and Extension Initiative, according to a news release from the universities.

“The goal of the project is to provide safe, alternative, sustainable and effective treatments to reduce foodborne illnesses caused by E. coli, listeria and salmonella contamination in organic produce,” Qixin Zhong, an associate professor in the UT Department of Food Science and Technology, said in the release.

While allowed for organic produce, chlorine in wash water is not preferred, said Penelope Perkins-Veazie, a professor and postharvest physiologist with NCSU’s Plants for Human Health Institute.

“The problem that organic people have had with it is that it is not exactly considered sustainable,” she said.

The chlorine smell and difficulties in monitoring chlorine levels add to the need for alternatives, Perkins-Veazie said.

Zhong said in the release that the group hopes to provide effective treatments in the form of alternative organic antimicrobials — naturally occurring substances such as organic essential oils that fight pathogens like E. coli — added to postharvest wash water.

“To improve microbiological safety of organic produce, there is an urgent need to develop washing practices that not only enhance sanitation effectiveness but also fulfill the requirement of organic fresh produce,” Zhong said in the release.

Effective treatments are being sought in the form of naturally occurring substances such as organic essential oils, which can kill pathogens like E. coli when added to postharvest wash water, according to the release.

The projected four-year study, “Alternative Post-harvest Washing Solutions to Enhance the Microbial Safety and Quality of Organic Fresh Produce,” will consider the economics of alternatives, potential changes in taste and smell, and the effect on shelf life, according to the news release.

“We have started the preliminary testing and just now getting to the stage where we are getting our base anti-microbial systems together,” said Faith Critzer, a University of Tennessee extension specialist and faculty member of the UT Department of Food Science and Technology.

If successful, research could also lead to changes in processing conventional produce, she said.

The food industry is looking for label-friendly alternatives to traditional antimicrobials, she said.

“If you can say something is a cinnamon extract versus sodium benzoate, (consumers) know what cinnamon is,” Critzer said. “End game, we’re trying to find a couple of good solutions that fit the bill for organic growers.”

Researchers plan to consult with a group of organic produce growers at least every six months about the progress of their work, Critzer said.

Researchers will also share findings through Web seminars and other media, according to the release.

Other researchers on the project are:

  • P. Michael Davidson, UT professor of food microbiology;
  • David Lockwood, UTennessee professor and extension specialist in fruit and nut crops;
  • Annette Wszelaki, UT assistant professor and commercial vegetable extension specialist;
  • Jonathan Baros, NCSU farm and agribusiness management;
  • Jeanine Davis, NCSU associate professor and extension specialist in organic crops;
  • MaryAnne Drake, NCSUniversity professor in sensory analysis and flavor chemistry; and
  • Diane Ducharme, GAPs program coordinator and extension associate in horticulture and food safety at NCSU.