ANAHEIM, Calif. — Research funded by the Center for Produce Safety housed at the University of California-Davis, was the topic of discussion at a Fresh Summit 2009 session titled “Food Safety Innovations: What’s New and What Does it Really Mean?”
Three of the center’s research grants recipients talked about their work and shared some results, which they emphasized were only preliminary findings that require more study before they can be classified as definitive.
Linda Harris, associate director of the Western Institute for Food Safety and Security at the university, discussed research she has done with E coli and romaine lettuce.
Test lettuce was inoculated with E. coli bacteria to mimic highly contaminated water. Researcher found that the rate of contamination declined rapidly after inoculation and that most of the contamination was on the outer leaves, which often are removed before the product gets to market.
In large studies designed to mimic commercial growing, Steve Koike, plant pathologist and farm adviser for the Monterey (Calif.) County Extension office, said he found that when E. coli was introduced early in the growing process, it had a short persistence rate in the soil and actually became undetectable after 15 days.
Astri Wayadanda, assistant professor at Oklahoma State University, Stillwater, Okla., studied the potential for flies like the leafminer, housefly and blowfly to spread E. coli.
In a 2009 test, none of the flies in a Salinas, Calif., test area were found to be carrying E. coli, though she did not rule out the possibility of flies’ ability to spread the bacteria.
“We think flies may play a role, but it’s probably small,” she said.
Flies may have an effect when “a perfect storm” exists, determined by factors like temperature, humidity and availability of food that attracts flies, she said.
There’s no simple answer to the food safety issue, said panelist Jim Gorny, senior adviser for produce safety for the Food and Drug Administration’s Center for Food Safety and Applied Nutrition.
“No one piece of research is going to give us the answer,” he said. “It’s a mosaic.”