Irrigation Water, Animal Contamination, Seasonality Among Topics at Third Produce Safety Symposium

More than 300 industry representatives, academic researchers, and representatives from regulatory agencies gathered at the University of California-Davis on June 27 for the Center for Produce Safety’s third annual Produce Research Symposium, organized around key topics in good agricultural practices in food safety.

Among the most interesting research findings presented, according to Bob Whitaker, PhD, chief scientific officer of the Produce Marketing Association, included results from CPS-funded studies of risk factors for transferring animal pathogens to fruit and vegetables. “The bottom line is that while animals are an important factor that need to be included in any risk assessment for the production of food, current measures probably work very well to limit that risk,” Dr. Whitaker said. “It’s pretty reassuring.”

After articles in the popular press linked the 2006 E. coli outbreak associated with spinach in California’s Salinas Valley to contaminated irrigation water, local growers began testing their water for E. coli levels. In a session on irrigation water quality, UC-Davis researchers presented findings growers had expected: “More than 99% of the time, you just don’t find any evidence of contamination in irrigation water whatsoever,” Dr. Whitaker said.

Research on seasonal trends in produce contamination indicated that pathogens tend to cause more trouble in the hotter summer months. “We may want to research that further and find out what causes that phenomenon,” Dr. Whitaker said. “It also points out that just assaying everything all year round may not be the best use of our resources.”

Dr. Whitaker was particularly excited by research from the University of Delaware on the use of zero-valent iron to mitigate contamination in irrigation water. “This is basically scrap iron that you grind up and combine with a sand filter, which a lot of growers already use to remove particulates from water,” he said. “It has an electrical charge that binds up pathogens. It’s an approach that’s pretty cheap and just adds one more piece to something that most growers are already doing, so small operators could enact this precaution without much cost to them.”