PurdueAgricultures

Growing Pains

Rapid growth in fresh-cut produce bring food safety issues to forefront

By Olivia Maddox

When Dianne Wyman was raising her young family in Southern California in the 1970s, she and her children often drove into the San Fernando Valley to buy produce straight from the fields. “If we got a stomachache following our trip, we never made the connection that it might have been from the produce,” she says.

Now a resident of Franklin, Ind., Wyman still makes forays into the countryside for fresh produce, but the retired educator is more careful about where she gets it. “If there’s a produce farm surrounded by cattle farms on all sides, I’m not likely to stop there.” She uses equal care when buying from her neighborhood supermarket. “I shop at a large store that moves a lot of produce through quickly, so what I get is more apt to be fresh,” says Wyman, who inspects for color, signs of aging and odor. “I also try to buy brand names, because they are more likely to have quality-control programs in place.”

Wake-up call

The need for vigilance with produce was underscored in fall 2006 when fresh, bagged spinach sickened 205 people, resulted in three deaths and culminated in a nationwide recall of the product. Within days, the spinach was traced to California’s Salinas Valley, an area known as “the salad bowl of the world” because of all the produce grown there. The resulting investigation found the leafy vegetable was contaminated with E. coli O157:H7, most likely from irrigation water contaminated with cattle feces.

While this type of E. coli was linked to beef in the early 1980s, it’s only been in the last decade that scientists have associated it more frequently with fruit and vegetables, according to Richard Linton, director of the Purdue University Center for Food Safety Engineering and associate director of agricultural research programs. For most of the ’90s, the produce industry was out of the limelight. Instead, regulatory efforts focused on meat, poultry and seafood, culminating in mandatory Hazard Analysis Critical Control Point (HACCP) programs that minimized risk.

In the aftermath of the 2006 spinach contamination and smaller regional outbreaks, HACCP or other food safety initiatives are now recommended for fruits and vegetables. “There’s been a big change in the last decade as to what kinds of contaminated food products cause illnesses,” says Linton, whose research focuses on solving food safety problems through applied research. “More people are eating fruits and vegetables for the health benefits. If you look at a graph line of increased consumption of fruits and vegetables and the line of increased food borne illnesses associated with them, they’re almost parallel.”

Linton is among the nation’s leading food scientists who are helping the produce industry and federal regulatory agencies grapple with reducing contamination in fresh-cut, ready-to-eat fruits and vegetables, one of the fastest-growing segments in the food market. Accomplishing this, he says, will require a combination of science and education, from developing breakthrough technologies that are up to 1,000 times more effective in reducing microbial levels to establishing standardized agricultural practices for both domestic and imported food (go to

Raising the standards

While consumers like Wyman should continue to exercise diligence about food safety (see Linton says the industry as a whole must do more to improve safety practices from farm to table. “We need to be better in order to lessen the amount of contamination from farms and during distribution for foods that are ultimately delivered to retailers or consumers. Right now, manufacturers don’t have effective washing procedures that can reduce E. coli, salmonella and other organisms to a safe level,” he says. “If you have E. coli O157:H7 on your lettuce—or other fruits and vegetables—at an unsafe level, you can’t wash it at home to make it safe. The only thing you can do is cook it.”

Linton explains that the Food and Drug Administration (FDA) recommends a 100,000-fold reduction in pathogens on fresh-cut produce, but traditional sanitizing washes only provide about a 100-fold reduction. “We’re 1,000 times away from where we need to be. Raising this percentage is the FDA’s No. 1 initiative,” says Linton, who, in addition to his research, has developed internationally recognized food safety, HACCP and sanitation training programs for producers and manufacturers. “There’s a tremendous amount of effort being put into developing technology and getting it right to industry.”

Technology on the fast track

Purdue’s is among some 50 leading university research programs at work on new or improved technologies that range from irradiation to better washing agents. “This emphasis on technology transfer is one of the fastest areas of risk reduction that we’ve seen in a long time,” Linton says. The veteran food scientist collaborates with a multidisciplinary research team that has developed a new treatment method using a non-toxic chlorine dioxide gas to kill pathogens.

Food science colleagues Mark Morgan and Philip Nelson are key members of the research team who contribute processing and engineering strategies in a usable form for industry. The new process underwent initial testing earlier this year in the Department of Food Science’s pilot lab, which simulates an industry setting. The treatment is currently being evaluated at a University of California Davis-affiliated industry center and may be available for widespread use later this year.

Linton says the search for more effective treatments is not limited to discovering new technologies but developing those that satisfy the factors of cost, time and acceptance by manufacturers and consumers. “There are a lot of great technologies out there, but they don’t fit within the food system. It may be that they’re not affordable for industry use, that they lessen product shelf life, or that they negatively change appearance or taste,” he says. “If the product is safe, but no one will eat it, that’s not what we want. We have to ask, ‘Will this work for industry?’”

Common goals for global production

While technology will have the most impact for manufacturers, education will make the most difference on the farm. Linton, whose research has taken him to the Salinas Valley field where contaminated spinach was grown, says on-farm priorities include improving practices related to manure management, irrigation water and worker hygiene.

The strategies for safer production for farmers in one of our nation’s most fertile valleys can be applied to producers in other countries as well. “In the ’70s or ’80s, if you purchased tomatoes, they were likely grown locally. You didn’t get them from California or other parts of the world. Now, we have blueberries from Chile, raspberries from Guatemala—we have a wide variety of produce options from around the world,” Linton says.

Good Agricultural Practices, commonly referred to as GAPs, can help improve the quality and safety of produce no matter where it’s grown. GAPs provide recommendations for four components of production and processing—soil, water, hands and surfaces—and include ways to identify and reduce individual on-site risks. In the Salinas Valley, for example, this could involve changing the way spinach is grown so that it is less likely to be contaminated by irrigation water, says Linton, who is a collaborator for the National Good Agricultural Practices Program. Purdue Extension includes GAPs among the topics presented at workshops and seminars for commercial growers in Indiana.

Educational byproducts

Even though new technologies are on the horizon, Linton emphasizes that there is still a substantial need for produce research. “Increased awareness has promoted significant increases in food safety research and funding opportunities. The industry is on board and putting resources into solving food safety problems,” he says. Congress is also considering legislation that would more closely regulate imports, increase funding for food-safety agencies, and provide competitive grants for research and educational outreach.

In the 30 years since her expeditions into California’s produce fields, Wyman says she’s become an informed consumer because of food safety research and educational programs offered by Purdue Extension. “A lot of things can panic consumers,” she says about the food-safety debate. “Years ago, after safety concerns first surfaced about poultry, I never wanted to eat chicken again. But if handled correctly, you have a really excellent chance of not getting contaminated food. As a consumer,” she asserts, “I think we’re moving in the right direction.”

Purdue Agricultures / Story Link
/

1