Making Fresh Food Safe Food

Research, Producer Education and Tighter Government Controls Boost Food Safety

By Beth Forbes

It's ironic, but foods considered among the most healthful and nutritious—fresh fruits and vegetables—can also be carriers of deadly bacteria.

In recent years, foods such as cantaloupe, strawberries, peppers and spinach have been implicated in large food-illness outbreaks and national food recalls. Fresh foods present food safety challenges unlike those for more processed foods, in which contaminants are destroyed in the production process. And with greater distribution of fresh foods, a problem on just one farm can sicken thousands in several states.

A Charge to Kill Pathogens

Kevin Keener is developing methods using cold plasma to kill bacteria in packaged fresh foods.
Kevin Keener is developing methods using cold plasma to kill bacteria in packaged fresh foods.(Photo by Tom Campbell)

In an effort to improve food safety for fresh foods, Kevin Keener, Purdue University professor of food science, tested a technology with food products that turns air into a killing agent for pathogens. He uses electricity to generate cold plasma that ionizes the air molecules within a packaged food product. In as few as 20 seconds, the charged air molecules eliminate bacteria such as E. coli from food surfaces.

After a few hours, the air within the package returns to normal, and the food product is bacteria-free. "The cost is comparable to that for chemical and heat treatments currently used and may be more acceptable to consumers than techniques such as chlorine washes and irradiation," Keener says.

The key for companies adopting greater food safety measures such as his technology may be the added benefits of extending the shelf life of fresh food products. Spoilage is a major cost for food companies.

Keener is working with colleagues in Europe to perfect the process.

Kevin Keener explains how cold plasma creates bacteria-killing molecules to make fresh food safer.

Food Safety Starts on the Farm

Concurrently, Keener and a team of Purdue experts are working with producers to improve food safety practices on the farm. Government agencies have stepped up surveillance measures, thanks to increased interest in food safety from Congress.

Keener says federal inspections of produce farms are stricter now than in the past. The Food and Drug Administration may recall produce even when no foodborne illness has been reported. A recall could be triggered for produce produced under unsanitary conditions, or without complete process records, or if it contains a pathogen.

"The FDA has always had the power, but now it also has the political will," Keener says.

Concern over food safety has also increased at the state level.

"Providing fresh fruits and vegetables that are healthful has always been the goal and responsibility of the farmer who produces them. Recent regulatory changes by the Indiana State Department of Health also require an additional level of accountability for farmers who want to sell to customers other than the end consumer," says Jodee Ellett Purdue Extension's local foods coordinator.

She says farmers who sell to Indiana restaurants, brokers, wholesalers, food hubs and some auctions must register with the state as fruit and vegetable wholesalers and indicate they follow good on-farm food safety practices.

At several Purdue Extension workshops last year, producers learned food safety information on health and hygiene, water quality, animals and animal products, sanitation, recordkeeping and farm food-safety plans.

Scott Monroe, Purdue Extension educator in Daviess County who is part of the education effort, says, "We want to help ensure Indiana farmers are producing the safest and most wholesome products possible."