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Joellen Feirtag

Joellen Feirtag, a University Extension food scientist, is testing the ability of an electrolytic process to disinfect fresh produce.

Taking aim at polluted produce

University researcher probes a promising produce purifier

By Deane Morrison

Dec. 19, 2006

In this era of E. coli and Salmonella outbreaks, consumers are concerned about harmful bacteria and viruses hitching a ride on fresh fruits and vegetables. But few want their produce dipped in harsh disinfectants that will damage the environment or human health. That was the backdrop a week ago, when the media spotlight fell on Joellen Feirtag, a University professor of food science and nutrition. She is testing a way of purifying produce using only a dilute salt solution and an electric current. The technology, called ECT (electro-chemical activation), was developed by Russian scientists to get rid of bacterial films gumming up oil and gas pipelines. Feirtag, a microbiologist, is helping companies that handle fresh produce assess ECT's potential in the food arena. According to estimates by the Centers for Disease Control, foodborne agents cause approximately 76 million illnesses, 325,000 hospitalizations and 5,000 deaths in the United States each year. The causes range from mild viral infections to fatal illnesses and include poisoning by metals as well as living pathogens. In her studies of ECT, Feirtag performs experiments that recreate the situation in agricultural fields, where pathogens may be introduced by contaminated irrigation water sprayed on crops. The process works by running a solution of table salt, which is composed of sodium and chlorine ions, through the ECT module, where an electric current separates the chlorine and the sodium into adjacent chambers. In one chamber, chemical reactions form disinfectant compounds. In the other chamber, detergent compounds form. The disinfectant and the detergent flow out of the module in separate streams.

"To me, this is a new technology that works ... Through education and new technology, we may be able to reduce outbreaks of E. coli," says Feirtag.

"You can use the detergent to remove organic matter, then dip the produce in the other to kill pathogens," Feirtag explains. Early results with such items as lettuce, tomatoes and spinach have been encouraging. When Feirtag sprayed the produce with several strains of E. coli, the ECT treatment achieved kills of eight orders of magnitude; that means that for every bacterial cell that survived the treatment, between 100 million and one billion were killed. The process also killed the intestinal pathogen called norovirus, plus a strain of avian flu and hepatitis A, and it removed Salmonella from plastic surfaces. A 30-second dip in the disinfectant stream was enough to kill the pathogens. Feirtag and her colleagues are collecting a month's worth of data at a produce facility. While not revealing the identity of the facility, Feirtag did say that Dole Food Co. was looking into the process for its fruit and vegetable plants in California. Feirtag has also been visiting other companies with produce processing plants, including ones that make sandwiches and salads, in an effort to introduce ECT technology more widely into U.S. industry. She says the units can handle 75 gallons of the salt solution per day in a small plant and have potential for use in hospitals and cities. The two streams exiting the ECT modules can be remixed and reused; this is done at plants in Europe and Russia, she says. Feirtag is also gathering data on the efficacy of different salt solutions for publication in peer-reviewed journals. Efficient though it may be, the ECT technology could never unilaterally eliminate infectious bacteria and viruses from food. Feirtag herself, along with a friend, once contracted hepatitis A from a restaurant after a cook with the virus had handled the cheese in their cheeseburgers. ECT may, however, find a place in the fight against foodborne illnesses. "To me, this is a new technology that is economic, that works, and that is efficient and safe for the environment and people," Feirtag says. "Through education and new technology, we may be able to reduce outbreaks of E. coli. We don't want people to stop eating fruits and vegetables."