This story is another in a weekly series called "Planting the Seed: Science for the New Millennium." These stories feature ideas and advances in agricultural and environmental sciences with implications for the future.
Washing foods with electrolyzed water can sometimes be up to 10 times more effective at killing harmful bacteria than traditional rinsing techniques, according to one University of Georgia scientist.
"Currently, the food industry washes foods with a chlorine solution to kill bacteria," said Yen Con Hung, a food scientist at UGA's Center for Food Safety and Quality Enhancement in Griffin, Ga. "This method is effective, but it takes time to mix the chlorine solution and to ensure the correct concentration of residual chlorine in the solution."
Hung has been testing a new method, which uses a combination of water, electricity and a salt solution to enhance the properties of water. The water and salt solution flow through a machine called an electrolyzed oxidizing water unit. The positive ions run through one side, and the negative ions through the other. The result is two forms of water; one very acidic and one with very high pH levels.
Kills Bacteria Better
Testing the two waters in his laboratory, Hung found the acidic water very effective at killing harmful bacteria. "We have tested this water on shell eggs, apples, lettuce and cutting boards," Hung said. "It has a very strong bacterial killing effect, and for some applications has better effect than the currently used water/chlorine solutions."
Working with UGA sensory specialists, Hung put the acidic water through consumer tests. "We had trained panelists compare products which were not treated to products treated with the water," he said. "They found no differences in color, appearance or smell."
Hung also tested the high pH water and found it to be extremely useful as a sanitizer. "It works like a soap, and it eases the attachment of proteins and lipids in food materials to the food preparation and processing surfaces," Hung said.
Hung's research findings were published just a few months ago and he is already getting response from the food industry. "The device is manufactured in Japan and Russia, and it isn't being used in the United States, yet," he said. "We have already heard from companies that are interested in using the process here in the U.S."
Perfect for Food Service Operations
Hung envisions the process being used by food service operations first. "The small unit could easily be used in food service facilities," Hung said. "It's easier for workers to use so there would be no excuses for not using it. There's nothing to prepare and mix, and you wouldn't have to leave customers waiting."
He says the unit could also be useful in food processing plants. "In mass production, this technology would be very cost effective," Hung said. "When you want to use it, you push a button. You don't have to worry with mixing up concentrated liquids, and it's more effective than chlorine rinses."
May Be Useful to Processors
In the future, Hung plans to test the application of electrolyzed oxidized water during chicken processing. "We want to use the water on chicken carcasses to see if it cuts down on the levels of salmonella and campylobacter," Hung said. "If it does, this treatment could be incorporated into chicken processing plants."
Hung also plans to test the water on food products that are hard to treat to remove bacteria. "You can't use heat to kill bacteria on products like fresh berries and seafood like raw oysters," Hung said. "The food needs to be safe, but no one wants their oysters to be cooked. They wouldn't be raw oysters any longer."
He also plans to further study what makes the water so effective and which properties in the water work best at killing bacteria.
Home Use Down the Road
"In Japan, there are home units similar to this that are used for treating water," Hung said. "It purifies drinking water and lowers the pH levels."
Hung says he hopes to someday see U.S. consumers using home versions of the electrolyzed water units. "It would be handy and could easily clean your food and sanitize your kitchen," he said. "Until then, consumers should continue to wash their food products at home before preparing them for their families."
(Photographs by Sharon Omahen.)
(Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)