Ohio State developing cutting-edge technology to fight food bacteria

COLUMBUS -- Food scientists at The Ohio State University lead the nation in research that may soon change the way foods are processed and preserved. The developing technology, Pulsed Electric Field (PEF), substitutes the use of heat with bursts of electricity to keep fresh foods safe and flavorful.

“This is subtle technology,” said Ken Lee, professor and chair of Food Science and Technology. “There’s enough energy being put into the food to kill the bacteria, but not so much energy as to cause it to heat up or to cause chemical breakages or flavor changes.”

The research, which uses a key treatment process called electroporation, began in 1994 under Howard Zhang, associate professor of food process engineering.

In a fruit like apples, juice is squeezed and pumped through the PEF testing chambers for treatment. At that point, an electrical field builds over bacterial cell membranes, like a water balloon, to break them down. The process causes the microorganisms to lose their life-supporting substances and die. The treated juice is then packaged into containers for consumption.
Zhang said the benefits of the technology are tremendous.

With Ohio ranking 10th nationally, with about 102 million pounds harvested a year, PEF could change the industry significantly, he said. The technology would allow apple juice and cider to be processed, sterilized and even packed at an orchard.

In addition to freshly squeezed fruit and vegetable juices, specially formulated products such as protein-fortified orange juice, immunologically enhanced soy milk, yogurt drinks, salsa and salad dressings also have been tested. Results indicate that the technology maintains quality, extends shelf life and improves the safety of such products.

Research is conducted in a 3,700 square-foot pilot plant where two key U.S. patents relating to the processing equipment and technology have been granted. The PEF chambers were designed and built by Zhang and equipped with a pulse generator and an aseptic processing system.

The plant is capable of processing at a high speed of nearly 2,000 liters of liquid per hour. The aseptic processing component tests variations of food packaging that prevent bacteria and other contaminants from entering the packages.

Current research funding is provided through multiple federal, state and private grants totaling $3 million. Zhang said the next step is to transfer the technology to the private industry. Research will continue in developing functional foods that could one day remedy illnesses related to bacteria and weakened immune systems.

The technology will soon be shared internationally with testing units, manufactured at Ohio State, scheduled for shipment to researchers in Spain and Australia.

“This is a university and the purpose of a university, fundamentally, is to improve the human condition through research and to improve the quality of life,” Lee said.

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