Device may help eliminate bacteria in food

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3/11/2009-A Purdue University researcher has designed a device that may help eliminate bacteria in packaged foods. The device consists of a set of high-voltage coils attached to a small transformer that generates a room-temperature plasma field inside a package, ionizing the gases inside. The process kills harmful bacteria such as E. coli and Salmonella. By placing two high-voltage, low-watt coils on the outside of a sealed food package, a plasma field is formed. In the plasma field, which is a charged cloud of gas, oxygen is ionized and turned into ozone. Treatment times range from 30 s to about five min. The longer the gas in the package remains ionized, the more bacteria that are killed. Eventually, the ionized gas will revert back to its original composition. The process uses only 30–40 W of electricity, and the outside of the container only increases a few degrees in temperature, so its contents are not cooked or otherwise altered. Other methods of ozone treatment require adding devices to bags before sealing them to create ozone or pumping ozone into a bag and then sealing it. This method creates the ozone in the already sealed package, eliminating any opportunity for contaminants to enter while ozone is created.

“Conceptually, we can put any kind of packaged food we want in there,” said Kevin Keener, an Associate Professor in the Dept. of Food Science, Purdue Univ. “So far, it has worked on spinach and tomatoes, but it could work on any type of produce or other food.” According to Keener, testing has worked with glass containers, flexible plastic-like food-storage bags, and rigid plastics, such as strawberry cartons and pill bottles. A patent on the technology is pending. Keener said the next step is to develop a commercial prototype of the device that could work on large quantities of food.

The study was published in LWT - Food Science and Technology.




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