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Exposure to an electrical field can kill harmful bacteria in foods, says scientist at Purdue University


West Lafayette, Ind. – Research out of Purdue University has found that exposing packaged liquids and fresh produce to an electrical field for just minutes might eliminate all traces of foodborne pathogens.

The scientist behind the discovery is Kevin Keener, a professor of food science at the university who was looking for new ways to kill harmful bacteria, such as E. coli and Salmonella.

Keener’s method uses electricity to generate a plasma, or ionized gas, from atmospheric gases inside the food package, says the university.

This process creates a wide variety of bacteria-killing molecules including ozone, nitrogen oxides, hydrogen peroxide, and others.

These molecules only exist for a few hours, says the university, and then revert back to the original atmospheric gas, leaving a bacteria-free product.

New method effective

The university adds that Keener and researchers at the Dublin Institute of Technology demonstrated that sealed-package atmospheric plasma works well to kill bacteria in growth media.

Their experiments showed that bacteria on these surfaces were eliminated with 20 seconds of treatment and 24 hours of exposure to the gases it creates.

Keener adds the cost of the process should be comparable to current chemical and heat treatments used to sanitize foods.

“Even in the most resistant bacteria-growing media, 45 seconds of treatment gave us complete elimination of the E. coli,” says Keener.

“Under a microscope, we saw holes forming in the cell walls of the bacteria.”

Adapting the technology for liquids could allow development of portable devices to clean drinking water in areas with contamination or that lack other purification methods.

It could also allow food processors to bottle juices without first heating them, a process widely used to kill bacteria that can alter products.