Researcher zaps bacteria with ozone
By Courtney Dickerson
Photo provided by Tom Campbell, Purdue Agricultural Communication
Kevin Keener demonstrates in-bag ozonation, which kills bacteria without heating food. This revolutionary technique could be used for everything from food safety to national security.
A Purdue researcher has spent the last few years developing a machine that could take food, bowling shoes, toys and countless other household items to a new level of clean.
Kevin Keener, associate professor of food science, created a small device that looks like an ordinary bug zapper, but it works like an extraordinary plasma blaster straight from a science fiction movie.
Keener calls his device an in-package ozone machine, because it uses ozone and ionization to destroy bacteria. It can kill bacteria without harming the food with heat or chemicals. "Conceptually, we can put any kind of packaged food we want in there," Keener said. "The process can make your fresh and processed vegetables much safer to eat."
Keener's device zaps out harmful bacteria in food such as Salmonella and E. coli, which can be deadly culprits in food poisoning. There is always a risk of bacteria hiding in food, Keener said, but the zapping machine can virtually eliminate the harmful, microscopic bacteria before it hits the dinner table.
Keener's ozone machine is not the original or only food safety zapper, but it is the first one that does not affect food quality. Earlier devices actually heated food to destroy the bacteria, and they did not work with all types of packaging. Keener's machine and process works with all types of containers from metals to plastics to wooden crates.
Keener said it would both a source of pride and relief to be able to go into a grocery store and know that the food consumers are purchasing is safe from harmful bacteria.
Implications for the device go far beyond the food industry. Keener developed it for food safety, but he said it has potential for countless other cleaning and sanitation uses. It uses a battery charger to change the oxygen inside the food package into ozone, which then helps kill the bacteria.
"It's kind of like charging a battery without electrode intrusion and no food or package gets damaged during the process," he said.
Keener's work started at North Carolina State University, where he researched ways to decontaminate military items. Originally, the zapping machine was similar to a microwave oven chamber. The chamber ionized items that might be contaminated with strands of harmful bacteria or viruses. "I knew this process could be used in food safety," Keener said.
And that's what he set out to do when he arrived at Purdue in 2005. But research funding was limited, so he looked for common, inexpensive items he could use to build the machine. "The construction is very simple," said Keener. "Anybody could maek this in a garage or dorm room for a couple of hundred dollars."
That's because the machine is not much more than two high-voltage coils hooked to an electric transformer.
Keener does not work alone and the research did not happen overnight. It took his team more than two years to tweak the process and perfect the device. Both the process and device have been submitted for a patent.
Now his team is looking forward to working on a larger scale by developing prototypes for commercial and industrial settings - in food processing and beyond.
"The shoes we wear at the bowling alley could be bacteria- and odor-free with the concept of this device," Keener said. "It would be a relief for parents and daycare employees alike to able to sterilize the toys that children handle repeatedly."