21-05-2025
University of Guelph prof's waterless decontamination technology is changing food safety
A University of Guelph professor's technology is changing the way we take care of our food.
Keith Warriner, a professor of food safety, has developed a technology that combines hydrogen peroxide, UV light and ozone to create hydroxyl radicals, which kill 99 per cent of pathogens such as E. coli and salmonella.
He first developed the technology over 20 years ago in the United Kingdom, using the same chemistry that forms hydroxyl radicals.
He said hydroxyl radicals are seen in clouds. When the sun shines into the ozone, it degrades into hydroxyl radicals and dissipates into water. Warriner put that chemistry to work in a chamber to decontaminate fresh produce, such as lettuce, tomatoes and cauliflower.
The technology's water-free system has advantages over conventional methods.
'To be effective, it can decontaminate. You don't have any water, so you're saving on water, it can degrade pesticides like chlorpyrifos, whereas in washing, it's like having a bath, literally,' Warriner said.
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The system can decontaminate 100,000 pounds of produce every hour and works on fruits, vegetables and raw pet food.
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However, the prototype never caught on until years later, when a listeria outbreak occurred in 2015 and the technology was used to help save Ontario apple grower Paul Moyer's business.
Moyer turned to the award-winning food scientist for help.
'He would say, 'Look, we need a process where we can assure that apples are going to be listeria-free, and I said, 'I've got this technology from previous research.' And we did the project. Sure enough, we showed that we could inactivate the listeria, make the candy apples safe,' Warriner said.
The technology resulted in massive success; it boosted Moyer's sales tenfold, doubled the fruit's shelf life and allowing it to be sold in multiple states south of the border.
The success also led to Moyer starting Clean Works Technology in 2017, partly owning the patent for Warriner's technology.
The U of G professor and his team of food science students are currently looking at ways to improve the technology, including developing versions that might work on eggs and medical equipment, among other commodities.
Warriner said it's going to be 'a game-changer' for food safety. He said it has all the features needed for industrial applications.
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'You've got the throughput, you've got monitoring, you've got research that's proven research and it works,' he said.
He said trying to get others to buy in presents a barrier, as is the case with all new technologies.
And it's a barrier he is trying to overcome.
'The reality with fresh produce is that it's grown in an open field, and we know urban populations where also water quality is affecting it, so testing alone won't save you, but having a pasteurization step, as I call it, will save your day,' he said.
More than 200 studies have been done to validate the technology's safety and efficacy, and it's led to commercial units expanding to other continents, including Europe, South America and Australia.
