How Does This Apple Spray Keep COVID-19 Away?

A device originally used to decontaminate apples is being repurposed to sanitize N95 masks, to help keep healthcare workers safe.


The COVID-19 pandemic has triggered worldwide shortages of N95 masks — specialized personal protective equipment that frontline healthcare workers desperately need to stay safe as they care for infected patients. They were never designed to be used twice.

Normally, N95 masks are treated as single-use disposable items, but these days workers are often forced to wear the same mask for an entire shift in an effort to conserve them. Even with companies ramping up production, supply can’t keep up with the spike in demand.

So the race is on to find technologies that could decontaminate N95s for reuse, and one technology with Health Canada approval came from an unlikely source: a device originally designed as part of the process to make gourmet candy apples.

Paul Moyer and his family have been farming apples in the Niagara region for over 200 years. His generation started making candy apples, but their new venture was threatened by a deadly listeria outbreak in 2015. People were rightly afraid that apples on the market could be contaminated.

Keith Warriner, professor of food science at the University of Guelph, stepped in to help the Moyers find a solution. The result was the Clēan Flow Mini: a unit that looks like a cross between a barbecue and a tanning bed that can decontaminate 10,000 pounds of produce every hour.

The fruit or vegetables are fed into the treatment chamber on a conveyor belt. Here a mix of hydrogen peroxide, ozone, and ultraviolet light kill 99.99 percent of pathogens, both on the surface and subsurface of produce, in 30 seconds. For comparison, operating room sterility is only 99.9 percent.

Moyer’s Apple Products is now a co-owner of the invention, which has garnered international recognition, including the 2019 International Association for Food Protection Food Safety Innovation Award.

When the pandemic hit, Moyer quickly realized that this same technology might be useful in decontaminating N95 masks. And he had a five-year head start on the novel coronavirus.

The Clēan Works team started out by testing pathogens, like E. coli, that are even more hardy than SARS-CoV-2 (the virus that causes COVID-19). N95 masks came out sanitized, just like an apple would. Rebranded as the Healthcare Mini, the Health Canada-approved device can decontaminate up to 800 masks an hour.

Each week, 15 of these compact and mobile units are now being produced for hospitals, long-term care homes, and more.

During this public health emergency, many businesses are pivoting to solve problems in unique ways. This homegrown solution to the N95 mask shortage is already helping protect Canadian healthcare workers.

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Karyn Ho is a science animator and engineer who thrives at the interface between science, engineering, medicine, and art. She earned her MScBMC (biomedical communications) and PhD (chemical engineering and biomedical engineering) at the University of Toronto. Karyn is passionate about using cutting edge discoveries to create dynamic stories as a way of supporting innovation, collaboration, education, and informed decision making. By translating knowledge into narratives, her vision is to captivate people, spark their curiosity, and motivate them to share what they learned.