Not long after COVID-19 erupted in New York City, Bobbie Lloyd, the chief operating officer of Magnolia Bakery, spent thousands of dollars to do a deep clean of their 5,000-square-foot production facility in Harlem. Ultimately, she decided she had wasted her money. “One sneeze, one touch. That’s all it takes,” she says, to reintroduce the virus.

Lloyd and her immunocompromised husband began researching other options to add an extra layer of sanitization to the bakeries, in addition to taking employee temperatures upon arrival, requiring face masks and gloves, and cleaning throughout the day. They decided on newly-developed technology by Florida-based company Healthe, which emits continuous, low doses of ultraviolet radiation, called far-UVC, or wavelengths around 220 nanometers.

Soon, their West Village and Upper West Side locations will have UV-emitting ceiling lights and air conditioning units as well as a step-through “Cleanse Portal” that customers walk through to sanitize themselves in far-UVC light upon entry. High doses of UVA or UVB (280-400 nm) can harm human skin or eyes, but far-UVC is a sweet spot—able to kill viruses and bacteria without the threat of causing blindness or skin cancer in humans.

At a fraction of the cost of the deep clean, Lloyd says the far-UVC installations will give customers and staff an extra layer of confidence. “This won’t take the place of proper cleanliness, wearing a mask or gloves,” says Lloyd. “It’s just another level of safety. The way I look at it, if there’s no harm, it can only do good.”

Lloyd isn’t alone in investing in UV technology. A number of food businesses around the country are incorporating it in their sanitization practices. From the Bay Area’s BambooAsia to Cameo Pizza in Sandusky, Ohio, eateries are advertising the use of UVC light treatments to keep patrons and staff safe. And James Marsden, former White House advisor who sits on Chipotle’s Food Safety Advisory Council, recommended its use.

Although President Trump was lambasted for suggesting UV light could be used internally to treat COVID-19 patients, the technology is appealing to restaurants in 43 states that have moved to re-open dine-in service around the country and keep dining rooms safe. But kitchens—which are often small, cramped, and poorly ventilated—pose an equally important set of challenges for restaurant staff.

UV lamps have been used to disinfect hospitals and the New York City subway and have proven helpful, so it is reasonable to assume they would also help in a restaurant environment, says David Welch, a researcher at the Center for Radiological Research at Columbia University in New York City. Their efficacy, however, hasn’t yet been thoroughly tested on COVID-19. And Welch and other experts say that while some of the many UV devices swiftly making their way onto the market have potential benefits, they may pose more harm than good if they’re not used correctly.

“We’re still learning more about how COVID-19 is spread, whether it be through surfaces or airborne routes, so it’s really tough to predict the specific effectiveness, but UV is an important tool that can be part of the overall protection plan,” says Welch.

An Extra Level of Cleanliness?

Before reopening Ciena Agaves, a chain of Arizona-based Mexican restaurants, manager Bob Shulken sent a 5-foot-tall robot on wheels in to the restaurant alone to emit UV light in 20-minute bursts in different parts of the building. In addition, an antimicrobial coating called Omni Shield, which is supposed to last between 60 and 90 days, was sprayed onto surfaces.

Like Lloyd, Shulken was looking for an extra level of cleanliness. “It’s about making sure your facility for serving people is completely safe,” he says.

While these aren’t bad practices, there are a few things to consider. “The problem with UV light is that it only travels in a straight line,” says Charles Gerba, a microbiologist at the University of Arizona. “So it won’t get under a table top, for example,” he says. Uneven surfaces also may not be uniformly sanitized.

There have been lots of studies to confirm the addition of high-powered UV rays in hospital settings, says Gerba. For example, it has been shown to effectively reduce microbes by up to 99 percent on hospital keyboards and it has reduced the presence four major drug-resistant superbugs by 30 percent. But, says Gerba, there has been no verification of how effective they are in restaurant settings. The same is true for antiviral coatings, he adds.

“I’m not saying it’s not potentially useful, but it hasn’t been verified in restaurants,” he says. He worries some restaurant owners could be overconfident in UV light’s ability to reduce the risk of COVID-19.

Welch says the overwhelming majority of UVC lamps available right now can cause eye and skin damage, so they should not be used when there is a danger of being exposed. “There are a number of falsely advertised products available right now, especially for products claiming to be far-UVC lighting,” he notes. “If the wrong lamp is installed or if UV lights are installed incorrectly there are potential health risks—not to mention they may not be effective.”

Warriner agrees. “Depending on the system, anything less than a 12-watt output is going to have limited effect,” says Warriner. “If the lamps are uncovered [exposing humans to the light] then you know for sure it is not legitimate,” he says.

When it comes to restaurants, making sure the air is free of COVID-19 may be of special concern. A CDC epidemiological study from a restaurant in Guangzhou, China, found that air currents moved by an air conditioning vent in a crowded restaurant helped spread the virus. The study showed that sitting in the direction air was flowing posed a significant risk, resulting in as many as eight diners contracting the coronavirus.

Gerba has no concerns with the use of UV light to sanitize air moving through heating, venting, and cooling (HVAC) systems. Warriner suggests that UV used with a high efficiency particulate air (HEPA) filter is an even better system. In an HVAC system, the microbes could pass over the lamp too quickly to be inactivated, but a filter system, such as HEPA, enables the microbes to be trapped and then inactivated, says Warriner.

Using UV Light Beyond Restaurants

Beyond restaurants, other food service businesses are exploring UV light for sanitation. The Summerhill Market in Toronto, Canada, recently tested the XGerminator, a new tunnel-like device to sanitize groceries in the checkout line. Using high-dose 254 UVC to kill any microbes before shoppers take them home, their tests revealed that lower doses would be sufficient. The XGerminator is being developed in partnership with Prescientx, an Ontario, Canada-based company that produces UV devices for the healthcare industry.

The eventual device, which they expect to be available first in Canada in about three months, will have multiple levels of safety to ensure that at no time the checker or bagger be exposed to UVC, says Keith McGlone, a vice president at Prescientx.

McGlone shares safety concerns about the bevy of products coming on the unregulated UV market at the moment, including a personal handheld device. “There’s a lot of strange stuff being thrown out there—like UV wands,” he says. He advises consumers interested in such products to deal with companies who have been in the UV business for a while and are members of the International UV Association.

“We’re still learning more about how COVID-19 is spread . . . so it’s really tough to predict the specific effectiveness,” says Welch. “But UV is an important tool that can be part of the overall protection plan.”