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Do personal UV disinfectant lights really kill harmful bacteria?

HOUSTON – Since the start of the coronavirus pandemic, we’ve seen a ton of ultraviolet light devices hit the market, claiming to disinfect surfaces and items in and around your home. But do they work? We purchased two and put them to the test.

A little background

UV lights have been used for decades to disinfect surfaces and water treatment plants, even hospitals. The technology isn’t new and it’s proven to work. But small, personal UV devices are only now becoming mainstream, and the industry is entirely unregulated.

The products we tested

  • We purchased the Safe & Healthy UV Disinfecting Light at Walmart for $19.88. It claims you can scan anything for 10 seconds to kill 99.9% of viruses and harmful bacteria on the surface. To be honest, the product, a small wand, feels cheap. We weren’t expecting much.
  • We purchased the Samsung Electronics Wireless charger box on Amazon for $49.99. It claims to charge your Samsung cell phone and kill 99.99% of bacteria on your phone at the same time. The device is a small box. It claims that it will disinfect anything you can fit inside, like keys, jewelry or small toys in about 10 minutes.

The Test

Since we can’t see the germs and bacteria, we took the devices to Tanny Busby at Environdyne Laboratories, Inc in southwest Houston.

Lab technicians swabbed a phone and cultured the swab to see just how much bacteria was on the device. They then took the bacteria on the petri dish and scanned it with the Safe & Healthy UV Disinfecting Light for 10 seconds.

They put another petri dish inside the Samsung Electronics Charging box. Within 48 hours, you could see how many of the bacteria cultures the UV devices killed.

The Results

Safe & Healthy UV Disinfecting Light: Busby said this device was “very effective” at wiping out 99.9% of the bacteria on the petri dish. You could see a noticeable difference on the dish that was scanned when compared to the culture that was not scanned by the UV light.

Samsung Electronics Wireless charger box: This device showed hardly any reduction in the bacteria or e-coli on the petri dish.

What’s the difference?

Busby said the biggest difference in the two products is where the UV light actually hits the product you need to disinfect. The UV lights in the box are just on the sides. That means they don’t hit all areas of the phone you would want clean.

“Maybe perhaps if the light was on top of the lid, facing down with more contact time, I think we’d get a little bit better results,” said Busby.

Conclusion

The UV lights do work to kill bacteria and germs (even the cheap ones) but you have to make sure the UV light is coming into close contact with the surface of whatever you want to disinfect. Consider that when you are buying one.

It is also important to note that these personal UV devices are not regulated. They can also be very dangerous if you shine the light into your eyes or on your skin.