Another Possible Disinfecting Use for UV Light Found

Ultraviolet-C light makes benzalkonium chloride, which is found in many disinfectants, safer to use.

Applying germicidal ultraviolet-C (UVC) light to common disinfectants could make them safer to use and could also help them to better fight COVID-19, according to investigators with the University of Waterloo in Ontario, Canada.

Results from their study were published in the journal Cutaneous and Ocular Toxicology.

“With concerns about the spread of COVID-19, people are utilizing products with BAK as an active ingredient more than ever,” said Manlong Xu, the study’s lead author. “For many industries, there is the demand to improve the efficacy of standard disinfection procedures, while also keeping in mind any potential negative impact on the environment.”

Benzalkonium chloride (BAK), one of the most common active ingredients in many disinfectants that are used in households, food processing plants and hospitals, cannot be used in high concentrations due to its toxicity.

However, in order to protect against harmful viruses and bacteria, high concentrations of BAK are needed, and the residue can harm the environment and people.

For the study, investigators exposed a BAK solution to UVC lamps and then applied the solution to cultured human corneal cells. After 5 minutes, they analyzed the cells for metabolic activity, as well as viability, and found that the BAK solution was neutralized by the UVC and did not harm the cells.

“Our results show that a disinfecting procedure using BAK followed by UVC radiation can minimize the harmful effect of BAK residues on humans and the environment,” David McCanna of Waterloo's Department of Optometry & Vision Science said. “Such a procedure also has a great potential to maximize the disinfection efficacy by utilizing two different antimicrobial mechanisms. As the pandemic continues, our findings are especially important as it provides another method to make our hospitals, food, homes, and the environment safer.”

This story originally appeared in Contagion®.