The Microbial Load on Used Disposable Face Masks: Exploring Sustainable Disinfection Methods

Face masks have become common-place in public settings since the onset of the global COVID-19 pandemic, with many people choosing to wear masks in order to mitigate the risk of becoming infected with viral or bacterial infections. Two of the most widely-available types of masks are cloth masks, which may be reused if cleaned properly, and disposable surgical masks. Despite the fact that surgical masks are intended for one-time use, many people chose to store and re-wear them. The purpose of this study was to determine the changes in biological contamination on surgical face masks after daily wear and overnight storage. This was assessed by measuring the microbial contamination on the interior and exterior surfaces of the used surgical masks before and after overnight storage. Adenosine Triphosphate (ATP) bioluminescence was measured on the masks as a marker of microbial life. A luminometer device was used to quantify the ATP levels as Relative Light Units (RLU). The average ATP level on the face masks immediately after wear was 136.8 ± 90.99 RLU/cm² on the interior and 58.41 ± 46.01 RLU/cm² on the exterior. The results of this study showed there was evidence of a significant difference between microbial contamination on the interior and exterior surfaces of the masks (P0.01) at a 99% confidence level. These results supported the existing standard that disposable face masks should not be re-worn without any kind of disinfection. Additional trials were conducted during this study to determine how the presence of camphor would affect ATP levels during incubation