Efficacy of Bioshell Calcium Oxide Water as Disinfectants to Enable Face Mask Reuse.

Hiruma, Sumiyo; Hata, Yuuki; Ishihara, Masayuki; Takayama, Tomohiro; Nakamura, Shingo; Ando, Naoko; Fukuda, Koichi; Sato, Yoko; Murakami, Kaoru; Yokoe, Hidetaka

Bioshell calcium oxide (BiSCaO) is derived from scallop shells and after heat treatment exhibits broad microbicidal activity. BiSCaO Water is a disinfectant prepared by collecting the aqueous layer after adding BiSCaO powder to water, is colorless and transparent, and has a pH of 12.8. We compared the utility of commercially available BiSCaO Water, ethanol, sodium hypochlorite, hypochlorous acid and hydrogen peroxide solutions as sterilization agents to enable the reuse of surgical and N95 face masks. The microbicidal efficacy of each disinfectant was evaluated using pieces of surgical and N95 face masks contaminated with normal bacterial flora. The results suggest that BiSCaO Water has excellent disinfection activity toward contaminated polypropylene masks and has minimal adverse effect on the structure of non-woven masks.