Abstract
In the food industry, it is an important issue to prevent secondary contamination by airborne and attached microorganisms. Considering recent respiratory infections such as the influenza virus and the current Covid-19 Pandemic, controlling pathogens in indoor spaces has been emphasized. Especially the transmission of the virus indoors is a major concern. Hypochlorous acid (HOCl) has so far been used as a liquid-based disinfectant for treating things. Recently, the scope of objects to be treated with hypochlorite solution has been expanded to indoor spaces, including air and solid surfaces, and the use of gaseous hypochlorous acid (HOCl(g)) has been studied intensively. Safe utilization of HOCl(g) requires appropriate control and management of its concentration. It has been demonstrated that HOCl(g) is an effective disinfectant against various bacteria and viruses, including SARS-CoV-2, in aerosols and solid surfaces at low concentrations. The bactericidal efficacy of HOCl(g) depends on the product of the HOCl(g) concentration and time, and it increases with increasing the relative humidity. The use of HOCl(g) is of potential advantage to inactivate harmful microorganisms present in large indoor spaces without wetting the surface and without manual manipulation, i.e., no touch techniques. There are no safe disinfectants without accurate control of their concentration. It is crucial to imaginatively consider how to use HOCl(g) for the safe and effective disinfection of various settings for the foreseeable future.
