Microbiostatic effect of indoor air quality management with low-concentration gaseous chlorine dioxide on fungal growth

Biological contamination of fresh produce by fungi in storage is becoming a serious problem. Gaseous chlorine dioxide (ClO₂) has been used to prevent fungal growth on fresh produce; however, the specific effects of gaseous ClO₂ at concentrations low enough to be safe for the human body on fungal growth remain unknown. Therefore, in this study, we aimed to investigate the effect of low-concentration gaseous ClO₂ on fungal growth in sweet potatoes over 1 month. Here, a mechanochemical reaction involving the collision of two types of powders was used to produce low concentrations of gaseous ClO₂. The experiment was conducted in a container and chlorine dioxide gas was diffused by a circulator to verify its microbiostatic effect in a large space. A clear microbiostatic effect was observed in potatoes without skin when exposed to low-concentration ClO₂ for 3 days. Notably, low concentrations (< 1.0 ppm) of ClO₂ reduced Rhizopus stolonifer growth in sweet potatoes with skin over 1 month. Therefore, low concentrations of gaseous ClO₂ are sufficient to inhibit fungal growth via gas diffusion.