The objective of this study was to determine the optimal disinfection treatment conditions of dielectric filter discharge (DFD) plasma against aerosolized pathogens relevant to edible insect-rearing environments. Bacillus thuringiensis, Serratia marcescens, and Escherichia coli O157:H7 are representative pathogens that can occur in edible insect-rearing environments. This study employed a treatment scheme in which plasma was applied during nebulization to treat aerosolized pathogens, after collection to treat filter-attached pathogens, or sequentially to both (overall pathogens). Negligible or minimal bactericidal effects were observed when DFD plasma was applied to aerosolized or filter-attached pathogens for 2 min. However, continuous treatment of both for 2 min each (a total of 4 min) resulted in significant inactivation, and longer treatment times (10 min) for filter-attached pathogens further enhanced the bactericidal effect (2.6~3.4 Log CFU/cm² reduction). No bactericidal effect was observed during storage after DFD plasma was turned off. Consequently, the highest bactericidal effect was obtained when DFD plasma was applied to aerosolized pathogens for 2 min, followed by an additional 10 min of treatment with filter-attached pathogens. These results indicate the potential use of DFD plasma for disinfecting aerosolized pathogens in edible insect-rearing environments.
Yeo et al. (Wed,) studied this question.