Plasma-activated water effectively decontaminates steamed rice cake

Abstract

This study investigated the effects of plasma-activated water (PAW) treatment parameters on the inactivation of indigenous mesophilic aerobic bacteria and coliform bacteria on steamed rice cake (SRC). PAW treatment was conducted by washing SRC with PAW, prepared by treating sterilized distilled water with surface dielectric barrier discharge plasma at 16 kV. The plasma discharge time and SRC mass significantly affected the efficacy of microbial inactivation. The optimum treatment conditions (28.7 min of discharge time, 29.0 min of treatment time, and 155.5 g of SRC) did not alter the color and firmness of the SRC. The results demonstrated that the antimicrobial activity of PAW was more due to the presence of plasma reactive species than due to low pH. Furthermore, PAW treatment inhibited the growth of indigenous mesophilic aerobic bacteria much more effectively than NaClO (0.2 g/L) solution treatments. This study demonstrated the potential of using PAW treatment to improve the microbiological stability of SRC.