Inactivation Treatment of Bacterial Spores Contaminated Spices by Atmospheric Plasma Jet

Spices are often added to various food products to utilize their flavor and aroma. The microbial contamination of imported spices has been causing problems in the food industry. Microbial spores of Bacillus species are the common contaminant in many spices. We performed inactivation processing using an atmospheric pressure plasma jet to achieve efficient inactivation of microorganisms for thermosensitive materials such as spices. Based on the results of calorimetry, the growth rate constants of plasma-irradiated black pepper were relatively smaller than those of untreated spices, and the retardation in growth of argon + carbon dioxide plasma-irradiated black pepper was extraordinarily larger than that of untreated spices, as was the growth rate constants. Based on sterility tests, the microorganisms attached to the spice could be sterilized by 5-minute treatment with an argon + carbon dioxide atmospheric plasma jet.