감압 플라즈마를 이용한 Escherichia coli 살균

Low-pressure plasmas (LPPs) were generated with different gases such as air, oxygen and nitrogen, and their inactivation effects against Escherichia coli were compared in order to evaluate the potential as a non-thermal microbial disinfection technology. Homogeneous plasmas were generated under low pressure below 1 Torr at gas flow rate of 350 mL/min regardless the types of gases. Temperature increases by LPPs were not detrimental showing less than 10°C and 25°C increases after 5 and 10 min treatments, respectively. The smallest temperature increase was observed with air LPP, and followed by oxygen and nitrogen LPPs. More than 5 log reduction in E. coli was achieved by 5 min LPP treatment but the destruction effect was retarded afterward. The LPP inactivation was represented by a biphasic first order reaction kinetics. The highest inactivation rate constant was achieved in air LPP and followed by oxygen and nitrogen LPPs. The small D-values of the LPP also supported its potentialities as a non-thermal food surface disinfection technology in addition to the substantial microbial reduction of more than 5 logs.