Microwave Sterilization Mechanism Overview
    Microwave sterilization with high efficiency, speed, processing pollution, etc., thus increasing people 's attention. But the existence of non-thermal microwave sterilization effect is still controversial , sterilization mechanism remained open . In this study, black variant of Bacillus subtilis ATCC9732, E. coli BL21 and Metarhizium IMl330189 for the test strains , the use of domestic microwave radiation, from the following four aspects: ( 1 ) the existence of non-thermal effects of microwave ; ( 2 ) microwave structure of the cell surface ; ( 3 ) microwave on cell permeability ; ( 4 ) microwave impact on microbial DNA mechanism of microwave sterilization . In order to apply microwave sterilization fungal preparation production line , as well as guided microwave equipment to provide a scientific basis and related technical parameters . The results reported below :
    ( A ) Effect of microwave sterilization
    By direct microwave field , microwave and copper mesh shielding Three methods for heating water bath Bacillus subtilis black variant comparison test study . The results showed that after microwave treatment directly black variant of Bacillus subtilis bacteria residual values ​​and bactericidal D values ​​( to kill 90% of the time by microorganisms ) were lower than copper shield and microwave heating treatment bath ; different time microwaved residual bacteria on the fastest decline in value . It can be seen in addition to microwave heating effect , but also the presence of non-thermal effects .
    ( 2 ) the role of the microwave field effect on the cell surface structure
    Against spores, vegetative cells were subjected to microwave , microwave and copper mesh shielding heated water bath . Treatment, electron microscopy showed that : Microwave treatment group , part of the spore cell wall rupture, leakage of contents , a few showing a hollow shell ; vegetative cell deformation, folds, some cells showed a bent shape, severely damaged the cell adhesion into blocks . Copper mesh shielding microwave treated group and the water bath , cells without significant deformation . The results showed that the microwave has damaging effects on the microbial cell wall .
    ( 3 ) the role of the microwave field effects on cell permeability
    Black variant of Bacillus subtilis ATCC9732 broth separately microwave treatment , copper mesh shielding microwave treatment , water bath treatment, determined using Coomassie blue soluble protein leakage detection cell permeability changes. The results showed that all three treatments can be somewhat changed cell wall / I membrane permeability , resulting in leakage of cell contents ; 3 different treatment methods , the microwave leakage treated cells most of the soluble protein , Description microwave treatment on microbial permeability strongest.
    ( 4 ) the microwave field effects on microbial nucleic acids
    The test strains black variant of Bacillus subtilis , Escherichia coli and Metarhizium anisopliae for three kinds of treatment: a microwave field radiation test strains after extracting DNA, running electrophoresis ; 2 , extracted black variant of Bacillus subtilis , E. coli DNA after microwave radiation, direct run electrophoresis ; 3 , microwave radiation Metarhizium anisopliae , the extraction of DNA as a template for PCR amplification run electrophoresis . The results showed that use of l, 2 kinds of methods after treatment , DNA electrophoresis bands dispersion , is missing. After treatment using the third method , DNA bands amplified product was weak, is missing. The results showed that the microwave field microbial DNA structural damage caused by radiation , which is one cause of death of microorganisms microwave ; second method results showed that after treatment , this injury related to temperature .