Study On The Bactericidal Mechanism Of Acidic Electrolyzed Water And Its Application Analysis

Acidic electrolyzed water is a new kind of disinfectant water developed by Japan.It caused great attentions in the fields of food processing,agricultural products preservation,and prevention of agricultural diseases due to its high efficiency bactericidal and environmental protection effect.At present,some researchers used acidic electrolyzed water to inactive foodborne pathogens in pure culture.Results showed that acidic electrolyzed water can exert strong bactericidal ability to the common foodborne pathogenic bacteria such as Listeria monocytogenes,Vibrio parahaemolyticus,Escherichia coli,Salmonella and so on.In addition,some researchers used acidic electrolyzed water to treat fresh cut vegetables and fruits,marine meat and other agricultural products.Results showed that acidic electrolyzed water could guarantee the safety of food quality effectively,so as to meet the consumption demand of modern consumers.However,current researches about acidic electrolyzed water only stays at the evaluation level of sterilization and preservation effect,and its mechanism of sterilization and preservation is still unclear.Therefore,in this work,two common food borne pathogens were selected as the research object and aseptic tap water was used as a control.Firstly,investigated the bactericidal effect of acidic electrolyzed water towords Vibrio parahaemolyticus and Listeria monocytogenes by counting the number of living bacteria,observing the microstructure of bacteria,monitoring the level of protein leakage and observing the degree of DNA degradation in the bacterial genome.Secondly,specific injured sites of Vibrio parahaemolyticus and Listeria monocytogenes were investigated through metabolic inhibitors.Thirdly,at the transcriptional level,the expression of injured sites related genes were explored.The aim was to reveal the bactericidal mechanism of acidic electrolyzed water.Finally,on the basis of the study of the bactericidal mechanism of acid electrolysis water,the application ability of the bactericidal action of acid electrolysis water in the actual production and life is analyzed.The theory and practice are combined to provide the theoretical basis for the future application of acidic electrolyzed water in more fields.1.Study on the bactericidal effect of acidic electrolyzed water on Vibrio parahaemolyticus and Listeria monocytogenesIn this chapter,the bactericidal effect of acidic electrolyzed water on Vibrio parahaemolyticus and Listeria monocytogenes bacteria was studied by plate coating,scanning electron microscopy,BSA experiment and gel electrophoresis.The results showed that after the treatment of AEW1(0.1% Sodium Chloride Solution electrolysis 5min),the number of viable Vp.ATCC17802 strains decreased 1.55 log CFU/ml,and the number of sublethal damage was 0.69 log CFU/ml.The number of viable Vp.O3:K6 strains decreased 1.27 log CFU/ml,and the number of sublethal damage colony was 0.54 log CFU/ml.Strains Lm.ATCC19115 reduced 1.05 log CFU/ml,and the number of sublethal damage colony was 0.19 log CFU/ml.After AEW2(0.1% Sodium Chloride Solution electrolysis 15min)treatment,Numbers of living bacteria of two strains of Vibrio parahaemolyticus were all negative.Strain Lm.ATCC19115 decreased by 1.16 log CFU/ml,and the number of sublethal damage was 0.38 log CFU/ml.Scanning electron microscopy(SEM)showed that untreated Vibrio parahaemolyticus and Listeria monocytogenes had regular morphology and intact cell membrane.The structure of Vibrio parahaemolyticus and Listeria monocytogenes was collapsed when bacteria were treated by acidic electrolyzed water,and with the increase of acid electrolysis water concentration,the cell morphology was disintegrated seriously and the shape of bacteria was blurred.The gel electrophoresis and BSA results showed that the genomic DNA bands of untreated Vibrio parahaemolyticus and Listeria monocytogenes was clear and bright,while with AEW treatment,the genomic DNA bank was dark,and the strip became shallow with the increase of the acid electrolysis water concentration.In addition,under the same concentration of acidic electrolyzed water treatment,the DNA degradation of was more obvious than that of Listeria monocytogenes.Additionally,acidic electrolyzed water treatment caused protein leakage in cells,and with the increase of electrolyzed water concentration,the protein leakage is more serious.2.Study on the bactericidal target of acidic electrolyzed water towards Vibrio parahaemolyticus and Listeria monocytogenes.Based on the study of the second chapter,bactericidal targets caused by acid electrolyzed water were located antibiotics.The results showed that the acid electrolysis water treatment could cause the cell wall injury of Vibrio parahaemolyticus and Listeria monocytogenes,protein synthesis was inhibited and the RNA polymerase was inactived.3.The expression of genes related to injured sites of Vibrio parahaemolyticus and Listeria monocytogenesIn this chapter,q-PCR was used to investigate the gene expression at the destruction site caused by acidic electrolyzed water.The results showed that the expression of protein synthesis related genes(Phes,RPLJ)were down regulated after acidic electrolysis water treatment,the expression of RNA synthesis related gene(RPOD)was down regulated,and the expression of murA related genes was up-regulated,and the expression of genes related to oxidative stress was up-regulated.In conclusion,acidic electrolyzed water can kill bacteria by destroying the cell wall,ribosome large subunit and RNA polymerase.4.Application analysis of acidic electrolyzed water in storage and transportation of aquatic productsThis chapter taking the Penaeus vannamei as the research object,then analyzed the application of acidic electrolyzed water in the storage of aquatic products in the form of ice.Results found that acidic electrolyzed water ice could significantly inhibit the growth of total bacteria during the ice preservation of Penaeus vannamei.Through 16 sRNA sequencing,acidic electrolyzed water ice could significantly reduce the relative abundance of two kinds of spoilage bacteria including genus Psychrobacter and Shewanella.Furthermore,acidic electrolyzed water could effectively maintain the microbial diversity of Penaeus vannamei.In addition,the treatment of acid electrolysis water ice can effectively inhibit the change of pH and the accumulation of volatile base nitrogen in the fresh preservation process of Penaeus vannamei,which helps to maintain the quality of shrimp meat.