The Formation Characteristics Of The Biofilm Of Vibrio Parahaemolyticus And The Scavenging Effect Of Disinfectants

This paper mainly studies the biofilm formation ability of pathogenic and non-pathogenic Vibrio parahaemolyticus under different environmental conditions and 6 kinds of disinfectants on cleaning the biofilm was assessed.We can selected effective disinfectant,it provides a theoretical basis for further optimizing the control strategy of biofilm in the food industry.V.parahaemolyticus isolated from different aquatic products and 10 pathogenic V.parahaemolyticus donated by Dalian disease prevention and control center were isolated and identified.The results showed that 16 strains of V.parahaemolyticus were isolated from 48 aquatic products,and the detection rate was 33.3% and showed only tlh positive while tdh,trh,torRS/new and orf8 were all negative by PCR.The 16 environmental strains were all non-pathogenic V.parahaemolyticus.10 pathogenic V.parahaemolyticus tdh were positive,torRS/new was negative,only 1 strains carried the trh gene,and 6 strains carried the orf8 gene.It is not easy to isolate V.parahaemolyticus with pathogenic factors in the environment,and tdh is the main pathogenic factor of clinical strains.Study of influence of different environmental factors on the biofilm formation of V.parahaemolyticus.Biofilm formation of 26 strains of V.parahaemolyticus was studied using microplate methods under the different temperature and medium conditions,and the best biofilm formation strains were chosen for the further study at different NaCl concentrations and pH.The results showed that the biofilm formation ability of 26 strains of V.parahaemolyticus from different sources was different under different temperature and media conditions,showing the specificity and diversity of strains.Compared with 13 ?,22 ? is more conducive to the biofilm formation of the strains.At the same time,the biofilm formation ability of the strains in TSB was better than the strains in the M9 medium.The strains of E11,E17 and 156 FR form strong biofilm.Therefore,in subsequent experiments,the selected original culture conditions were high nutrient TSB medium,and the temperature was 22 ?.The selected strains were non-pathogenic strains E11,E17 and pathogenic strain 156 FR.Both pathogenic and non-pathogenic strains showed strong biofilm formation ability at NaCl concentration of 1.5%-5.5%.When NaCl concentration was 0.5%(low salt concentration)or 7.5%-9.5%(high salt concentration),it was not conducive to biofilm formation.The optimum pH value is 7-8,which is not conducive to the formation of biofilm under the condition of acid or alkaline.Effects of different culture conditions of E17 and 156 FR swimming ability.The results showed when the temperature is 37 ?,the concentration of NaCl was 1.5%-5.5%,pH value of 7-8,V.parahaemolyticus has obvious swimming behavior.Too high or too low temperature,NaCl concentration and pH can inhibit the swimming activity.The study of three categories of 6 kinds of disinfectants,including quaternary ammonium salts(benzalkonium chloride),peroxides(chlorine dioxide,peracetic acid and hydrogen peroxide)and chlorine(sodium dichloroisocyanurate and sodium hypochlorite),scavenging effect on E17 and 156 FR biofilm,the changes of biofilm and morphology were observed by scanning electron microscope before and after disinfection.The results showed that among 6 disinfectants sodium dichloroisocyanurate and sodium hypochlorite were the most effective with the removal rate more than 90% under 50 mg/L sodium dichloroisocyanurate for 10 min and 30 mg/L sodium hypochlorite for 5 min.Under scanning electron microscope,30 mg/L sodium hypochlorite was observed to clear all the biofilms after disinfection of 20 min,and the bacteria were dry and dead.