| Biocides are often used to disinfect the environment and equipment in industrial production.However,single chemical biocide expressed limited effect on phage inactivation.Evaluation of the combined inactivate effect of multiple biocides on phage may provide effective basis for the establishment of phage defense systems in industry.In this study,the combined inactivate effect of ethanol and other biocides(isopropanol,sodium hypochlorite and peracetic acid)with different concentrations on Lactobacillus bacteriophage P1 and P2 were evaluated.Moreover,three compound methods were used,including directly mixing the biocides and treated for 10 min;treated by ethanol solution for 5 min followed by other biocide for 5 min;treated by other biocide for 5 min followed by ethanol solution for 5 min.The results were listed below.(1)Combined biocides can inactivate Phage P1 and Phage P2 effectively.It can meet the requirements of commercial sterilization,reduce the cost,and guarantee the stability of related product.(2)Lactobacillus phage P1 can be totally inactivated by the mixture of 100% isopropyl alcohol and 100% ethanol for 10 min.Lactobacillus phage P2 can be totally activated by 100 % ethanol treated for 5 min followed by 5 min 100% isopropanol treatment,vice versa.(3)800 ppm sodium hypochlorite for 5 min followed by 20% ethanol treated for 5 min,or 75% ethanol for 5 min followed by 400 ppm sodium hypochlorite,or 800 ppm sodium hypochlorite treated for 5min followed by 5 min 75% ethanol treatment can inactivate phage P1 completely.Lactobacillus phage P2 can be totally inactivated by either 200 ppm sodium hypochlorite treated for 5 min and then inactivated 5 min by 75% ethanol or 200 ppm sodium hypochlorite followed by 100% ethanol.(4)The combination of ethanol and peracetic acid can not inactivated these two phages completely.For phage P1,100% ethanol followed by 0.45% peracetic acid only resulted in 3.16 log reduction.For phage P2,it only caused 3.84 log reductions. |
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