Research Of Sterilization Effect And Mechanisms Of Plasma-activated Water On P.deceptionensis Isolated From Chicken Meat

Plasma activated water（PAW）,a non-thermal processing technology,is produced by plasma discharge in water surface or under water.PAW,prepared by the plasma discharge treatment of sterile distilled water（SDW）at 30,60,and 90 s,was defined as PAW30,PAW60,and PAW90,respectively.In this work,a strain spoilage organism（P.deceptionensis CM2）isolated from chicken meat was used as the target microorganism.The effects of PAW on the inactivation of P.deceptionensis CM2 and the quality of chicken breast were investigated.Meanwhile,the biological mechanism of PAW against P.deceptionensis CM2 was revealed.Based on the above research,the effects of food components on the bactericidal effect and mechanism of PAW were simulated by adding organic matter（peptone and beef extract）to PAW,which provided a theoretical basis for the application of PAW sterilization technology in food industry.The main research results were as follows:（1）Effect of PAW on surface sterilization and quality of chicken breast.Compared with the control group,the PAW treatment can significantly decrease the number of P.deceptionensis CM2 on the surface of chicken breast（p<0.05）.After being treated with SDW and PAW60,the L*value of samples increased whereas a*and b*values decreased in comparison to the control group.Following the treatment of SDW and PAW60,there were no significant changes in the texture and sensory characteristics of the chicken breast（p>0.05）.However,SDW and PAW60 also did not significantly affect pH value of chicken breast after3-9 min treatment（p>0.05）.It shows that PAW has not only inactivation efficiency against P.deceptionensis CM2 on the surface of chicken breast,but also slight effect on the quality of chicken breast.（2）Effect of PAW on the inactivation efficiency and mechanism against P.deceptionensis CM2 in pure culture.With the increasing of PAW60 treatment time,the viable count and average cell size of P.deceptionensis CM2 decreased significantly（p<0.05）,cell membrane permeability increased,and bacterial cells ruptured.With the increasing of plasma activation time,the pH in PAW30,PAW60,and PAW90 decreased significantly（p<0.05）,and the contents of ORP,H₂O₂,NO₂^-,and NO₃^-increased significantly（p<0.05）.Therefore,the synergistic effect of the main active substances and low pH may affect the sterilization effect of PAW against P.deceptionensis CM2.（3）Effect of peptone and beef extract on the inactivation efficiency and mechanism of PAW.With the increasing of two organic concentrations（0 g/L,0.5 g/L,1.0 g/L,2.5 g/L,and5.0 g/L）,the bactericidal effect of the mixture of PAW60 and organic matter against P.deceptionensis CM2,E.coli O157:H7,and S.aureus were significantly decreased（p<0.05）,and the pH of the mixture of PAW60 and organic matter increased while ORP and NO₂^-content decreased,but H₂O₂ content did not change significantly（p>0.05）.It shows that the addition of organic matter has reduced the bactericidal effect of PAW.