Abstract:To improve the control effect of electron beam irradiation on foodborne pathogens, the effects of electron beam irradiation on the growth of pathogenic bacteria were studied by analysis of D10 value, growth curve, biofilm formation and dominant bacteria in mixed culture of four common foodborne pathogens, including Escherichia coli, Salmonella typhimurium, Listeria monocytogenes and Bacillus cereus. The results showed that electron beam irradiation had strong disinfecting influence on these four pathogens and theD10 values ranged from 0.330 kGy to 0.648 kGy. In addition, multiple irradiation could decrease the D10 values, leading to the lower tolerance of pathogenic bacteria to irradiation. Sublethal dose electron beam irradiation could inhibit bacterial growth, which shoD10wed longer lag phase and lower colony quantity level of stationary phase than that of the control. And this effect was especially significant at lower temperature of 15 ℃. Among different pathogenic bacteria, Escherichia coli was the most sensitive to irradiation, with the lowest D10 valueand the greater lag degree of lag phase than other pathogenic bacteria, while Bacillus cereus was the least sensitive to irradiation. When the four pathogens were mixed and co-cultured after irradiation, the growth of Bacillus cereus irradiated by electron beam was inhibited and the percentage decreased from 33.49% to 25.06%, while the percentage of other three pathogens increased. Sublethal dose electron beam irradiation could affect the biofilm formation of pathogenic bacteria. After irradiation, the ability of forming biofilm of Escherichia coli and Bacillus cereus was enhanced, while that of Salmonella typhimurium or Listeria monocytogenes was weakened.
