电子束辐照对李斯特菌生理特性的影响

Effect of Electron Beam Irradiation on Physiological Character of Listeria innocua

以英诺克李斯特菌为研究对象,探讨了不同电子束辐照剂量(0.00、0.75、1.50、2.25、3.00、3.75、5.00 kGy)对李斯特菌的灭活作用和生理状态(包括细胞膜通透性、胞内离子泄漏量、Na^+K^+-ATP酶和Ca^(2+)Mg^(2+)-ATP酶活性、膜电位、菌悬液pH值)的影响。结果显示:经5.00 kGy电子束辐照后,李斯特菌菌落总数(N)的对数lg N由对照组的8.9降至5.00 kGy时的1.4,D_(10)=0.69 kGy,杀菌效果显著。随着剂量的增加,细胞膜通透性显著增大、胞内离子(K^+、Ca^(2+)和Mg^(2+))泄漏量显著增加、Na^+K^+-ATP酶和Ca^(2+)Mg^(2+)-ATP酶活性显著降低、膜电位及菌悬液pH值显著下降。以上结果表明,电子束辐照造成李斯特菌生理代谢紊乱,从而加速菌体的死亡。

Listeria innocua was used to investigate the effects of different electron beam irradiation dosages (0.00, 0.75, 1.50, 2.25, 3.00, 3.75 and 5.00 kGy) on the inactivation and physiological status of Listeria innocua (including cell membrane permeability, leakage of intracellular ions, activity of Na^+K^+-ATPase and Ca^2+Mg^2+-ATPase, membrane potential, pH of bacterial suspension). The results show that the logarithm of total number of Listeria innocua decreases from 8.9 to 1.4 after 5.00 kGy electron beam irradiation with D10=0.69 kGy, and the bactericidal effect is significant. With the increase of dosage, the cell membrane permeability and the leakage of intracellular ions (K^+, Ca^2+ and Mg^2+) increase significantly. The activities of Na+K+-ATPase and Ca^2+Mg^2+-ATPase decrease significantly, and membrane potential and the pH of bacterial suspension also decrease significantly. According to the above results, electron beam irradiation causes the disorders of physiological metabolism of Listeria innocua, which accelerates the death of the bacteria.