超临界CO2作为一种新型的非热杀菌技术受到普遍关注,但其杀菌机理尚未揭示清楚。文中研究了腐生酵母菌经超临界CO2杀菌处理后,细胞内外pH值的变化,并探讨了细胞内外pH值的变化与菌体死亡的关系。结果表明:经过10 MPa、37℃的超临界CO2处理,细胞外的pH值逐渐降低,细胞内pH值呈现先下降,后上升,又略微下降的趋势。在超临界CO2处理过程中,细胞外pH值的降低并不是导致细胞死亡的直接因素,但可以间接提高杀菌效果;胞内pH值的变化,扰乱了细胞的正常代谢功能,是导致细胞死亡的重要因素。

As a new non-thermal sterilization technology,supercritical carbon dioxide(SCCO2) draws the attention of the public.But the mechanism of microbial inactivation has not been clearly explained.In this study,the extracellular and intracellular pH of a saline solution of saprophytic yeast treated by SCCO2 was determined.The correlation between pH and death rate under SCCO2 was also been discussed.The results indicated that the extracellular pH declined,but the intracellular pH first decreased,then increased,and declined slightly.The decrease of extracellular pH induced by SCCO2 was not the direct factor of death rate,but helped improve the sterilization effect.The change of intracellular pH induced by SCCO2 was the key factor of cell death.