高静压对枯草杆菌芽孢灭活作用的研究

Effects of high-hydrostatic pressure on inactivation of Bacillus subtilis spores

采用高静压协同中温的方法,研究了连续式施压(continuous pressurization)和间歇式施压(intermittent pressurization)两种不同方式对枯草杆菌芽孢的灭活作用。实验设计了分阶段施压方式,即先低压200MPa/5min,再高压500MPa/5min,循环1～3次。结果表明,同200MPa～500MPa连续施压30min相比,间歇施压更有效地杀灭芽孢,并缩短了处理时间。经扫描电镜观察,芽孢外壳出现凹陷、皱褶等形态变化,这种间歇式的施压产生强烈的机械剪切力,造成芽孢损伤,及内容物的泄漏,甚至死亡。

In order to investigate the effects of high-hydrostatic pressure on the inactivation of B. subtilis spores, a two- step intermittent pressurization （IP） treatment was designed beginning with a lower pressure （200 MPa at 45 12 ） treatment for 5 min, followed by higher pressure （500 MPa at 45 12 ） for another 5 min. This process was repeated up to three times. After IP treatment, scanning electron microscopy observation showed that spores were morphologically concave and even disrupted. The leakage of proteins and nucleic acids from B, subtilis spores increased, compared with that of a continuous pressurization treatment. These results indicated that IP treatment generated a mechanical impact force, which led to the injury of bacterial spores and leakage of their contents, and that was crucial for their inactivation. The intermittent pressurization treatment saved time and required a lower temperature. Therefore, it could be an effective means for inactivating bacterial spores in food preservation.