Reyns Kristien M F A, Veraverbeke E A, Michiels C W
Laboratory of Food Microbiology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, B-3001 Leuven, Belgium.
J Food Prot. 2003 Jun;66(6):1035-42. doi: 10.4315/0362-028x-66.6.1035.
The effect of high hydrostatic pressure treatment (with pressures of up to 700 MPa) on Talaromyces macrosporus ascospores was investigated. At 20 degrees C, pressures of > or = 200 MPa induced the activation and germination of dormant ascospores, as indicated by increased colony counts for ascospore suspensions after pressure treatment and the appearance of germination vesicles and tubes. Pressures of > 400 MPa additionally sensitized the ascospores to subsequent heat treatment. At pressures of > 500 MPa, activation occurred in a few minutes but was followed by inactivation with longer exposure. However, even with the most extreme pressure treatment, a fraction of the ascospore population appeared to resist both activation and inactivation, and the maximal achievable reduction of ascospores was on the order of 3.0 log10 units. Pressure-induced ascospore activation at 400 MPa was temperature dependent, with minimum activation at 30 to 50 degrees C and > or = 10-fold higher activation levels at 10 to 20 degrees C and at 60 degrees C, but it was not particularly pH dependent over a pH range of 3.0 to 6.0. Pressure inactivation at 600 MPa, in contrast, was pH dependent, with the inactivation level being 10-fold higher at pH 6.0 than at pH 3.0. Observation of pressure-treated and subsequently dried spores with the use of light and scanning electron microscopy revealed a collapse of the spore structure, indicating a loss of the spore wall barrier properties. Finally, pressure treatment sensitized T. macrosporus ascospores to cell wall lytic enzymes.
研究了高静水压处理（压力高达700兆帕）对大孢篮状菌子囊孢子的影响。在20摄氏度时，≥200兆帕的压力可诱导休眠子囊孢子的活化和萌发，压力处理后子囊孢子悬液的菌落计数增加以及萌发泡和芽管的出现表明了这一点。>400兆帕的压力还使子囊孢子对随后的热处理更敏感。在>500兆帕的压力下，几分钟内就会发生活化，但长时间暴露后会随之失活。然而，即使进行最极端的压力处理，仍有一部分子囊孢子群体似乎能抵抗活化和失活，子囊孢子的最大可实现减少量约为3.0个对数10单位。400兆帕压力诱导的子囊孢子活化与温度有关，在30至50摄氏度时活化最小，在10至20摄氏度和60摄氏度时活化水平高≥10倍，但在3.0至6.0的pH范围内对pH的依赖性不强。相比之下，600兆帕的压力失活与pH有关，在pH 6.0时的失活水平比在pH 3.0时高10倍。使用光学显微镜和扫描电子显微镜观察压力处理并随后干燥的孢子，发现孢子结构塌陷，表明孢子壁屏障特性丧失。最后，压力处理使大孢篮状菌子囊孢子对细胞壁裂解酶更敏感。
