Kalchayanand N, Sikes A, Dunne C P, Ray B
Animal Science Department, University of Wyoming, Laramie, 82071, USA.
J Food Prot. 1998 Apr;61(4):425-31. doi: 10.4315/0362-028x-61.4.425.
High hydrostatic pressure, because it can kill microorganisms, is being investigated for potential use as a nonthermal food preservation method. The objective of this study was to determine the hydrostatic pressurization parameters, pressure, time, and temperature, and a bacteriocin that in combination would destroy 7 to 8 log cycles of pathogenic and spoilage bacterial populations. We suspended cells of Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium, Escherichia coli O157:H7, Lactobacillus sake, Leuconostoc mesenteroides, Serratia liquefaciens, and Pseudomonas fluorescens in peptone solution and exposed them to the combination of treatments. The combined parameters used were hydrostatic pressure (138 to 345 MPa), time (5 to 15 min), temperature (25 to 50 degrees C), and pediocin AcH (3,000 AU/ml, final concentration). In general, cell death increased as the pressure, time, or temperature increased; however, the cells developed proportionately greater sensitivity as the pressure increased to 276 MPa and higher and the temperature increased above 35 degrees C. Pressurization for longer than 5 min, especially at lower pressure and temperature ranges, had very little added benefit. Among the four gram-negative species, E. coli O157:H7 was the most resistant to pressurization while among the four gram-positive species, L. sake and L. mesenteroides had greater resistance. The death rate at high pressure (345 MPa) and high temperature (50 degrees C) in combination followed first-order kinetics; at lower pressure and temperature combination it showed a late tailing effect. Estimated D value data indicated that even at 345 MPa and 50 degrees C an 8-log-cycle viability loss could not be achieved within 5 min for all eight species. However, when pediocin AcH was included during pressurization this loss was achieved.
由于高静水压能够杀灭微生物，因此人们正在研究将其用作一种非热食品保鲜方法的潜力。本研究的目的是确定静水压参数（压力、时间和温度）以及一种细菌素，它们联合使用时能够消灭7至8个对数周期的致病和腐败细菌群体。我们将金黄色葡萄球菌、单核细胞增生李斯特菌、鼠伤寒沙门氏菌、大肠杆菌O157:H7、清酒乳杆菌、肠系膜明串珠菌、液化沙雷氏菌和荧光假单胞菌的细胞悬浮在蛋白胨溶液中，并使其接受联合处理。所使用的联合参数包括静水压（138至345兆帕）、时间（5至15分钟）、温度（25至50摄氏度）和植物乳杆菌素AcH（最终浓度为3000 AU/ml）。一般来说，细胞死亡率随着压力、时间或温度的升高而增加；然而，随着压力升至276兆帕及更高以及温度升至35摄氏度以上，细胞相应地变得更加敏感。加压超过5分钟，尤其是在较低的压力和温度范围内，几乎没有额外的益处。在四种革兰氏阴性菌中，大肠杆菌O157:H7对加压最具抗性，而在四种革兰氏阳性菌中，清酒乳杆菌和肠系膜明串珠菌具有更强的抗性。高压（345兆帕）和高温（50摄氏度）联合作用下的死亡率遵循一级动力学；在较低的压力和温度组合下，它表现出后期拖尾效应。估计的D值数据表明，即使在345兆帕和50摄氏度下，5分钟内也无法使所有八个菌种的存活率损失达到8个对数周期。然而，在加压过程中加入植物乳杆菌素AcH时，就能实现这种存活率损失。
