Van Boeijen Ineke K H, Moezelaar Roy, Abee Tjakko, Zwietering Marcel H
Top Institute for Food and Nutrition, P.O. Box 557, 6700 AN Wageningen, The Netherlands.
J Food Prot. 2008 Oct;71(10):2007-13. doi: 10.4315/0362-028x-71.10.2007.
High hydrostatic pressure (HHP) inactivation of three Listeria monocytogenes strains (EGDe, LO28, and Scott A) subjected to 350 MPa at 20 degrees C in ACES buffer resulted in survival curves with significant tailing for all three strains. A biphasic linear model could be fitted to the inactivation data, indicating the presence of an HHP-sensitive and an HHP-resistant fraction, which both showed inactivation according to first-order kinetics. Inactivation parameters of these subpopulations of the three strains were quantified in detail. EGDe showed the highest D-values for the sensitive and resistant fraction, whereas LO28 and Scott A showed lower HHP resistance for both fractions. Survivors isolated from the tail of LO28 and EGDe were analyzed, and it was revealed that the higher resistance of LO28 was a stable feature for 24% (24 of 102) of the resistant fraction. These HHP-resistant variants were 10 to 600,000 times more resistant than wild type when exposed to 350 MPa at 20 degrees C for 20 min. Contrary to these results, no stable HHP-resistant isolates were found for EGDe (0 of 102). The possible effect of HHP survival capacity of stress-resistant genotypic and phenotypic variants of L. monocytogenes on the safety of HHP-processed foods is discussed.
在ACES缓冲液中于20℃下对三株单核细胞增生李斯特菌（EGDe、LO28和Scott A）施加350 MPa的高静水压（HHP）灭活，结果显示这三株菌的存活曲线均有明显拖尾现象。双相线性模型可拟合灭活数据，表明存在一个HHP敏感部分和一个HHP抗性部分，二者均呈现一级动力学的灭活情况。详细定量了这三株菌这些亚群的灭活参数。EGDe的敏感和抗性部分显示出最高的D值，而LO28和Scott A的两个部分对HHP的抗性较低。对从LO28和EGDe拖尾部分分离出的存活菌进行分析，结果表明，LO28较高的抗性是24%（102株中的24株）抗性部分的一个稳定特征。当在20℃下暴露于350 MPa 20分钟时，这些HHP抗性变体的抗性比野生型高10至600,000倍。与这些结果相反，未在EGDe中发现稳定的HHP抗性分离株（102株中0株）。讨论了单核细胞增生李斯特菌抗逆基因型和表型变体的HHP存活能力对HHP处理食品安全性的可能影响。
