Boziaris I S, Humpheson L, Adams M R
School of Biological Sciences, University of Surrey, Guildford, UK.
Int J Food Microbiol. 1998 Aug 18;43(1-2):7-13. doi: 10.1016/s0168-1605(98)00083-x.
The ability of heat injury to confer sensitivity to nisin in a Gram negative pathogen was investigated. Injury and inactivation kinetics of Salmonella enteritidis PT4 in the presence of nisin were determined in media, liquid whole egg and egg white using cultural methods and capacitance monitoring to detect injury. Addition of nisin in concentrations from 500 IU/ml to 2500 IU/ml in the heating menstruum caused a reduction of required pasteurisation time of up to 35%, principally as a result of its effect on cells suffering damage during heating. In egg white and liquid whole egg the organism's heat susceptibility was greater than in nutrient broth, particularly in egg white which contained no fat and had an alkaline pH. The effect of nisin on heat susceptibility was however less pronounced than in nutrient broth due to its interaction with protein and fat. Though nisin did not enhance the lethality of heat processes, injury is more severe in egg white containing nisin, presumably as a result of its interaction with antimicrobial factors in egg white.
研究了热损伤赋予革兰氏阴性病原菌对乳链菌肽敏感性的能力。采用培养方法和电容监测来检测损伤，测定了在乳链菌肽存在下肠炎沙门氏菌PT4在培养基、全蛋液和蛋清中的损伤及失活动力学。在加热介质中添加浓度为500 IU/ml至2500 IU/ml的乳链菌肽可使所需的巴氏杀菌时间减少高达35%，这主要是由于其对加热过程中受损细胞的作用。在蛋清和全蛋液中，该微生物对热的敏感性高于在营养肉汤中，尤其是在不含脂肪且pH呈碱性的蛋清中。然而，由于乳链菌肽与蛋白质和脂肪的相互作用，其对热敏感性的影响在蛋清和全蛋液中不如在营养肉汤中明显。虽然乳链菌肽不会增强热杀菌过程的致死性，但在含有乳链菌肽的蛋清中损伤更为严重，这可能是由于其与蛋清中的抗菌因子相互作用的结果。
