高温胁迫对德尔卑沙门氏菌抗逆性的影响

Effects of high temperature stress on stressresistance of thermotolerant Salmonella Derby stresses

以德尔卑沙门氏菌(Salmonella Derby,SD)为研究对象,通过高温培养驯化获得高温耐受性SD,研究其在环境胁迫条件下的耐受性。经高温驯化后,55℃处理20min,高温耐受菌株的存活率是对照菌株存活率的1.5倍。在pH 3.0,2.4环境下,高温耐受菌株存活率高于对照组,但处于碱胁迫过程中,高温耐受菌株变得更加敏感,pH 12处理30min,对照组存活率为33.83%,高温耐受菌株完全被杀灭。在乙醇、NaClO环境下,高温耐受菌株相较于对照组更加敏感;但在125mmol/L HO2条件下,高温耐受菌株存活率高于对照组(30.05%)存活率;对-20℃冷冻处理前期,其耐受性明显高于对照组。SD经高温胁迫后提高对酸、H2O2、低温的交叉抗性,同时也增加对碱、乙醇、NaClO等胁迫的敏感性,联合使用有助于提高灭菌效果。

The application of high temperature treatment to food is one of the most common methods for eliminating microbial contamination. In this study, high temperature tolerance of Salmonella Derby(SD)was obtained by high temperature culture and the effect of the heat-stressed SD on its response to environment stresses The survival rate of high temperature domesticated SD was 1.5 time higher in 55 ℃ for 20 min than the control group. The survival rate of high temperature domesticated SD was better in pH 3.0 and pH 2.4 acid challenge. The high temperature tolerant bacteria had enhanced sensitivity to alkali, ethanol and NaClO. The survival of the control group was 33.83%, but the high temperature tolerance SD did not survive in pH 12 for 30 min . On the other hand, The survival rate of thermotolerant SD was 30.05% better than the control group under 125 mmol/L H2O2 stress. The control group was more susceptible to -20 ℃. Temperature stress enhance tolerant SD to acid, H2O2 and -20 ℃ low temperature and sensitivity to alkali, ethanol and NaClO. The combination of environmental stress helps to improve the sterilization effect of thermotolerant SD.