温度和盐含量对三文鱼中单增李斯特菌热失活的影响

Effect of Temperature and Salt on Thermal Inactivation of Listeria monocytogenes in Salmon

主要考察菌株、温度、盐含量对三文鱼中单增李斯特菌热失活动力学的影响。菌株编号为CICC 21632、CICC 21633、CICC 21635、CICC 21639的4株单增李斯特菌分别接种至盐含量为0, 1.5%, 3.0%和4.5%的三文鱼中,并于不同温度(57.5℃～67.5℃)条件下测定D值。结果表明,单增李斯特菌的热抗性(log D)受菌株、温度、盐含量,以及因素间交互作用的影响显著;菌株CICC 21632为4株受试菌株中热抗性最高, Z值为6.02℃,其热抗性随着盐含量增加而线性增加。动力学分析结果和建立的模型可用于水产品加工行业设计合适的热处理规程,以消除三文鱼中的单增李斯特菌,并确保其微生物性安全。

The effects of bacterial strain, temperature, and salt concentration on thermal inactivation kinetics of Listeria monocytogenes in salmon were studied. Four different strains of L. monocytogenes, including CICC 21632, CICC 21633, CICC 21635, CICC 21639, were individually inoculated to salmon supplemented with salt(0, 1.5%, 3.0% and 4.5%), and heated under different temperatures(57.5 ℃-67.5 ℃) to evaluate the survival of the bacterium during heating and determine the D-values. The results showed that the thermal resistance(log D) of L. monocytogenes was significantly affected by bacterial strain, temperature, and salt and by their interactive effects, with strain CICC 21632 being the most heat-resistant among all four strains tested. Salt added to salmon roe significantly increased the thermal resistance of the bacteria. For L.monocytogenes CICC 21632, the Z value of the bacterium in salmon was 6.02 ℃, and its heat resistance increased with the level of salt in a linear manner. The results of kinetic analysis and the models obtained could be used by the seafood industry to develop proper thermal processes to eliminate L. monocytogenes in salmon and to ensure microbial safety.