冷熏三文鱼单增李斯特菌热灭菌规律及其品质变化动力学研究

Thermal Sterilization of Listeria Monocytogenes and Kinetics of Quality Changes in Cold Smoked Salmon

摘要:

为了给冷熏三文鱼热灭菌提供理论依据，试验研究了热处理对冷熏三文鱼中单增李斯特菌失活及品质变化影响。将接种了一株单增李斯特菌（ATCC19113）菌液的鱼肉密封于毛细管中，分别在58 ℃、60 ℃、62 ℃、64 ℃和66 ℃条件下加热处理18 min、8.8 min、4 min、2 min和1 min，考察不同温度条件下存活菌数变化。采用铝制密封加热单元（直径35 mm×高6 mm）研究了冷熏三文鱼（直径30 mm×高6 mm）在50 ℃、57 ℃、64 ℃和70 ℃条件下加热处理120 min、90 min、60 min和40 min时的品质变化。结果表明：单增李斯特菌的热失活曲线遵循对数线性关系（R2≥0.94）；冷熏三文鱼品质指标加热失重率、a*值、b*值及剪切力遵循1级反应动力学规律，L*值遵循0级反应动力学规律；冷熏三文鱼色值a*与单增李斯特菌热失活密切相关，色值a*品质劣变曲线与单增李斯特菌（ATCC19113）死亡曲线重叠区域为热处理温度与时间组合可操作范围，此范围可同时满足杀菌及品质保持要求。

Abstract:

In order to provide a theoretical foundation for the thermal sterilization of cold smoked salmon, the influence of heat treatments on the inactivation of Listeria monocytogenes and the changes in the quality of cold smoked salmon were investigated. A sample of cold smoked salmon inoculated with a strain of L. monocytogenes (ATCC19113) was sealed in a capillary tube, and subjected to heat treatment at 58 ℃, 60 ℃, 62 ℃, 64 ℃, and 66 ℃ for 18 min, 8.8 min, 4 min, 2 min, and 1 min, respectively. The changes in viable bacterial cell count at the different temperatures was monitored. Small samples (D 30 mm × H 6 mm) were sealed in an aluminium heating unit (D 35 mm × H 6 mm) and heated in a water bath at 50 ℃, 57 ℃, 64 ℃, and 70 ℃ for 120 min, 90 min, 60 min, and 40 min, respectively. The corresponding changes in quality were studied. The results showed that the inactivation curve exhibited a logarithmic linear relationship (R2 ≥ 0.94). The quality indexes of cold smoked salmon, including cooking loss, the a* value, b* value, and the shear force followed first-order reaction kinetics, while the L* value followed zero-order reaction kinetics. As the a* value of cold smoked salmon was closely linked to thermal inactivation of L. monocytogenes, the overlapping region between thermal-death-time curves of L. monocytogenes (ATCC19113) and the a* quality deterioration curve was the operational range to carry out the combination of temperature and heat treatment time, which could meet the requirements for sterilization without deteriorating quality of cold smoked salmon.