中文摘要：

热杀索丝菌对猪肉的致腐作用主要来自于其分泌的酶对猪肉蛋白质及碳水化合物的分解。前期研究发现，在STAA液体培养基中，热杀索丝菌分泌蛋白酶少，其胞外蛋白酶酶活难以准确检测出。在国标福林酚法的基础上，以10、20、30、40、50、60min作为反应时间，测定热杀索丝菌于猪肉蛋白提取液中培养过程中所分泌的胞外蛋白酶酶活。结果表明：在热杀索丝菌初始数量远大于其他菌数目总和的条件下，热杀索丝菌增殖不如其他菌迅速，24h时，其他菌数目已大于热杀索丝菌数目。此外，培养过程中，36h以后，所测胞外蛋白酶酶活增大十分显著（P〈0．01）。未严格除菌的条件下，猪肉水溶性蛋白提取液中的胞外蛋白酶主要由热杀索丝菌以外的微生物分泌。

英文摘要：

The putrefaction of pork caused by Brochothrix thermosphacta mainly lies in the decomposition of protein and carbohydrates in pork by the enzyme secreted by Brochothrix thermosphacta. Previous studies have found that in STAA liquid medium, the proteases secreted by Brochothrix thermosphacta was few that the activity was difficult to be detected accurately. In this paper, on the basis of the national standard the Forint phenol method, with 10, 20, 30, 40, 50, 60 min as reaction time respectively, the activity of extracellular proteases produced in culturing in the water-soluble protein extract of pork by Brochothrix thermosphacta was detected. It was showed that the Brochothrix thermosphacta showed low fertility under the condition of the number of the Brochothrix thermosphacta was much higher than the sum of the other microbes. As a consequence, the sum of the other bacterium is greater than the Brochothrix thermosphacta. Moreover, after 36 h, the extracellular proteases activity increased significantly. It turns out that, the extracellular proteases were mainly secreted by the bacterium beyond Brochothrix thermosphacta.