大肠埃希菌和金黄色葡萄球菌的最低生长水分活度测定

Determination of the minimum water activity for growth of Escherichia coli and Staphylococcus aureus

中文关键词:  水分活度  大肠埃希菌  金黄色葡萄球菌  生长曲线

英文关键词:water activity  Escherichia coli  Staphylococcus aureus  growth curve

中文摘要:

      目的 探索大肠埃希菌和金黄色葡萄球菌的最低生长水分活度(water activity, Aw)。方法 分别采用定性和定量试验, 研究在NaCl、蔗糖、甘油3种水分活度调节剂作用下, 水分活度对大肠埃希菌和金黄色葡萄球菌生长规律的影响。结果 大肠埃希菌的最低生长水分活度为0.922~0.950, 金黄色葡萄球菌的最低生长水分活度为0.864~0.900。根据对生长曲线的分析, 随着水分活度下降, 大肠埃希菌和金黄色葡萄球菌的总生长量降低, 停滞时间延长, 比生长速率下降。结论 水分活度调节剂会影响细菌的最低生长水分活度, 大肠埃希菌对甘油更为耐受, 而金黄色葡萄球菌对氯化钠更为耐受。2种菌的比生长速率呈线性下降规律, 且在氯化钠和蔗糖的比生长速率下降规律基本一致。

英文摘要:

      Objective To explore the minimum growth water activity (Aw) of Escherichia coli and Staphylococcus aureus. Methods The effect of Aw on the growth of E. coli and S. aureus under the action of NaCl, sucrose and glycerin was studied by qualitative and quantitative tests. Results The minimum Aw for growth of E. coliwas 0.922-0.950, and that of Staphylococcus aureus was 0.864-0.900. With the decrease of water activity, the total growth of E. coli and S. aureus decreased, the stagnation time prolonged, and the specific growth rate decreased, according to the analysis of growth curve. Conclusions Water activity regulator can affect the minimum levels of Aw for growth of microorganisms. E. coli is more tolerant to glycerol, while S. aureusis NaCl. The specific growth rate of the 2 microorganisms show a linear decline rule, and the decline rule is basically the same for the specific growth rate of NaCl and sucrose.