阪崎肠杆菌标准品制备中冻干工艺的优化

本研究对阪崎肠杆菌(Enterobacter sakazakii)冻干工艺进行优化,旨在为E.sakazaki定性标准品和定量标准品的制备提供技术基础,同时为其他肠杆菌科标准品的制备工艺提供理论指导.实验结果表明:最佳冻干保护剂组合为海藻糖3%,脱脂奶粉8%,谷氨酸钠1.5%;最佳预冻温度和预冻时间分别为-20℃,4 ...

Optimization of freeze-drying process for E.sakazakii standard material

The freeze-drying process of Enterobacter sakazakii was optimized to provide a technical basis for the preparation of E. sakazakii qualitative and quantitative standard material, as well as a theoretical guide for the preparation of other Enterobacteriaceae standard material. The results showed that the best freeze-dried protectants were as follows： trehalose 3 %, skim milk powder 8 % and sodium glutamate 1.5 % ; the best pre-freezing temperature was -20℃, and the best pre-freezing time was 4 hours. Under these conditions the survival of E. sakazakii was up to 70.4 %. The water activity （Aw） of E. sakazakii powder decreases significantly at the beginning of freeze-drying, but it would not be much lower than that after 10 hours. When the freeze-drying time was 7 hours, E. sakazakii powder with Aw 0. 179 was obtained, which was the most stable for various artificialtransportation temperatures.