肠炎沙门氏菌标准物质冻干保护剂的设计

The Design of Protective Agents of Reference Materials Preparation of Salmonella enteritidis

以肠炎沙门氏菌为选制菌种,以无菌鸡肉糜作为活菌标准物质基质,采用冷冻真空干燥法研制活菌标准物质,共研制6个批次,制备活菌标准物质240份。利用正交法试验对保护剂进行选择及优化,结果表明:脱脂奶、蔗糖、聚乙烯吡咯烷酮以及L-谷氨酸钠,分别按照20%、10%、8%以及3%的添加量与无菌去离子水混合,细菌在冻干后存活率达38%;与鸡肉基质按比例混合,冻干后,细菌存活率为46%。冻干标准物质均匀性试验结果显示:相对重复性标准差为2.185%,相对再现性标准差为2.185%,方差分析P值均大于0.05,表明批次内以及批次间无显著差异。稳定性试验表明:在-20℃条件下,活菌标准物质稳定性良好。制备的肠炎沙门氏菌活菌标准物质具有相应的菌种特性,良好的稳定性,说明优化的保护剂配方适合用于该标准物质的冻干。

Salmonella enteritidis was Choosed as the target species and the chicken mince mixed protectant formula served as matrix in Living Bacterium Reference Material. The Lyophilization method was adopted to develop Live Bacterium Reference Material Six batches were run and 240 bottles of Raw Chicken Matrix obtained. The orthogonal design was used to select and optimize the protective agents. The results showed that in protective agent formulation that the percentage of skim milk, sucrose, polyvinylpyrrolidone, and monosodium-L were 20%, 10%, 8% and 3%respectively, after freeze-drying, the survival of bacteria was 38%. The results of the uniformity experiment showed that, the repeatability standard deviation of raw chicken matrix was 2.185%and the reproducibility standard deviation, 2.185%. The results of the Analysis of Variance were P〉0.05. It indicated that there was no significant difference between the six batches of RM. Stability experiments showed that stored at-20℃, the RM had good stability. The Salmonella Enteritidis Live Bacterium Reference Material bears the corresponding strain properties, and good stability. Optimized protective formula is suitable for the freeze-drying of Reference Materials.