The viability of freeze-dried cells of Streptococcus thermophilus and Lactobacillus plantarum by adding different stabilizer and protectants such as skim milk, sucrose and trehalose were investigated. When the bacteria were dried with 150mmol/L trehalose,75% of S. thermophilus and 33% of L. plantarum cells were survived, comparing with control of 19% and 1% respectively. When S. thermophilus was exposed at 90℃, the cells with trehalose increased tolerance to high temperature. When S. thermophilus freeze-thawing for 4 and 8 cycles, the survival was much higher than that of without trehalose protected. Scanning Electro-microscope pictures showed that the cells with trehalose, appeared as normal, but those without the sugar were broken or collapsed. The data confirmed that the disaccharide could protect bacteria against stress conditions.%研究了在冷冻干燥、高温及冻融等胁迫条件下，海藻糖对嗜热链球菌(Streptococcus ther-mophillus)和植物乳杆菌(Lactobacillus plantarum)菌体细胞的保护作用。结果表明在冷冻干燥过程中，海藻糖保护的细胞存活率分别达75％和33％，而对照分别为19％和1％；用90℃高温处理干燥状态和溶液状态的嗜热链球菌,证明海藻糖能明显提高细胞的耐热性；用冻融法反复处理嗜热链球菌4次和8次，加海藻糖保护的细胞存活率显著高于对照。在扫描电镜下观察这些冻融细胞，加海藻糖保护的菌体细胞饱满、完整，对照则有明显的破裂、塌缩，细胞间有丝状物粘连，该结果从细胞亚显微表面结构的变化揭示了海藻糖对细菌细胞的抗逆保护作用。
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