低水活度控制作为最经济而有效的食品保藏方法被广泛应用，然而近年不断出现的沙门氏菌污染低水活度食品并引发疾病甚至死亡的事件向人类敲响了警钟。前期研究提示，低水胁迫可能诱导沙门氏菌进入VBNC状态，交叉抗性产生以及毒力改变。这些特征对以配方乳粉为代表的低水活度食品安全评估以及致病菌污染控制极为不利。本项目研究低水胁迫沙门氏菌进入VBNC状态，对热、抗生素、消毒剂、紫外和模拟胃肠胁迫环境产生的交叉抗性，以及毒力变化等生理表现型同时，又通过构建缺陷型菌株，采用转录组学分析、蛋白质和基因定量表达分析以及生物信息学技术深入解析低水胁迫下sRNA调控转录调节因子RpoS表达，RpoS参与菌体进入VBNC状态诱导因子、环境适应性因子、以及毒力因子相关基因转录的分子机制。研究结果不仅可丰富逆境胁迫致病菌生理特征和形成相关机制的科学认知，也为有效控制低水活度食品致病菌残留技术开发提供理论基础。

The Method of keeping low water activity is traditional and effective. It has been used to preserve food widely. In recent years, many of the reported food-borne outbreaks associated with low-moisture foods, which involve Salmonella contamination and leading to hospitalizations and deaths are raising common concerns. Previous research work showed Salmonella exposing to low-aw environments can be induced into VBNC state and enhanced a degree of cross-protection to other common stresses and virulence level. These characterizations are disadvantageous for evaluation of safety and reducing pathogens contamination of low aw foods including milk powder. We will undertake a study to illuminate the characterizations of state of VBNC, cross-protection to heat, disinfectant, ultraviolet, simulated gastrointestinal and small intestinal system and virulence. On the other side, This study will reveal the mechanism the sRNAs play important role on RpoS expression, which regulate expressions of the genes transnscription of VBNC inducible factor, environmental adaptability factors and violence factors by the methods of RNA-Seq, real time PCR and protein analysis and bioinformatics in mutations. Our finding would be of great importance not only for enriching the knowledge about physiological characteristics and mechanisms of pathogens under stresses, but also for providing an effective technical strategy to eliminate desiccation-adapted human pathogens from low water activity foods.