食品加工贮藏过程中，各种胁迫条件诱导残存的食源性致病菌产生应激耐受，增强菌株毒性，因而产生更高的食品安全风险。与具有较强抗酸能力的致病性大肠埃希氏菌 O157:H7相比，非O157（non-O157）尤其是“Big six”对公众健康存在更大威胁，non-O157菌株亦具有一定抗酸性，可在酸性食品中生长存活。然而酸应激下non-O157的酸耐受反应及它的毒性受到何种影响尚不清楚。因此，本项目以“Big six” non-O157有毒菌株为研究对象，以动物源酸性食品——发酵香肠为载体，研究non-O157抗酸有毒菌株与非抗酸有毒菌株在酸应激下生理特性及毒力特性的变化，进而重点采用转录组学和蛋白质组学方法分析差异表达基因和蛋白，探讨non-O157菌株耐酸与毒力内在关联机制。本研究可为non-O157食品风险评估提供理论依据，为实际生产加工中non-O157综合防腐措施的有效实施提供科学思路。

During food processing and storage, foodborne pathogens are induced stress tolerance and virulence enhancement under various stress conditions, which will bring more serious food safety risk. Compared with the acid-resistant pathogenic Escherichia coli O157:H7, non-O157, especially “Big six” strains, poses more serious threats to public health. Non-O157 strains can grow and survive in acid food due to their acid resistance. However, the effects of acid stress on the acid tolerance and virulence of non-O157 are not clear. In view of the above concern, we attempt to investigate the acid stress response of pathogenic non-O157 in fermented sausage, to investigate the changes of physiological characteristics and virulence of acid-resistant and non-acid resistant non-O157 under acid stress, and then analysis of differentially expressed genes and proteins by means of transcriptomics and preteomics are employed to reveal the mechanisms of inner connection between acid tolerance and virulence of non-O157. The research will provide a theoretical base for risk assessment of non-O157 in food and a scientific guide for comprehensive control of non-O157 in the practical food processing.