肠毒素和生物被膜是金黄色葡萄球菌（金葡菌）最重要的食品安全危害因素，导致食物中毒和食品污染。群体感应在金葡菌毒素和生物被膜形成过程中起重要作用，但目前对食源性金葡菌群体感应信号分子的产生及其与肠毒素和生物被膜形成之间的关系并不清楚。本项目以生物被膜形成能力强和/或肠毒素产生能力强的食源性金葡菌为研究对象，通过对不同环境（温度、碳源和NaCl）下食源性金葡菌群体感应信号分子（AIPs和AI-2）的产生及其对肠毒素和生物被膜形成的影响进行研究，阐明群体感应机制在不同环境下食源性金葡菌肠毒素和生物被膜形成中的作用；通过构建Agr和LuxS基因敲除菌株以及在敲除菌株中添加外源群体感应信号分子（AIPs和AI-2），进一步确证群体感应对不同环境下食源性金葡菌肠毒素和生物被膜形成中的作用，为建立以干扰食源性金葡菌群体感应为靶点的新型食品安全控制技术体系提供理论依据。

Enterotoxins and biofilms are the most important food risk factors posed by Staphylococus aureus, which cause food poisoning and food contamination. Quorum sensing plays an important role in the enterotoxin production and biofilm formation. But the relationship between production of quorum sensing molecules and the formation of enterotoxin and biofilm are still not fully explored. This proposal will use the selected stain which are good at forming biofilm or producing enterotoxin, to study the production of quorum sensing molecules under different conditions (temperature, carbon source and sodium chloride), and their role in the enterotoxin production and biofilm formation. Through constructing Agr and LuxS knock-out strain and adding external quorum sensing molecules, the role of quorum sensing in enterotoxin production and biofilm formation will be confirmed. The findings from this project will provide theoretical basis to construct a food safety control system which will target quorum sensing in Staphylococcus aureus.