黄曲霉毒素M1（AFM1）是牛奶中唯一有安全限量的霉菌毒素。但是，近年监测发现牛奶中AFM1与其他霉菌毒素交互存在的现象较为普遍，而这种交互存在对人类健康危害、作用机理及限量研究在国内外尚无报道。本团队研究发现，AFM1与赭曲霉毒素A（OTA）和玉米赤霉烯酮（ZEA）交互存在时对人类肠道上皮细胞模型Caco-2细胞致死率存在协同作用。为此，本项目提出假设：多种霉菌毒素交互存在与单一霉菌毒素的危害不同。本研究用Caco-2细胞系与HT29-MTX细胞系联合培养，构建肠道上皮细胞系模型，从单细胞结构、细胞层完整性和细胞分泌功能三个层次，研究比较AFM1、OTA、ZEA单独及交互作用对细胞结构损伤、细胞层紧密连接蛋白损害和杯状细胞粘蛋白分泌的影响，系统解析肠道上皮屏障损伤机制。研究结果将为开展奶产品中霉菌毒素交互作用的危害评估提供新方法，为准确制定不同霉菌毒素及其交互作用的安全限量提供科学依据。

Aflatoxin M1 (AFM1) is the only mycotoxin in milk with legal limits. Recently, co-occurrence of multiple mycotoxins in milk was found to be widely existence. However, no report on the adverse effects, mechanisms and legal limits for the co-occurrence of multiple mycotoxins. Our previous study showed that AFM1 in co-presence of ochratoxin A (OTA) and zearalenone (ZEA) demonstrated synergistic cytotoxicity on Caco-2 intestinal epithelial cells. Here we proposed a research hypothesis that cytotoxicity is different in the case of co-occurrence of multiple mycotoxins compared with that of individual mycotoxin. We will establish the co-cultured intestinal epithelial cell line of Caco-2 and HT29-MTX as an intestinal epithelial cell model to explore the mechanism of monolayer damage of intestinal epithelial cells based on single cell, monolayer cells and cell secretion function. The experiments will be carried out on the effects of AFM1, OTA and ZEA individual and interaction on the cellular ultrastructure, tight junction protein in monolayer cells and mucin secretion. This study will develop a novel method for risk assessment of mycotoxins in dairy products, and provide important scientific evidence for the development of the safety exposure limits of mycotoxins in food, especially in dairy products.