The consumption of mycotoxin-contaminated commodities is related to several acute and chronic diseases in humans. Consumer pressure in Europe has resulted in efforts to find effective natural compounds to substitute existing food grade preservatives to control the growth of mycotoxigenic food spoilage moulds. In this project the research of the functional relationship between natural anti-fungals, direct impact on the key mycotoxin clusters genes as well as relating this to phenotypic mycotoxin production will facilitate the understanding of their differential mechanisms of action. A limited number of antifungal natural compounds have shown good efficacy against mycotoxigenic spoilage moulds (Penicillium, Aspergillus and Fusarium). However, inhibition of mycotoxin production is affected by environmental conditions and in some cases low levels of these compounds have been found to stimulate mycotoxins production (ochratoxin, deoxynivalenol, fumonisins). This study will use multidisciplinary tools at a molecular, cellular, fungal morphology and colony structure level, to understand the differential way of action of fungistatics and fungicides against key mycotoxigenic species under different environmental regimes. Techniques as LC-MS, RT-PCR, fluorescence staining and analysis by confocal microscopy and flow cytometry, will be applied. The results generated will provide a method for better understanding the mechanisms of action as well as providing guidelines for the best GRAS chemicals to use under different environmental condition to prevent contamination by such natural toxins.