Abstract
Mycotoxins are toxic secondary metabolites secreted by filamentous fungi, mainly belonging to the genera Aspergillus, Fusarium and Penicillium, in food productions of plant origin. Contamination by mycotoxins causes significant economic losses. These molecules are also resistant to processing treatments such as cooking or roasting and can therefore be found in the entire food chain. About thirty of them are recognized for their harmful effects on human and animal health. The use of fungicides is currently the most used means to fight against the mycotoxic risk. However, in a context of sustainable development, alternatives based on biocontrol are to be developed. The objective of this work was to study a biological control method that could reduce the contamination by mycotoxins considered to be of concern and produced by certain fungal strains, Aspergillus flavus, Aspergillus carbonarius and Fusarium verticillioides, which produce aflatoxin B1, ochratoxin A and fumonisin B1 respectively. Plant extracts have long been known as antifungal agents and the first strategy was to use a commercial biological control product, Antoferine®, which is a natural vine extract containing polyphenols, produced by the company Antofenol (Plestan, France). This product has already been tested for its antifungal activity but this is the first study devoted to its impact on mycotoxins. The second strategy was to test three essential oils extracted from Cymbopogon schoenanthus, Cymbopogon nardus and Eucalyptus camaldulensis. Antoferine® showed a dose-dependent activity on fungal growth and toxin production, and to a lesser extent on spore production, of A. flavus and F. verticillioides. Its effect on the growth of A. carbonarius was more contrasted since growth was only slightly impacted and toxin production was stimulated. Antoferine® also showed a potential detoxification of aflatoxin B1 produced by A. flavus. Concerning the three essential oils, inhibitory effects were demonstrated on the growth and mycotoxin production of A. flavus, A. carbonarius and F. verticillioides using a direct contact method and a disk diffusion method. In general, the essential oils of Cymbopogon schoenanthus and Cymbopogon nardus showed higher activity than Eucalyptus camaldulensis essential oil but it is interesting to note that E. camaldulensis was able to inhibit mycotoxin production with no or lesser effect on fungal growth.