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International audience; Despite the in vitro efficacy of various essential oils (EOs), their practical use to control toxigenic Fusarium spp is limited by their high volatility and sensitivity to UV and oxidation. Their nano-encapsulation can provide protection for the active volatile molecules and allow for a gradual release into the environment. Mesoporous silica nanoparticles (MSNPs) are inert, mechanically stable, stable in suspension in an aqueous medium and their specific surface area is very suitable for functionalization. We have used them for the encapsulation of EOs with antifungal and antimycotoxin activity Mesoporous silica nanoparticles synthesis tetraethyl orthosilicate (TEOS)

International audience; Enniatins are emerging mycotoxins produced by Fusarium species. They are frequently found as contaminants in cereal grains in recent years. The synthesis of these secondary metabolites is often a response to biotic and abiotic stresses. Therefore, the introduction of fungicides into the environment of toxigenic fungi can lead to an increase in mycotoxin accumulation. The search for molecules with both antifungal and antimycotoxigenic activities is a challenge to preserve food safety. Essential oils (EOs) have a promising potential as natural fungicides and should be used both to control fungi and/or their mycotoxin production. In the present work, we extracted the essential oil of Tunisian Thymus capitatus and tested its effect in vitro on two enniatin-producing Fusarium strains when placed in contact with the mycelium in solid medium or used as a fumigant. In agar medium, contact tests measured with two different sets of EOs for a strain of Fusarium avenaceum provided an IC 5O of 0.05 µL EO mL-1. For another strain of Fusarium sp. it was found an IC 50 of 0.08 µL EO mL-1. Fungistatic activity induced no overproduction of enniatins and in contrast, decreases of 55% were found in some samples. Volatile components diffusing in a sealed container also had fungistatic activity that was both dose (5 to 25 µL 1.5 L-1) and time (6 to 24 days) dependent. No fungal acclimation to the EOs and no persistent effect of the EOs were observed, but the decrease in protective effect with increasing incubation time was probably due to EOs alterations.