Study of volatile organic compounds emitted by mycotoxin-producing fungi in order to develop a sensor.

Mycotoxins are non-volatile secondary metabolites produced by filamentous fungal species belonging to the genera Aspergillus, Fusarium, Penecillium etc. These fungal molecules are highly toxic at low concentrations to all vertebrates including humans. One of the most abundant mycotoxins is aflatoxin B1, which can cause severe illness with chronic exposure and death with acute exposure.
These ubiquitous fungi contaminate foodstuffs (corn, wheat, rice, etc.) at different stages of their cultivation and storage. Methods to prevent their development exist, but none allow for complete eradication of the fungus. Current detection methods consist of analyzing previously extracted samples using ELISA tests or HPLC.

The purpose of the present work is to identify VOC markers characteristic and specific to a mycotoxin-producing fungi contamination.
Using SPME, VOCs emitted by two categories of fungi are identified and semi-quantified: non-aflatoxigenic strains (not producing aflatoxins) and aflotoxigenic strains (producing aflatoxins B1, B2 and G2). In agreement with the literature, some VOCs confirm a fungal contamination linked to a genus Aspergillus (β-chamigrene, ethyl 2-methylpropanoate) and more specifically to the flavus species such as ethyl 2-methylpropanol, ethyl acetate, 3-methylbutanol, ethyl 2-methylbutyrate. In addition, several terpenes are identified (epizonaren, valencene). To highlight some of them as strain-specific, a PLS is applied. The result identified some of the terpenes as potential biomarkers to differentiate between these two categories (β-elemene, γ-gurjunene).

The next step is to correlate specific VOCs and mycotoxin content and compare these data when fungi grow on stored grain to approximate actual conditions. These VOC markers will be molded in a resin and then destroyed by heating to obtain molecularly imprinted polymers for the design of specific sensors.