Fumonisins B, A and C profile and masking in Fusarium verticillioides strains on fumonisin-inducing and maize-based media

The production of fumonisin B, A and C and hidden and partially hydrolysed fumonisin occurrence was investigated in 3 strains of Fusarium verticillioides isolated from maize, cultured for 21–45 days on malt extract medium at 25 °C and 0.955–0.990 water activity (aw). Fumonisin A–B and C series were produced by all the strains in all conditions studied, with B-fumonisin ≫ C-fumonisin > A-fumonisin following a similar trend. The dynamic of fumonisin production was significantly influenced by factors considered and their interaction, with aw = 0.990 as favourable condition in ITEM 10026 and ITEM 10027. All fumonisins were maximised at 30 days incubation in ITEM 10027 and ITEM 1744 and at 45 days incubation in ITEM 10026. Partially hydrolysed fumonisins were detected only for the B-group. Hidden fumonisins were never observed in Fusarium cultures grown on malt extract medium but were detected in the additional trial on maize-based medium, suggesting that the masking phenomenon can occur only in a complex matrix.

► Fumonisin B, A and C were produced by all F. verticillioides strains tested.
► Both fumonisins B, A and C production was enhanced at high aw = 0.990.
► No masked fumonisin were recovered on cultures grown on malt extract medium.
► Masked fumonisin were only detected on maize-based cultures.
► Changing in pH was more related to fungal growth than fumonisin production.