Production of fumonisin B₂ and B₄ by aspergillus niger on grapes and raisins

The recent discovery of fumonisin production in Aspergillus niger, raises concerns about the presence of these mycotoxins in grapes and raisins as well as other commodities where A. niger is a frequent contaminant. Here we investigate the potential production of fumonisins in A. niger cultured on grapes and raisins. Sixty-six A. niger, 4 A. tubingensis, and 16 A acidus strains isolated from raisins were tested for fumonisin production on laboratory media. Neither A. tubingensis nor A. acidus strains produced fumonisins, but 77% of A. niger strains did. None of the strains produced ochratoxin A. Ten selected fumonisin producing A. niger strains were further able to produce fumonisin B₂ and fumonisin B₄ on grapes in the range 171-7841 μg fumonisin B₂/kg and 14-1157 μ.g fumonisin B₄/kg. Four selected strains were able to produce fumonisin B₂ (5-6476 μg/kg) and fumonisin B₄ (12-672 μg/kg) on raisins.