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 B-2 and fumonisin B-4 on grapes in the range 171-7841 mu g fumonisin B-2/kg and 14-1157 mu g fumonisin B-4/kg. Four selected strains were able to produce fumonisin B-2 (5-6476 mu g/kg) and fumonisin B-4 (12-672 mu g/kg) on raisins.