Use of UV photography to identify aflatoxin-producing strains of Aspergillus flavus and A. parasiticus.

UV photography in glucose, yeast extract (GY) agar medium was tested as a simple and rapid method for the distinction of aflatoxin-positive from aflatoxin-negative strains of Aspergillus flavus and A. parasiticus. In the UV photographs aflatoxin-producing moulds were identified as grey or black colonies, whereas aflatoxin-nonproducing moulds appeared as white colonies. Of the aflatoxin-positive strains detected by the UV photographic method, 10% was confirmed by extraction of the GY agar medium and mould mycelium in chloroform, extracts which were analysed subsequently using thin-layer chromatography. Confirmation of aflatoxigenic strains was achieved by biosynthesis on liquid medium yeast extract sucrose (YES) broth.