New additive for culture media for rapid identification of aflatoxin-producing Aspergillus strains

A new reliable, fast, and simple method for the detection of aflatoxigenic Aspergillus strains, consisting of the addition of a cyclodextrin (a methyl ated beta -cyclodextrin derivative) to common media used for testing mycoto xin production ability, was developed. We propose the use of this compound as an additive for fungal culture media to enhance the natural fluorescence of aflatoxins. The production of aflatoxins coincided with the presence of a bright blue or blue-green fluorescent area surrounding colonies when obs erved under long-wavelength (365-nm) UV light after 3 days of incubation at 28 degreesC. The presence of aflatoxins was confirmed by extracting the me dium with chloroform and examining the extracts by high-pressure liquid chr omatography with fluorescence detection.