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AACC Approved Methods of Analysis, 11th Edition - AACC Method 45-15.01. Aflatoxin -- Presumptive Test

AACC Approved Methods of Analysis, 11th Edition


AACC Method 45-15.01
Aflatoxin -- Presumptive Test


The bright greenish yellow fluorescence (BGYF) test (black light test) is used as a presumptive test to identify lots of white and yellow corn that may contain aflatoxins. Corn is inspected under ultraviolet (UV) light (365 nm) for the characteristic BGYF associated with Aspergillus flavus or A. parasiticus, the fungi that produce aflatoxins (Refs. 3, 4). If BGYF is present, indicating a positive test, corn must be further analyzed by thin-layer chromatographic, high-performance liquid chromatographic, or immunoassay methods to determine the presence and levels of aflatoxins. False negative tests rarely appear.

Growth of these fungi may or may not result in aflatoxin production. BGYF is also produced on grain sorghum or cottonseed, but usually not on seed killed by high-temperature drying. Aflatoxins do not fluoresce bright greenish yellow under long-wave UV light, but BGYF may be produced by reaction of kojic acid formed by fungi and peroxidase enzyme from the seed. BGYF test is the quickest method of detecting grain that could contain aflatoxin, requires very little equipment, and can easily be done in the field. However, a positive test does not absolutely indicate that aflatoxin is present. It identifies corn lots that should be tested for aflatoxin.