A rapid identification method for aflatoxin-producing strains ofAspergillus flavus andA. parasiticus by ammonia vapor
The colony reverse of aflatoxin (AF)-producing strains ofAspergillus flavus andA. parasiticus turned pink when their cultures were exposed to ammonia vapor. The color change was visible for colonies grown on media suitable for AF production such as potato dextrose, coconut, and yeast extract sucrose agars after 2 d incubation at 25°C. Of the 120 strains ofA. flavus, A. parasiticus, and two related species inA. flavus group:A. oryzae andA. sojae tested in this study, only the AF-producing strains ofA. flavus andA. parasiticus showed the pink pigmentation. The color change occurred immediately after the colony was contacted with ammonia vapor. This method was useful for rapid screening the AF-producing strains ofA. flavus andA. parasiticus.
Key Wordsaflatoxin-producing strains ammonia vapor Aspergillus flavus screening method
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