A novel glass fiber disc culture system for testing of small amounts of compounds on growth and aflatoxin production by Aspergillus flavus.

A new method for growing Aspergillus flavus for experimental studies is presented. The system consists of a humidified vial with a thick septum pierced by a pin on which a glass fiber disc is affixed. The disc contains the test solution and inoculum plus medium. The method has been used to assess the effect of variations in culture conditions on production of aflatoxin B1 (AFB1). The AFB1 level was affected by the amount of medium placed on the disc and type of disc material. The results for different types of glass fiber and quartz discs were compared with AFB1 produced by fungus grown in liquid medium or on paper discs. When compared to a liquid medium culture there was a 15 to 20-fold increase in AFB1 for one type of disc. Incubations with less than 14 microliters of medium gave satisfactory results. A crude phosphatidylcholine preparation at a concentration of 0.7% of the medium resulted in a 4-fold increase in AFB1.