PRODUCTION OF AFLATOXINS B-1, B-2, G(1), AND G(2) IN PURE AND MIXED CULTURES OF ASPERGILLUS-PARASITICUS AND ASPERGILLUS-FLAVUS

Production of aflatoxins B-1, B-2, G(1), and G(2) in pure and mixed cu ltures of Aspergillus parasiticus and aspergillus flavus were compared . Differing percentages of A. parasiticus (NRRL 2999) and A. flavus (N RRL 5520) conidia were used as inoculum and allowed to grow in static liquid culture for 10 days. The pure and mixed cultures of A. parasiti cus/A. flavus were extracted and the aflatoxins partially purified. Hi gh-performance liquid chromatography was then used to determine aflato xin concentrations. The maximal decreases of G(1) and G(2) production occurred when the inocula went from 0 to 12.5% or 25% A. flavus. Aflat oxins G(1) and G(2) comprised less than 10% of the total aflatoxins wh en the A. parasiticus/A. flavus inocula contained greater than 25% A. flavus. Production of aflatoxins B-1 and B-2 increased slightly as the percentage of A. flavus in the A. parasiticus/A. flavus mixed inoculu m increased. A. flavus is apparently capable of suppressing accumulati on of aflatoxins G(1) and G(2) by A. parasiticus when these fungi are grown in mixed culture.