• aflatoxin B1;
  • biological competence;
  • fumonisin B1;
  • natural substrate


Production of aflatoxin B1 and fumonisin B1 in pure and mixed cultures of Aspergillus flavus and Fusarium proliferatum were determined on irradiated maize seeds inoculated with different spore concentrations at 0.97 water activity (aw) and a temperature of 25 °C. The highest levels of aflatoxin B1 were produced by A. flavus at the lowest levels of inoculum (103 spore ml−1). There was no spore concentration influence on fumonisin B1 production after 10, 20 and 35 days of incubation. When A. flavus was co-inoculated with F. proliferatum, aflatoxin B1 production was inhibited. The higher the inocula levels of Fusarium produced, the higher the inhibition and this inhibition increased during the incubation period. Total inhibition was reached at 35 days of incubation. There was no interaction influence on fumonisin B1 production at all inoculum levels assayed. These results suggest that under optimal environmental conditions of substrate, water activity and temperature, the interaction between A. flavus and F. proliferatum could produce inhibition of aflatoxin B1 and stimulation of fumonisin B1. Copyright © 1999 John Wiley & Sons, Ltd.