Effect of aw and CO2 level on Aspergillus flavus growth and aflatoxin production in high moist-Lire maize post-harvest

The potential for using modified atmospheres of 25-75% CO2 (balanced with N-2) and water activity (a(w) 0.95, 0.92) to control Aspergillus flavus development and aflatoxin B, production has been evaluated (a) oil synthetic medium and (b) on maize grain during storage for up to 21 days at 25 degrees C. Oil agar medium tip to 75% CO, at both 0.95,aid 0.92 a,, significant inhibition of growth was obtained (P < 0.05). In stored grain inoculated with spores of A. flavus there was significantly higher populations of the species at 0.95 a, than 0.92 a,. Up to 75% CO2 resulted in an inhibition of the Populations of A. flavus isolated front the grain. Contrasting aflatoxin B, production was obtained on agar and in stored maize grain. Oil agar, greatest amounts were produced at 0.92 a(w), while more was produced at 0.95 a, oil maize grain. Overall, the efficacy of controlled atmospheres x aw showed that treatment with 25% CO, Could be sufficient to efficiently reduce A. flavus development but at least 50% CO2 was required to obtain a significant reduction Of aflatoxin synthesis. (c) 2007 Elsevier B.V. All rights reserved.