Biocontrol strategy at pre-harvest stage for reducing AFB1 in maize during storage in Argentina

ALANIZ ZANON, M. S.; BOSSA, M.; CHIOTTA, M. L.; ODDINO, C.; GIOVANINI, D.; CARDOSO, M. L.; BARTOSIK, R. E.; CHULZE, S. N.

Workshop; International Commission on Penicillium and Aspergillus & International Commission on Food Mycology; 2022

Maize (Zea mays L.) is an important crop in Argentina. Aspergillus flavus can infect maize at growing stage and contaminate kernels with aflatoxins (AFs), whose levels may increase during storage. In Argentina silo bags are widely used. Biocontrol based on competitive exclusion by atoxigenic A. flavus strains is a useful tool for AFs management at pre-harvest stage. In the present study the effect of pre-harvest treatments on AFB1 accumulation in maize stored in silo bags during 3 and 6 months was evaluated. Three bioformulates were applied at field stage: A. flavus AFCHG2 and ARG5/30 strains, as single and mixed inocula. Harvested kernels were stored in non-hermetic and hermetic silo bags. At t0 , t3 and t6 different parameters were evaluated: damage kernels, moisture content, aw , Aspergillus section Flavi presence, relative humidity, O2 and CO2 levels into the bags, and AFB1 levels. The biocontrol strains were able to infect maize kernels during the field trial and displaced toxigenic native isolates. At t0 control plots showed 10.9 ± 0.4 μg/kg of AFB1 while no AFB1 was detected in all the treatments. Along the storage assay AFB1 levels varied from not detected (