MICROBIOLOGICAL QUALITY OF CORN GRAIN STORED IN STEEL SILOS AND DRIED UNDER FORCED NATURAL AIR

Abstract

The study aimed to evaluate the microbiological quality of corn grains stored and dried under forced natural air in three steel silos. In each silo, 4200kg of grains were placed, presenting 17.8%, 18.9% and 20.5% humidity. The evaluations were carried out at harvest time, at the end of the drying process and during the storage, at 60, 160, and 260 cm from the bottom of the silo. Water loss in greenhouse at 105 ºC, incidence of fungus in BSA environment and the occurrence of aflatoxins and fumonisins by CLAEEM were evaluated. Grains with 17.8%, 18.9% and 20.5% resulted in average humidity of 12.5%, 12.8% and 13.0%, respectively, after 22 days of drying, revealing that the process is technically feasible. The highest value observed for fumonisin (FB1) was 20257 μg kg-1 at 160 cm of silo A, and for aflatoxin B1 was 192 μg/kg at the end of the drying process. The drying of corn grains under natural forced air enabled the preservation of the microbiological quality, which permits to recommend the process for steel silos.

Keywords

• Zea mays
• fungi
• drying
• mycotoxins
• storage