Occurrence of aspergillus flavus strains aflatoxins in corn from Santa Fe, Argentina / Incidencia de cepas de aspergillus flavus y aflatoxinas en maíz de Santa Fe, Argentina

RESUMO

It has been demostrated in several agricultural regions all around the world that Aspergillus flavus can infect corn grains and produce aflotoxins even before the harvest. It is also known that the incidence and levels of contamination of cereals factora. In the present work, the incidence of aflotoxins in corn grain from the central and northern areas os Santa Fe province in Argentina was studied. The relationship between the extent of kernel infection by the fungus and the persence of aflotoxins in the samples was examinated. The isolation and identification of A.flavus were carried aot by plating dilutions of the ground kernels on dichloran-rose bengal-chloramphenicol agar (DRBC). Simultaneously, kernels were superficially sterilized with 10 per cent commercial CIONa and planed on potato-dextrose-chloramphenicol agar (PDA+C). The analysis of aflatoxins B1, B2 G1 and G2 was performed by thin layer chromatography (TLC) according with Norma IRAM 14803 (Argentina). A.flavus Link Fr. was identified in 63.3 per cent of the corn samples. Colonized kernels ranged from 2.5 to 25 per cent and counts on DRBC were in the order of 10 elevado a la 3 CFU/g. Two samples colonized by A.flavus contained aflatoxins B1 and B2 (50 µg/kg of aflotoxins B2, respectively). One sample contained only aflatoxins B1 (22 µ/Kg). According to these results, it may concluded that the incidence of A.flavus observed constitutes a call in attention with respect to the conditions required for storage and transportation of the grains, to minimize the proliferation of the fungus and the production of aflatoxins in these atages. Although the incidence of aflotoxins in the samples of agrains was rather low, the levels of aflotoxins Bi recorded in the samples were higher than those recommended or given as adivsory levels for human foods, by most countries in the world