Evaluation of the mycoflora and aflatoxins from the pre-harvest to storage of peanuts: a case study/ Avaliacao da micoflora e aflatoxinas da producao ao armazenamento de amendoim: estudo de caso

Aflatoxins are carcinogens produced by Aspergillus Jlavus, A. parasiticus and A. nomius. In the present study, peanut samples were collected at different phenological stages of the plant during the 2007/2008 and 2008/2009 seasons and from stored peanuts harvested in 2007/2008. The mycoflora and aflatoxins in the peanuts were evaluated. The results showed the presence of Fusarium spp., Macrophomina spp., Trichoderma spp., Aspergillus spp. and Cladosporium spp. during the period of peanut maturation (39.8, 17.9, 8.2, 2.7 and 1.7%, respectively) and storage (49.8, 27.8, 12.5, 8.8 and 1.0%, respectively). However, aflatoxins were not detected in the samples. Of the 25 Aspergillus spp. isolates, 24 (96%) were producers of aflatoxin [B.sub.1] (96%), 10 (40%) of aflatoxin [B.sub.2], 17 (68%) of aflatoxin [G.sub.1], and 10 (40%) of aflatoxin [G.sub.2]. The isolation of Aspergillus spp. during storage was not influenced by the temperature, relative humidity or water activity (p > 0.05). The detection of aflatoxin-producingAspergillus spp. in the samples analysed at different phenological stages, aerial gynophore, pod filling (seeds), mature fruits (pod), and dry fruits (harvest), indicates the importance of good agricultural practices from the cultivation to storage of peanuts in southern Brazil. Keywords: mycotoxins, fungi, Aspergillus spp., toxigenic potential, Arachis hypogaea L. Aflatoxinas sao metabolitos carcinogenicos produzidos pelo Aspergillus Jlavus, A. parasiticus e A. nomius. No presente estudo, amostras de amendoim foram coletadas em diferentes estagios fenologicos da planta durante as safras de 2007/2008 e 2008/2009, bem como no periodo de armazenamento do amendoim referente a safra de 2007/2008. A micoflora e os niveis de aflatoxinas foram determinados. Os resultados demonstraram a presenca de Fusarium spp., Macrophomina spp., Trichoderma spp., Aspergillus spp. e Cladosporium spp. no periodo de maturacao (39,8; 17,9; 8,2; 2,7 e 1,7%, respectivamente) e no armazenamento (49,8; 27,8; 12,5; 8,8 e 1,0%). As aflatoxinas nao foram detectadas nas amostras coletadas. Dos 25 isolados de Aspergillus spp., 24 foram produtores de aflatoxina [B.sub.1] (96%), 10 de [B.sub.2] (40%), 17 de [G.sub.1] (68%) e 10 de [G.sub.2] (40%). O isolamento de Aspergillus spp. durante o armazenamento nao foi influenciado pela temperatura, umidade relativa e atividade de agua (p > 0,05). A deteccao de Aspergillus spp. produtores de aflatoxinas nos diferentes estagios fenologicos: g