Crescimento de Aspergillus flavus e produção de aflatoxina em grãos de milho armazenados sob diferentes temperaturas

• Autor(a) principal: Travaglia, Diana Paris
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3584
• topic: Aspergillus flavus; Aflatoxina; Milho; Aspergillus flavus; Aflatoxin; Corn; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA

Mycotoxins are secondary metabolites of the metabolism of fungi and can be immunosuppressive, potentially carcinogenic, teratogenic and mutagenic. Among them, aflatoxins are the most potentially carcinogenic. The best way to prevent the production of mycotoxins is to control the factors that allow the development of fungi. Thus, the objective of this study was to determine the growth of the fungus Aspergillus flavus and the production of total aflatoxina (B1, B2, G1 and G2) in culture medium Yeast Extract Sucrose (YES) and maize grains stored for 14 days, in an environment with equilibrium relative humidity of 90%, at temperatures of 3, 10, 15, 20, 25, 30 and 42 °C. Four repetitions were used and the results were analyzed descriptively using simple average and standard deviation. On the 4th day of incubation in medium YES, the diameter of fungal growth at 15, 20, 25, 30 and 42 °C was 4, 20, 56, 81 and 19 mm respectively, and at 5 and 10 °C was not observed growth. However, the production of total aflatoxin, performed only in the 14 th day of incubation, only occurred in this medium at temperatures of 25 and 30 °C, at concentrations of 8,7 and 10,3 μg.kg-1, respectively. In maize, on the 14th day of storage, the visual growth of A. flavus was observed in all samples stored at 20, 25 and 30°C, and in half of the samples at 42 °C. Production of total aflatoxina in maize grain was detected at 15, 20, 25, 30 and 42 °C at concentrations of 4,6; 899,2; 5.104,0; 5.654,0 e 63,7 μg.kg-1, respectively. Thus, for the experimental conditions can be conclude that, in the medium YES, the Aspergillus flavus is able to grow at different temperatures and it capacity to produce aflatoxina total is higher in temperature of 30 °C. And, in maize, this microorganism is able to grow at different temperatures and to produce greater quantity of total aflatoxin in storage environment with temperature of 30 °C for the same value of equilibrium relative humidity.