Effect of climatic conditions on natural mycoflora and fumonisins in freshly harvested corn of the State of Paraná, Brazil.

Autor: Ono, Elisabete, Sugiura, Yoshitsugu, Homechin, Martin, Kamogae, Márcia, Vizzoni, Édio, Ueno, Yoshio, Hirooka, Elisa
Zdroj: Mycopathologia; Aug1999, Vol. 147 Issue 3, p139-148, 10p
Abstrakt: Natural mycoflora associated with fumonisins were analyzed in 150 samples of freshly harvested corn from Central-Southern, Central-Western and Northern regions of the State of Paraná, Brazil and correlated to climatic conditions. The corn samples were frequently contaminated with Fusarium sp.(98.7 to 100%) and Penicillium sp. (93 to 100%), when compared to Aspergillus sp. (not detected to 27.7%). The highest contamination with potentially mycotoxigenic fungi occurred in corn harvested in the Central-Western region, where total mould and yeast counts ranged from 5.5 × 103 to 5.2 × 106 CFU/g, with 98.7% contaminated by Fusarium sp. and 93% by Penicillium sp. In this region F. moniliforme ( F. verticillioides) was the predominant Fusariumsp., and was isolated in 85.9% of the samples. Aspergillus sp. was isolated from 27.7% samples. FB1 was detected in 100% of the samples (mean of 2.39 μg/g) and FB2 in 97.7% (mean of 1.09 μg/g). Fumonisins were also detected in all samples from Northern region, with mean of 4.56 μg/g (FB1) and 2.20 μg/g (FB2).Considering 1.0 μg/g as the threshold, 72% of the corn samples from the Central-West and 92% from the North were contaminated with concentrations above this value, in contrast to a 18.5% contamination rate from Central-Southern samples. Between corn planting to harvesting season, the average maximum temperature and relative humidity were 26 °C and 77.1%(Central-Southern), 27 °C and 69% (Northern)and 29.9 °C and 89.1% (Central-Western).Therefore, the higher fumonisins contamination of corn from Northern region when compared to the Central-South were due to the differences in rainfall levels (92.8 mm in Central-Southern, 202 mm in Northern) during the month preceding harvest. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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