Evaluation of viability of Aspergillus flavus and aflatoxins degradation in irradiated samples of maize

被引:40
作者
Aquino, Simone
Ferreira, Fabiane
Baggio Ribeiro, Deise Helena
Correa, Benedito
Greiner, Ralf
Casanas Haasis Villavicencio, Anna Lucia
机构
[1] Univ Sao Paulo, Dept Microbiol, Inst Ciencias Biomed, BR-05508900 Sao Paulo, Brazil
[2] IPEN, Ctr Tecnol Radiacoes, Lab Deteccao Alimentos Irradiados, Sao Paulo, SP, Brazil
[3] Fed Res Ctr Nutr & Food, Ctr Mol Biol, Karlsruhe, Germany
关键词
gamma radiation; Aspergillus flavus; fluorescent viability test; water activity; maize;
D O I
10.1590/S1517-83822005000400009
中图分类号
Q93 [微生物学];
学科分类号
071005 ; 100705 ;
摘要
One of the currently most important fungi in stored grains is Aspergillus flavus, which produce aflatoxins. This fungus can grow on diverse substrates and represents a serious public health and animal nutritional problem. Therefore, the study of techniques that can be applied to the control of aflatoxins is of great importance. The objective of the present study was to determine the effects of gamma radiation on the growth of Aspergillus flavus Link and on degradation of aflatoxin B-1 and B-2 (AFB(1) and AFB(2)) at a relative humidity of 97-99% and a water activity (A(w)) of 0.88- 0.94. Samples of corn grains were irradiated using a cobalt 60 source emitting gamma rays at doses of 2, 5 and 10 kGy. Irradiation was found to be effective in reducing the number colony-forming units of A. flavus, per gram, in the corn samples analyzed. In addition, the fluorescent viability test (fluorescein diacetate and ethidium bromide) revealed a decrease in the number of viable cells with increasing irradiation doses and three different fluorescence patterns. Furthermore, irradiation induced a partial reduction in AFB1 and AFB2 levels at the doses of 2 and 5 kGy, whereas complete degradation of aflatoxins was observed in the assay employing 10 kGy.
引用
收藏
页码:352 / 356
页数:5
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