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Marchi C.E.,Laboratorio Nacional Agropecuario em Sao Paulo Lanagro SP | Fernandes C.D.,Embrapa Gado de Corte | Bueno M.L.,Federal University of Mato Grosso do Sul | Batista M.V.,Embrapa Gado de Corte | Fabris L.R.,Federal University of Mato Grosso do Sul
Semina:Ciencias Agrarias | Year: 2010

The sanitary quality of 26 lots commercial seeds of tropical forages, produced in different regions (2004-05 and 2005-06) was analyzed. The lots were composed of seeds of Panicum maximum ('Massai', 'Mombaça' e 'Tanzânia') and stylo ('Estilosantes Campo Grande'-ECG). Additionally, seeds of two lots of P. maximum for exportation were analyzed. The blotter test was used, at 20°C under alternating light and darkness in a 12 h photoperiod, for seven days. The Aspergillus, Cladosporium and Rhizopus genus consisted the secondary or saprophytes fungi (FSS) with greatest frequency in P. maximum lots. In general, there was low incidence of these fungus in the seeds. In relation to pathogenic fungi (FP), it was detected high frequency of contaminated lots by Bipolaris, Curvularia, Fusarium and Phoma genus. Generally, there was high incidence of FP in P. maximum seeds. The occurrence of Phoma sp. was hight, because in 81% of the lots showed incidence superior to 50%. In 'ECG' seeds it was detected FSS (Aspergillus, Cladosporium, and Penicillium genus) and FP (Bipolaris, Curvularia, Fusarium and Phoma genus), usually, in low incidence. FSS and FP were associated to P. maximum seeds for exportation, with significant incidence in some cases. The results indicated that there was a limiting factor in all producer regions regarding sanitary quality of the seeds. Source

Torres D.P.,Laboratorio Nacional Agropecuario em Sao Paulo Lanagro SP | Torres D.P.,University of Campinas | Martins-Teixeira M.B.,Laboratorio Nacional Agropecuario em Sao Paulo Lanagro SP | Silva E.F.,Laboratorio Nacional Agropecuario em Sao Paulo Lanagro SP | Queiroz H.M.,Laboratorio Nacional Agropecuario em Sao Paulo Lanagro SP
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2012

A very simple and rapid method for the determination of total mercury in fish samples using the Direct Mercury Analyser DMA-80 was developed. In this system, a previously weighted portion of fresh fish is combusted and the released mercury is selectively trapped in a gold amalgamator. Upon heating, mercury is desorbed from the amalgamator, an atomic absorption measurement is performed and the mercury concentration is calculated. Some experimental parameters have been studied and optimised. In this study the sample mass was about 100.0 mg. The relative standard deviation was lower than 8.0% for all measurements of solid samples. Two calibration curves against aqueous standard solutions were prepared through the low linear range from 2.5 to 20.0 ng of Hg, and the high linear range from 25.0 to 200.0 ng of Hg, for which a correlation coefficient better than 0.997 was achieved, as well as a normal distribution of the residuals. Mercury reference solutions were prepared in 5.0% v/v nitric acid medium. Lyophilised fish tissues were also analysed; however, the additional procedure had no advantage over the direct analysis of the fresh fish, and additionally increased the total analytical process time. A fish tissue reference material, IAEA-407, was analysed and the mercury concentration was in agreement with the certified value, according to the t-test at a 95% confidence level. The limit of quantification (LOQ), based on a mercury-free sample, was 3.0 μg kg-1. This LOQ is in accordance with performance criteria required by the Commission Regulation No. 333/2007. Simplicity and high efficiency, without the need for any sample preparation procedure, are some of the qualities of the proposed method. © 2012 Taylor & Francis. Source

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