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a b s t r a c tA three-year (2006)(2007)(2008) survey on commercial wheat grain was conducted aimed at quantifying the intensity of Fusarium head blight epidemics related to kernel quality and levels of deoxynivalenol (DON) and nivalenol (NIV). Grain samples, obtained from 38 municipalities throughout the state of Rio Grande do Sul, Brazil, were assessed visually for Fusarium-damaged kernels (FDK) and chemically using liquid chromatography-mass spectrometry (LC-MS/MS). Overall FDK mean levels were 15.5%, not differing among the years. Co-contamination was predominant (59/66) across samples and overall mean levels of DON and NIV were 540 and 337 lg/kg, respectively. When the levels of both mycotoxins were added together (DON + NIV), a higher correlation with FDK was found (R = 0.36, P < 0.01), compared to single toxin data. For the first time, the presence of NIV in levels comparable to DON is reported from a multi-year regional epidemiological survey in the country which should be of concern to the small grains industry.

Nowadays, bee products are being produced in an environment polluted by different sources of contamination, such as pesticides, which can be transported by honey bees to the hive and incorporated into honey. In addition, the increasing consumption of honey has demanded efficient quality control for this product. In this study, the determination of the pesticides fipronil, imidacloprid, thiamethoxam, dimethoate, carbendazin, tebuconazole, amitraz, τ-fluvalinate and 5-hydroxymethylfurfural (HMF) which are used as indicators of honey quality, was carried out simultaneously. For the sample preparation, the optimized QuEChERS method was used and the determinations were done by LC-APCI-MS/MS. The LOQs of the method ranged between 0.005 and 1.0 mg kg(-1). For the recovery calculations and method evaluation a working curve was drawn. All the analytical curves showed r values higher than 0.99. The recoveries ranged between 70% and 112%, with RSD lower than 20% for all compounds. The matrix effect was evaluated, and most of the compounds showed signal enrichment. The applicability of the method for honey from different flowers was verified, and the method showed robustness and recoveries in the range 70-120% established for all compounds in samples belonging to different blossoms. HMF was detected in all samples, with concentrations ranging between 4.6 and 51.7 mg kg(-1); it was below the maximum concentration allowed by the legislation.

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In this work, 12 different yeast strains were evaluated to gauge their ability to accumulate lipids using raw glycerol as the main carbon source. Lipomyces lipofer NRRL Y-1155 stood out above the other strains, achieving 9.48 g/l biomass, 57.64 % lipid content and 5.46 g/l lipid production. The fatty acid profile was similar to vegetable oils commonly used in the synthesis of biodiesel, with the predominance of polyunsaturated acids, especially linoleic acid, reaching 68.3 % for Rhodotorula glutinis NRRL YB-252. The occurrence of palmitic acid (39.3 % for Lipomyces starkeyi NRRL Y-11557) was also notable. Thus, yeast biomass with high lipid content can be a sustainable and renewable alternative as a raw material for the biodiesel industry.