Pesticides in rice-based products commercialised in Argentina.

People with coeliac disease have a limited diet. Therefore, rice-based products are an ideal alternative. Highlighting this import item, an analytical methodology was validated to determine pesticides in rice-based product samples. The precision was satisfactory for all pesticides since the RSD did not exceed 13% in any case. Regarding recovery, the method had values close to 100%. The limit of quantification was established at 10 µg/kg and the expanded uncertainty was less than 20%. After validation, 80 samples of toasts and rice crackers were analysed. All samples were compliant with the national regulations for dichlorvos and tebuconazole. The pesticide that was present in the highest number of samples was pirimiphos - methyl, but all below the maximum residue limit. From all samples analysed, 38 were positive for at least one pesticide and only one contained four pesticides simultaneously: deltamethrin, pirimiphos-methyl, kresoxim-methyl and epoxiconazole.

Mycofumigation of postharvest blueberries with volatile compounds from Trichoderma atroviride IC-11 is a promising tool to control rots caused by Botrytis cinerea.

Botrytis cinerea, the causal agent of the gray mold, is a filamentous fungus that infects blueberries and can cause important production losses in postharvest storage. Considering that the use of synthetic fungicides is not allowed on blueberries in postharvest conditions, alternative and natural strategies are needed to control gray mold. The objective of this work was to evaluate the capability of volatile organic compounds (VOCs) produced by Trichoderma atroviride IC-11 to control B. cinerea growth in blueberries after harvest. These VOCs inhibited almost completely B. cinerea growth in vitro. The most abundant volatile compound was 6-pentyl-α-pyrone (6PP). In vitro assays with pure 6PP confirmed its antifungal activity. The incidence of gray mold was evaluated in blueberries inoculated with B. cinerea and exposed to volatiles of T. atroviride IC-11. Gray mold incidence among those stored in air at 20 °C for 14 days was 100%, while the incidence among the volatile-treated fruit was 17%. Gray mold incidence among those stored in air at 4 °C for 31 days was 82%, while the incidence among the volatile-treated fruit was 11%. T. atroviride IC-11 VOCs inhibited mycelial growth and conidia germination of B. cinerea. The binding of VOCs to the surface of hyphae caused their vacuolation and deterioration. Selective cytotoxicity of 6PP on B. cinerea was observed but not on human intestinal cells at specific concentrations that controlled gray mold. The postharvest mycofumigation of blueberries with T. atroviride IC-11 VOCs is a promising approach to protect these fruits from gray mold.

Optimization of a rice cooking method using response surface methodology with desirability function approach to minimize pesticide concentration.

Rice is contaminated with pesticides applied in pre and post-harvest. These contaminations could be reduced through household operations like washing and cooking. Therefore, in the present research, a pre-soaking rice cooking method was used to reduce pesticides residues. Response Surface Methodology with Central Composite Design was applied to minimize pesticides concentration by choosing the best soaking time and water:rice grain relation before cooking. A quadratic polynomial equation was obtained. Desirability function approach gave the optimal cooking conditions as 14 h soaking time and water:rice grain relation of 3. This process allowed a pesticide elimination of 100.0%, 93.5%, 98.4%, 98.5%, 99.0%, and 95.0%, of azoxystrobin, cyproconazole, deltamethrin, epoxiconazole, kresoxim-methyl and penconazole, respectively.

Effect of household rice cooking on pesticide residues.

This investigation shows the pesticide distribution and reduction using three common household cooking methods. Extraction was performed using QuEChERS and solid phase microextraction methodologies for rice and water, respectively. Gas chromatography-mass spectrometry was used. Both methods showed good linearity (r2 > 0.9996 and 0.9945), adequate recoveries (between 98.9 and 107.8% and 90.5-104.2%) and relative standard deviations lower than 4.5% and 7.0%, for rice and water, respectively. The initial concentration of deltamethrin, penconazole, kresoxim-methyl, cyproconazole, epoxiconazole and azoxystrobin, were 84.9, 242.2, 298.5, 230.7, 253.4 and 293.5 µg/kg, respectively. Washing and soaking water reduce pesticides only 0.40 to 4.28%. The pesticide reduction during cooking were 20.73 to 57.72%, 32.74 to 70.39%, and 68.87 to 87.50% for traditional, excess water, and pre-soaking rice methods, respectively. Pre-soaking rice with extra water before cooking proved to be the method that generates the greatest reduction.

Pesticides in randomly collected rice commercialised in Entre Ríos, Argentina.

An analytical method for determination of azoxystrobin, cyproconazole, deltamethrin, epoxiconazole, kresoxim-methyl, and penconazole in rice, using QuEChERS extraction and a gas chromatography, was validated. Recoveries ranged within the 98.9-107.8 % range for all pesticides. Limits of detection and of quantification were 0.27 and 0.90 µg/kg for azoxystrobin, 0.26 and 0.88 µg/kg for cyproconazole, 0.25 and 0.84 µg/kg for deltametrhin, 0.22 and 0.72 µg/kg for epoxiconazole, 0.22 and 0.73 µg/kg for kresoxim-methyl and 0.23 and 0.77 µg/kg for penconazole, respectively. The expanded measurement uncertainty was lower than 20% for all pesticides. The occurrence of these pesticides was evaluated in 100 rice samples commercialised in different supermarkets. Residues of at least two pesticides simultaneously were found in 94 samples. The concentrations were lower than European and Argentinean legislative limits, with exception of epoxiconazole that in 36 rice samples was found in concentrations above the limit established in Argentina.