THE DEVELOPMENT AND THE VALIDATION OF THE METHOD FOR TRIMETOPRIM RESIDUES DETERMINATION IN TISSUES SAMPLES USING THE METHOD OF ENZYME-LINKED IMMUNOSORBENT ASSAY

The article presents the results of the development of sample preparation method of muscle and parenchymal tissues for their further testing on trimethoprim residues by enzyme-linked immunosorbent assay using Trimethoprim test kits from Kwinbon Biotechnology (China), designed to analyze another target matrix, viz. honey. The results of the comparison of sample preparation methods with the use of different techniques of analyte extraction from tissues, with the established percentage of extraction are presented. The most effective conditions are proposed: acetonitrile extraction using ultrasonic intensification, subsequent concentration of the analyte by evaporation, reconstitution of dried residue and degreasing. This approach makes it possible to determine trimethoprim residues in poultry tissues at the level of 5-10 μg/kg with an absolute recovery of about 75%. In accordance with the Decision of the European Commission 2002/657/EC, the validation of the proposed method was carried out taking into account the maximum permissible levels (MRL) of trimethoprim in the tissues of productive animals. The suitability of the method was confirmed on the basis of establishing of the main validation parameters for screening methods (technical threshold and cut-off factor) using control (pure) and spiked with a standard solution of trimethoprim at the level of ½ MRL samples of muscle and parenchymal tissues of broiler chickens. The main advantages of the developed technique are simplicity of performance, rapidity and cost effectiveness. The certainty of the results obtained using the developed method was verified using the confirmatory UPLC-MS/MS method. The article presents the results of a comparative study of pure samples of broiler chickens muscles and parenchymal tissues and spiked at the level of ½ MRL with a standard solution of trimethoprim. The developed screening technique of enzyme-linked immunosorbent assay is recommended for determination of residual amounts of trimethoprim in tissue samples and can be used for routine laboratory tests, as well as to study the withdrawal procedure of veterinary drugs based on this drug.

Pesticide residues determination in food premises in Bench-Maji zone, Southwest Ethiopia

Pesticides are very important risk factors in human life causing chronic human health effects. Pesticides are commonly used across the globe to enhance human endeavors. In Ethiopia, pesticides are widely used by local farmers and governmental organizations for pests control purpose. However, majority of pesticides are not specifically targeting the pest. As a result, pesticide residues in food items have been a concern to the consumers and environment they live in. Therefore, this study was aimed to determine the amount of organo-chlorine and organo-phosphate pesticide residues in cereal crops in Bench-Maji Zone, Ethiopia. Experimental study design was employed to determine the amount of pesticide residues and cereal crops were bought from the local farm sites and market of purposively selected sites. The samples were extracted using a Quick, Easy, Cheap, Effective, Rugged and Safe extraction and clean up method. Finally, the extracted samples were injected into Gas chromatography tandem Mass Spectrometer and the types, and concentrations of pesticide residues were analyzed using linear regression equation that obtained from calibration curves. The highest concentration of Endosulfan sulfate (0.076 mgkg− 1) was detected in rice, followed by Dimethoate (0.068 mgkg− 1) and p,p’-DDE (0.087 mgkg− 1) in Sorghum and common millet, respectively in the samples obtained from Gurafarda site. The highest concentration of p,p’-DDT (0.133 mgkg− 1) was detected in common millet, followed by Aldrin (0.082mgkg− 1) and Dimethoate (0.077mgkg− 1) in Sorghum and common millet, respectively in the samples obtained from North-Bench site. In addition, Aldrin detected in rice, sorghum and common millet obtained from the three sites was a residue of above the maximum residual limits set by Codex Alimentarius regulations and European Union. The finding shows that the detection of pesticide residues in cereal crops in samples obtained from the study area. It is an indication of the widespread use of pesticides in cereal crops production. Therefore, strict supervision of pesticide application in the fields, regulation of informal veterinary drug store and implmentation of integrated vector management strategy are recommended.

Safety of imported agricultural products: pesticide residues

Introduction. From the evaluation of the positions of residual quantities of pesticides, the hygienic safety assessment of imported food products is most relevant under the current agreement on a free trade zone between the EAEU and the Socialist Republic of Vietnam, as well as in connection with a large list of chemical plant protection products used during the vegetation of crops. The purpose of the study. Rating the level of residual quantities of pesticides in samples of selected food products produced in Vietnam is the purpose of the study. Research objectives. To quantify 42 active ingredients of pesticides (and their metabolites) in samples of rice grain, dragon fruit (pitahaya), avocado, mango and banana (fresh and dried) are the research objectives. Material and methods. Multicomponent and individual methods based on LC and GC with MS-detection and FLD were used to identify active ingredients of pesticides. The sample preparation procedure with QuEChERS technology was used for the multi residues determination of the 40 compounds. The determination of avermectins (abamectin and emamectin benzoate) was carried out after the conversion of substances into fluorogenic derivatives. Results. Residual amounts of tebuconazole (rice - 0.53 ppm, mangoes - 0.26 ppm, avocado - 0.15 ppm), fludioxonil (rice - 0.017 ppm), imidacloprid (dried mangoes - 0.01 ppm), carbendazim (dried mangoes - 0.011 ppm) were identified in single samples No residual avermectins have been identified. The content of substances in the analyzed samples of dragon fruit (pitahaya) did not exceed 0.01 ppm. Discussion. The results obtained in the work are compared with the data of the annual pan-European and national monitoring, information on which is publicly available (2017), including imported goods, according to which rice and dragon fruits as objects of monitoring are given increased attention. Conclusions. The safety of certain types of food products imported from Vietnam is shown by the content of residual quantities of pesticides.