IMPLEMENTATION OF THE SYSTEM OF HONEY SAFETY CONTROL ON THE EXAMPLE OF ANALYZING OF RESIDUES OF TETRACYCLINE GROUP ANTIBIOTICS

The National Reference Laboratory of Drug Residues Control has implemented a system of "classical" honey safety control based on the parameters of antimicrobial drug residues: samples testing by the screening enzyme-linked immunosorbent assay (ELISA) method and, in the case of positive or possibly positive samples occurring, – retesting by confirmatory UPLC-MS/MS multi-method developed in the laboratory. The article presents the results of ELISA screening method validation for the determination of residual amounts of tetracycline group antibiotics (tetracycline, oxytetracycline, chlortetracycline, doxycycline) in honey samples using Tetracyclin® RIDASCREEN test kits by R-Biopharm (Germany) and Oxytetracycline ELISA by EuroProxima (the Netherlands) and its verification by means of the confirmatory method. In accordance with the Commission Implementing Regulation (EU) 2021/808, the validation of test kits proposed by the manufacturers was carried out taking into account the minimum required limit of detection. The fitness-for-purpose of the methods was confirmed based on the establishment of main validation parameters for screening methods (technical threshold and cut-off factor) using control (blank) and fortified honey samples with standard solutions of tetracycline at the level of ½ of the minimum required limit of detection, according to the "added-received" criterion. The proposed methods are the simple in carrying out, time- and cost-effective, which are their main advantages. The reliability of the results obtained by the proposed methods was verified using the developed confirmatory UPLC-MS/MS multi-method. The results of comparative studies of control (blank) honey samples and fortified with a standard solution of tetracycline antibiotics at the level of 2.5 and 5.0 μg/kg, as well as the results of the interlaboratory testing with the accredited laboratory (Germany) are presented.