Control of residues of antimicrobial substances by screening methods in raw milk based on participation in proficiency tests in Poland, 2017–2021

Abstract

Proficiency testing (PT) is an important tool for evaluation of the competences of laboratorieswhich test milk for residues of antimicrobial substances. It also warrants the reliability ofthe obtained test results, which is important to the clients of a laboratory. In 2017–2021, the PolishNational Reference Laboratory organized 10 rounds of proficiency testing on raw milk samplesaccording to the ISO/IEC 17043 standard. The milk samples were fortified with selected antimicrobialsubstances. All participating laboratories used commercial receptor and/or microbiological diagnostickits in the proficiency tests. The results obtained by the laboratories were compared to assignedresults and were defined as compliant or non-compliant. In total, 7533 results were obtained, and104 (1.4%) were assessed as non-compliant. The percentage of laboratories which obtained a positiveresult in proficiency tests ranged by testing round from 81.8% to 100%. Based on proficiency testingresults, it can be concluded that laboratories carry out tests correctly. The proven proficiency by alaboratory increases the confidence of its clients in its service of antimicrobial residue monitoringin milk.