RESUMO
PremiTest, a microbial inhibition test for the screening of antimicrobial residues, was validated according to the criteria established by Decision 2002/657/EC. Sensitivity, detection capability (CCß), specificity, selectivity, robustness and applicability were evaluated. The methodology involves the technique of solvent extraction, which increases the detection capability of the test for a wider range of antibiotics. The following CCß values in poultry muscle were found: penicillin G ≤ 12.5 µg kg(-1), total sulfonamides ≤ 75 µg kg(-1), erythromycin 75 µg kg(-1) and lincomycin 50 µg kg(-1). The detection capability of chlortetracycline was equal to its maximum residue limit (100 µg kg(-1)) and the method did not detect gentamicin (1000 µg kg(-1)), for which no MRL is established in poultry muscle. Specificity evaluated in relation to different analytes and matrices did not detect any interferences in the tests results; whilst the robustness showed that the pH neutralisation point of the extract affects the analytical results and the kits' performance. Only the screening of tetracyclines requires the analysis of extracts without pH neutralisation. The results of the validation process showed that this method is acceptable for screening ß-lactam, sulfonamide and macrolide antimicrobial groups in the National Residues and Contaminants Control Programme (PNCRC), and that for this it is fit for purpose.
