title: Residue analysis of tetracyclines in poultry muscle: shortcomings revealed by a proficiency test.
abstract: A proficiency test for tetracycline drug residues in poultry muscle was organized according to the guidelines of International Laboratory Accreditation Cooperation (ILAC) ILAC-G13:2000 (2000). For the proficiency test, three test materials were prepared. The homogeneity and stability of the materials during the study were demonstrated. Sixteen laboratories accepted the invitation to participate in the proficiency test; 11 laboratories reported results within the time frame of the study. Most notably, only four of the participating laboratories complied with the definition of the maximum residue limit (MRL) concerning the inclusion of 4-epimers as stated in European Commission Regulation 281/96 (1996). Most participants reported values for the decision limit (CCalpha) and detection capability (CCbeta) and hence were already in compliance with European Commission 2002/657/EC (2002) for this aspect of method validation. However, some CCalpha and CCbeta values were not in agreement with the actual within-laboratory reproducibility calculated from the results reported in this proficiency test. Although most laboratories obtained satisfactory results, it is clear that an effort is needed to include 4-epiOTC, 4-epiTC and 4-epiCTC in the analytical methods. Moreover, reconsideration of values determined for CCalpha and CCbeta with respect to their accuracy may be necessary in some cases.
authors.affiliation: RIKILT - Institute of Food Safety, Bornsesteeg 45, PO Box 230, NL-6700 AE Wageningen, The Netherlands. bjorn.berendsen@wur.nl
authors.forename: B J A
authors.initials: BJ
authors.lastname: Berendsen
authors.forename: J A
authors.initials: JA
authors.lastname: Van Rhijn
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis*; D004350:Drug Residues / Q000032:analysis*; D005062:European Union; D005504:Food Analysis / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D009132:Muscles / Q000737:chemistry*; D011200:Poultry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013754:Tetracyclines / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D013754:Tetracyclines