New method for the rapid identification of tetracycline residues in foods of animal origin - using the PremiTest in combination with a metal ion chelation assay.

A post-screening classification assay for tetracycline compounds has been developed and integrated into the previously reported optimized PremiTest methodology. The new post-antimicrobial screening assay is based on a metal ion chelation using calcium and sodium chloride and has been shown to be specific towards the tetracycline class. The assay is both cost-effective and complementary to the post-screening procedures that have previously been developed for the beta-lactam and sulfonamide compounds. A validation study was conducted in accordance with 2002/657/EC (Commission Decision). The method is rugged and applicable to a range of tetracyclines of differing antimicrobial potencies over a wide concentration range. A blind trial was undertaken in which all antimicrobial residues in the unknown samples were successfully identified by the analyst following the integrated PremiTest procedure for the classification of antimicrobial compounds.