Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/2/2004
Publication Date: 10/19/2004
Citation: Anis, N., Menking, D., Valdes, J., Park, J., Gotthardt, J., Khalia, M., Stanker, L.H. 2004. The use of kinexa for quantitative rapid detection of ceftiofur antibotic residues in raw milk [abstract]. First Annual Sapidyne Instruments KinExA Symposium. Paper No. ANIS. Interpretive Summary:
Technical Abstract: Contamination of milk by drug residues has the potential to represent a major public heath hazard. Current methods for residue detection are either very slow (microbial growth assay) or laborious and time consuming (e.g., HPLC, GC, or GC-MS). A simple detection system that is cost effective and user-friendly is needed for rapid screening of milk samples for drug residues. A solid-phase competitive fluoroimmunoassay using a 12 channel fully automated flow fluorometer adapted for rapid screening of ceftiofur in raw unprocessed milk was developed. The fluorescent signal was generated by the binding of fluorescein-labeled secondary antibodies (anti-mouse IgG-FITC) to a protein complex, consisting of BSA-conjugated ceftiofur and monoclonal anti-ceftiofur antibodies, immobilized on the surface of polymethyl-methacrylate (PMMA) beads. Binding of the anti-ceftiofur antibodies to the BSA-ceftiofur-coated beads was inhibited by the free ceftiofur in milk samples in a dose dependent manner. The binding of the mAb anti-ceftiofur to the BSA-ceftiofur-coated beads was specific as the mAb anti-ceftiofur was not bound to beads coated with non-specific BSA-antigen or beads coated with non-specific proteins such as casein, BSA, or IgG. The Limit of Quantitation (LOQ) of the assay was 0.3 ppb. The dynamic range of the assay was 1 ppb to 50 ppb. The assay discriminated effectively between ceftiofur which was readily detected at 5 ppb and other commonly used antibiotics which were not detected at 100 ppb. The assay provided direct, simple, rapid, and specific screening of milk samples without the sample preparation that is usually needed for residue detection by instrument analysis.