Application of a luminescent bacterial biosensor for the detection of tetracyclines in routine analysis of poultry muscle samples
Pikkemaat, M.G. ; Rapallini, M.L.B.A. ; Karp, M.T. ; Elferink, J.W.A. - \ 2010
Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 27 (2010)8. - ISSN 1944-0049 - p. 1112 - 1117.
screening methods - sensor strain - antibiotics - residues - kidney - genes - assay - meat
Tetracyclines are extensively used in veterinary medicine. For the detection of tetracycline residues in animal products, a broad array of methods is available. Luminescent bacterial biosensors represent an attractive inexpensive, simple and fast method for screening large numbers of samples. A previously developed cell-biosensor method was subjected to an evaluation study using over 300 routine poultry samples and the results were compared with a microbial inhibition test. The cell-biosensor assay yielded many more suspect samples, 10.2% versus 2% with the inhibition test, which all could be confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Only one sample contained a concentration above the maximum residue limit (MRL) of 100 mu g kg-1, while residue levels in most of the suspect samples were very low (10 mu g kg-1). The method appeared to be specific and robust. Using an experimental set-up comprising the analysis of a series of three sample dilutions allowed an appropriate cut-off for confirmatory analysis, limiting the number of samples and requiring further analysis to a minimum
Rapid Detection of Tetracyclines and Their 4-Epimer Derivatives from Poultry Meat with Bioluminescent Biosensor Bacteria
Virolainen, N.E. ; Pikkemaat, M.G. ; Elferink, J.W.A. ; Karp, M.T. - \ 2008
Journal of Agricultural and Food Chemistry 56 (2008)23. - ISSN 0021-8561 - p. 11065 - 11070.
tet repressor - sensor strain - residues - milk - performance - resistance - tests
Tetracycline (TC) specific luminescent bacterial biosensors were used in a rapid TC residue assay sensitized to meet the EU maximum residue limit (MRL) for TC residues in poultry muscle tissue (100/mu g kg(-1)) by membrane-permeabilizing and chelating agents polymyxin B and EDTA. Sensitivities of 5 ng g(-1) for doxycycline, 7.5 ng g(-1) for chlortetracycline, and 25 ng g(-1) for tetracycline and oxytetracycline were reached. Except for doxycycline, the MRLs of these tetracyclines include their 4-epimer metabolites. In the biosensor assay, all four 4-epimers showed induction capacity and antimicrobial activity, and antimicrobial activity was also observed in the inhibition assay, although with lower efficiency than that of the corresponding parent compound in both assays. The biosensor assay is an inexpensive and rapid high-throughput screening method for the detection of 4-epimer TC residues along with their parent compounds.