title: Detection of streptomycin residues in whole milk using an optical immunobiosensor.
abstract: The development of an assay for the detection of streptomycin residues in pasteurized whole milk using an optical biosensor (Biacore) is reported. Streptomycin-adipic hydrazide coupled to bovine thyroglobulin was used to produce a sheep polyclonal antibody. The antibody displayed excellent cross-reactivity with dihydrostreptomycin (106%). There was no significant cross-reaction with other aminoglycosides or common antibiotics. Streptomycin was also immobilized onto a CM5 sensor chip to provide a stable, reusable surface. The developed assay permitted the direct analysis of whole milk samples ( approximately 3.5% fat) without prior centrifugation and defatting. Results were available in 5 min. The limit of detection of the assay was determined as 4.1 ng/mL, well below the European maximum residue limit (MRL) of 200 ng/mL. Repeatability (or coefficient of variation) between runs was determined as 3.5% (100 ng/mL; 0.5 x MRL), 5.7% (200 ng/mL; MRL), and 7.6% (400 ng/mL; 2 x MRL).
authors.affiliation: Veterinary Sciences Division, Department of Agriculture and Rural Development, Stoney Road, Stormont, Belfast BT4 3SD, Northern Ireland.
authors.forename: G A
authors.initials: GA
authors.lastname: Baxter
authors.forename: J P
authors.initials: JP
authors.lastname: Ferguson
authors.forename: M C
authors.initials: MC
authors.lastname: O'Connor
authors.forename: C T
authors.initials: CT
authors.lastname: Elliott
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification; D015374:Biosensing Techniques; D004350:Drug Residues / Q000302:isolation & purification*; D008892:Milk / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013307:Streptomycin / Q000302:isolation & purification*
chemical_list: D000900:Anti-Bacterial Agents; D013307:Streptomycin