Beta-lactam Test Device is a semi-quantitative and rapid lateral flow assay designed to detect beta-lactam antibiotic residues in raw commingled cow’s milk.
Knowledge of Beta-lactam Test Device
The assay uses a competitive colloidal gold based format. The milk sample (500 μL) is added to a clear plastic reaction tube, and used to resuspend the lyophilized/dried reagents in the tube to a uniform solution. The milk is incubated briefly (5 min) to allow the biotinylated Beta-Lactam Binding Protein (biotin-BLaBP) to engage with any beta-lactam antibiotic present in the milk. Then the incubated milk is transfer to other sample well of the device initiating capillary flow up the strip. Any biotin-BLaBP that are not engaged with antibiotics present in the milk will bind to the Amoxicillin -BSA-Colloid Gold complex imprinted at the sample pad and form a complex biotin-BLaBP-Amoxicillin-BSA-Colloid Gold. When the complex moves to the Test line (T-line) on the NC membrane, where the streptavidin is immobilized, forming a signal (red line) at that position.
Therefore, a colored band appears in the test region when the milk is negative for the beta-lactam antibiotic. If beta-lactam antibiotic is present in the milk at a sufficient concentration, it competes with the immobilized conjugate (Amoxicillin-BSA-Colloid Gold) on the sample pad for limitedbiotin-BLaBP in the sample. This will prevent the formation of the complex (biotin-BLaBP-Amoxicillin-BSA-Colloid Gold) on the sample pad. As a result, no signal formed at the test region. Therefore, the absence of a colored band at the test region indicates a positive result. The appearance of a colored band at the control region serves as a procedural control, indicating that the proper volume of specimen has bc2een added and membrane wicking has occurred.
Procedure and Result Reading of Beta-lactam Test Device