96T 10min High Sensitivity β-Lactams and Tetracyclines (BT) Rapid Test Strip For Milk Antibiotic Residue Detection

BT Combo Strip Test is a qualitative and rapid lateral flow assay designed to detect both beta-lactam and tetracycline antibiotic residues in raw commingled cow's milk. This test uses a tetracycline receptor and a novel beta-lactam binding protein which eliminates the need for a heating block. This test is designed for point-of-care use or reference lab settings.

C-line indicates the presence of the corresponding antibiotic in the milk. The greater the reduction in signal intensity at the test line, the greater the concentration of tetracycline or beta-lactam antibiotics present in the milk. The assay is also designed to simultaneously detect tetracycline and beta-lactam antibiotics.

The BT Combo Strip Test has the capacity for 96 determinations. The shelf life is 12 months when the kit is properly stored. The positive and negative control vials contain lyophilized raw milk samples, and must be reconstituted with 1 mL of distilled water before use. The positive control vial is spiked with 4 ppb Penicillin G and 100 ppb of Oxytetracycline. The reconstituted raw milk controls are stable for 48 hours at 4℃. Additional positive and negative control vials are available separately.

The assay uses a competitive colloidal gold based format. The milk sample (200 μL) is added to a clear plastic reaction vessel, and used to resuspend the lyophilized reagents to a uniform pink color in the bottom of the microtiter wells. The milk is incubated briefly (3 min) to allow the both antibiotic binding proteins on the gold particles to engage with any antibiotic present in the milk.

The test strip is then inserted into the sample well with the arrows pointing downward initiating capillary flow up the strip. Any gold particles that are not complexed with antibiotics present in the milk will bind to their respective test line, forming a signal (red line) at that position. Each test strip is imprinted with two test lines and one Control line (C-line). One test line allows for the detection of tetracyclines, and the other for the detection of beta-lactam antibiotics.

If the binding protein on the gold particle has engaged with either a tetracycline or a beta-lactam antibiotic present in the milk sample, the gold particle will flow past the test line corresponding to that antibiotic and reach the C-line. For visual interpretation of the test results, any test line signal intensity that is stronger than the signal at the C-line indicates a negative result. Signal at any test line which is equal or less intense compared to the C-line indicates a positive result.