Distinction between glycomacropeptide and β-lactoglobulin with ‘stains all’ dye on tricine SDS-PAGE gels.

Abstract

A competitive lateral flow immunoassay using amorphous carbon nanoparticles (CNPs) and nonimmunoglobulin antigen has been developed for the rapid detection of adulteration of cow’s milk with buffalo’s milk. Purified polyclonal antibodies against a specific buffalo’s milk protein fraction were conjugated to CNPs and sprayed on a conjugate pad. The test line consisted of buffalo’s skimmed milk proteins (1.6 μg/cm), while the control line contained anti-rabbit antibodies raised in goat (0.5 μg/cm). In the test procedure milk sample is mixed with 100 mM borate buffer (pH 8.8 containing 1% BSA and 0.05% Tween 20) and pipetted onto the sample-cum-conjugate pad. A black/grey test line can be observed if the sample is free from buffalo’s milk. The sensitivity of the test i.e. no visible test line is 5% adulteration of cow’s milk with buffalo’s milk. The test has applicability at the milk receiving stations and can be applied to heated milk samples.