Development of an immunochromatographic strip test for rapid detection of melamine in raw milk, milk products and animal feed.

A simple, rapid and sensitive immunogold chromatographic strip test based on a monoclonal antibody was developed for the detection of melamine (MEL) residues in raw milk, milk products and animal feed. The limit of detection was estimated to be 0.05 mu g/mL in raw milk, since the detection test line on the strip test completely disappeared at this concentration. The limit of detection was 2 mu g/mL (or 2 mu g/g) for milk drinks, yogurt, condensed milk, cheese, and animal feed and 1 mu g/g for milk powder. Sample pretreatment was simple and rapid, and the results can be obtained within 3-10 min. A parallel analysis of MEL in 52 blind raw milk samples conducted by gas chromatography-mass spectrometry showed comparable results to those obtained from the strip test. The results demonstrate that the developed method is suitable for the onsite determination of MEL residues in a large number of samples.