Fluorescent microspheres lateral flow assay for sensitive detection of the milk allergen casein

Abstract

Casein is a type of allergen that may elicit an allergic response in some people. This study developed a competitive lateral flow assay by using fluorescent microspheres (FMs) as label to rapidly and quantitatively detect casein in milk. The limit of detection (LOD) of casein in defatted milk was 100 ng/mL with a good linear range from 100 to 10,000 ng/mL. The average recoveries for intra- and inter-assay ranged from 89.03% to 93.47% and 87.69% to 92.73%, respectively, with corresponding coefficient of variance (CV) of 5.2–7.8% and 6.2–8.5%. The LOD and the CV of FMs lateral flow assay (FMs-LFA) were lower than those of the colloidal gold lateral flow assay used to quantitatively detect casein. Based on the results of enzyme linked immunosorbent assay, our conclusion is that FMs-LFA can be potentially used in the food industry.