Development of a microparticle‐enhanced nephelometric immunoassay for the quantification of beta‐casein in milk

Abstract

Beta‐casein determination has been performed in cow's milk by a microparticleenhanced nephelometric immunoassay. Hydrophilic monodisperse beta‐casein coated microspheres, specifically conceived as an antigen‐antibody reaction support, are agglutinated by anti‐beta‐casein antiserum. Free beta‐casein inhibits this immunoagglutination, allowing its fast (30 min) and sensitive (1 μg l‐¹) quantification with accuracy and precision, by nephelometric measurement of the light scattered by the beta‐casein coated microsphere agglutinates. This immunoassay of beta‐casein is easy to perform in milk (no washing, no phase separation, nor sample pretreatment). Microparticle‐enhanced nephelometric immunoassay appears as an alternative method to measure a large variety of molecules in dairy analysis.

Keywords:

• Particle immunoassay
• immunonephelometry
• beta‐casein