Abstract:

In order to establish a competitive ELISA method for detecting β-casein of bovine milk, the factors to affect competitive-ELISA were investigated. The optimal conditions for competitive ELISA method were coated anti-β-CN IgY concentration of 1:160, 1% gelatin-PBST as the blocking solution and blocking time of 1 h. The working titers betweenβ-CNHRP and detection samples were 1:20 and 1:80, respectively. The reaction time of antibody and antigen was 1 h and the optimum enzymatic reaction time was 20 min. Detection results indicated that the detected limit was 3.5% with a variation coefficient (CV) of less than 5%. This method can be used for rapid and accurate detection ofβ-casein in bovine milk and dairy products.

Key words: competitive ELISA, β-casein, egg-yolk antibody