Quantification of Selected Serum Proteins of Milk by Immunological Procedures

Abstract

Evaluation was of these immunological procedures for the quantification of the bovine serum albumin and β-lactoglobulin content of milk: Oudin's single diffusion, Mancini's radial immunodiffusion, and Laurell's electroimmunodiffusion techniques. All three methods were reproducible and did not require preliminary treatment of the milk. The bovine serum albumin content (mg/ml) of 25 different herd and bulk milk samples ranged from .17 to .32 by single immunodiffusion, .18 to .32 by radial immunodiffusion, and .16 to .31 by electroimmunodiffusion. Means were .250, .258, and .238. The concentration (mg/ml) of β-lactoglobulin for 15 milk samples ranged from 2.9 to 3.9 by single immunodiffusion, 2.8 to 4.0 by radial immunodiffusion, and 3.0 to 4.1 by electroimmunodiffusion. Means were 3.44, 3.45, and 3.50. The minimum amount of protein detected by each procedure was 7.5μg bovine serum albumin or 6.25μg β-lactoglobulin by single immunodiffusion, .75μg bovine serum albumin or β-lactoglobulin by radial immunodiffusion, and .025μg bovine serum albumin or β-lactoglobulin by electroimmunodiffusion. The electroimmunodiffusion procedure was the most rapid and sensitive method and required the least amount of reagents.