Rapid Method for the Determination of Casein in Milk by the Dye Binding Method and for the Detection of Mastitis

The casein is removed by buffering a 1:10 dilution of skimmilk at pH 4.6. All operations are performed in a single 50-ml centrifuge tube. After centrifugation, the wet casein precipitate is redispersed and treated with a dye reagent. A standard curve relating absorbanee of the remaining free dye to the casein percentage in the original milk is prepared, using reconstituted low-heat, nonfat milk powder of known casein content.