A method is provided for obtaining .beta.-casein from skim milk. Purification of .beta.-casein from milk is achieved through a process of microfiltration using cross-flow polymeric microfiltration membranes. Cooling of the milk prior to microfiltration results in improved separation of .beta.-casein from the other milk serum proteins. Further filtration and demineralization of the microfiltered permeate results in enrichment of the fraction containing soluble .beta.-casein. An integrated scheme that allows a dairy plant to continuously separate and purify .beta.-casein is provided. Also provided is a method for obtaining cheese with improved meltability and reduced bitterness.