Method for extracting a protein from milk

A process for the extraction of a protein present in milk comprising:

• a) skimming and defatting milk with a glass filter having a positive zeta potential to yield a skimmed fraction comprising said protein;
• b) binding said protein in said skimmed fraction on a support comprising a ligand;
• and
• c) eluting said protein.

A process for the extraction of a protein present in milk comprising:

• a) transferring a plasmid comprising a promoter and a gene for a protein into an embryo of a non-human mammal;
• b) introducing said embryo into a female mammal of the same species that will give birth to a transgenic mammal with said gene;
• c) inducing lactation of said transgenic mammal to generate milk comprising said protein;
• d) skimming and defatting said milk with a glass filter having a positive zeta potential to generate skimmed milk comprising said protein;
• e) transferring said skimmed milk to a chromatographic support comprising a ligand that is simultaneously hydrophobic and ionic;
• and
• f) eluting said protein from said chromatographic support.