Fast detection of bovine milk in Rocquefort cheese with phastsystem by gel isoelectric focusing and immunoblotting

.Summary - A fast procedure for the detection of bovine milk in Roquefort cheese is described. It is based on the separation by rapid isoelectric focusing on Phasteysterne apparatus of 12-caseinsfrom the milk of the 2 species. The presence of bovine milk is also confirmed by the detection in the electrophoretic pattern of a ~-casein derived peptide from bovine milk, during cheese ripening, identified by immunoblotting. By using Ihis procedure, levels of bovine milk as low as 5% were easily delecled in Roquefort cheese ripened for a period varying from 10 days to 5 months.