The measurement and significance of ionic calcium in milk - A review

The measurement of ionic calcium in milk and milk products is of vital importance in understanding the role of calcium in milk. This review compares the methods of measurement including ion equilibration, murexide and ion selective electrodes. Secondly the variations in milk from individual cows and goats, and in bulk milk samples are reviewed. The third section examines the differences in ionic calcium in relation to processing: addition and removal of calcium and other salts, rennet coagulation, miscellaneous influences, filtration and evaporation and drying are all reviewed. Finally the review considers why ionic calcium measurement is not more widely measured within the diary industry and argues that it could be beneficial to do so.