EFFECT OF SOMATIC-CELL COUNT AND STAGE OF LACTATION ON THE QUALITY AND STORAGE LIFE OF ULTRA-HIGH TEMPERATURE MILK

The effects of bulk milk cell count (BMCC) and stage of lactation on t he quality and storage characteristics of UHT milk were investigated. The UHT milk was manufactured in a pilot plant using milk of low BMCC from early and late lactation, and milk of high BMCC from early and la te lactation. Upon storage at 20 degrees C, early lactation UHT milk g elled far ahead of late lactation milk. Within each stage of lactation , high BMCC milk. tended to gel first. Few differences in the organole ptic properties of the UHT milks mere observed. It was apparent that t he onset of age gelation may not always be related directly to the lev el of proteolysis, and that other factors influencing milk. compositio n and the reactions between milk components may play more important ro les. At a particular stage of lactation, proteolysis induced by mastit is may hasten the onset of gelation.