Heating and Storing Milk on Dairy Farms Before Pasteurization in Milk Plants

Abstract

Fresh uncooled raw milk was heated at subpasteurization temperatures through a thin plate heat exchanger and stored in a refrigerated bulk tank at 3 + 1 C. Equal quantities of heated milk were added to the tank each day or every other day. After 7 days, the stored milk was delivered to a milk processing plant where it was pasteurized. Chemo-biological analysis of the milk before and after pasteurization indicated that the farm-heated milk maintained satisfactory quality after 7 days of storage at 3 -+ 1 C. Selected data on the stored milk were comparable to those of regular milk for bacterial counts, acid degree values, and amino acid composition. A consumer panel of 800 persons tasted pasteurized, aged, farmheated (stored) milk, and fresh milk control. About 43% of the panelists expressed no sample preference; 30.8% of the panelists preferred fresh milk.