MICROWAVE PASTEURIZATION OF MILK IN A CONTINUOUS-FLOW UNIT - SHELF-LIFE OF COWS MILK

Cow's milk was pasteurized in a continuous microwave heating system at 80.1 degrees C for 15 s. The extent of the heat treatment was determi ned by measurements of undenaturated beta-lactoglobulin, alkaline phos phatase, lactoperoxidase and proteolytic activity. Shelf life of the p asteurized milk was estimated by testing total bacterial counts, exten t of proteolysis and sensory scores during 15 d of storage at 4.5+/-0. 5 degrees C. Results were compared with those obtained in the case of milk heated in a plate heat exchanger under the same conditions. Micro wave treatment provided mirk with satisfactory microbial and sensory q ualities while causing lower thermal damage than the plate heat exchan ger. Shelf life of microwave heated milk was longer than that of milk heated in the prate heat exchanger and microwaved milk received a high sensory score during 10 d of storage.