COMPOSITION PROPERTIES, PHYSICOCHEMICAL CHARACTERISTICS AND SHELF LIFE OF WHOLE MILK AFTER THERMAL AND THERMO-SONICATION TREATMENTS

Raw whole milk (RM) was pasteurized with heat-pasteurized milk (TT) and thermo-sonication (US) treatments. Batch pasteurization was used for TT and 36, 72, 108 and 120 mm of the ultrasound wave intensity (24 kHz, 400 W); in addition, the heat conditions were applied together for US. Apparent protein content of US milk decreased; butter fat content was increased by US treatment. Proximal analysis showed the presence of added water in US milk and a decrease of nonfat solids, whereas pH was decreased for US milk, lactic acid was increased and density was decreased from RM to US; also, the color of US milk was whiter. The tested parameters for the TT samples were often intermediate between RM and US samples. Statistical analysis showed a significant difference (P < 0.05) among all treatments. After 16 days, US samples (4C) did not show mesophilic growth higher than 2 log; pH, acidity and color remained constant.