Changes in pH on heating milk. (A) Changes in pH with heating time for the 9.6% TS milk heated at 20 °C (●), 30 °C (○), 40 °C (▼), 50 °C (▽), 60 °C (■), 70 °C (□) and 80 °C (♦). (B) Changes in pH with heating time for the 28.8% TS milk heated at 20 °C (●), 30 °C (○), 40 °C (▼), 50 °C (▽), 60 °C (■), 70 °C (□) and 80 °C (♦). (C) Changes in final pH after 60-min heating at a range of temperatures for the 9.6% TS (●), 19.2% TS (○), 28.8% TS (▼) and 38.4% TS (▽) milk samples.