Heat Coagulation of Evaporated Milk as Affected by Mixing Different Grades of Raw Milk

Summary When small amounts of poor milk were mixed with larger batches of good quality milk an evaporated product of uncertain heat stability was produced. The change in heat stability which was observed as a result of mixing quality, of adding lactic acid, or of aging the milk is ascribed to the accompanying change in pH. It is again suggested that for every milk there is an optimum pH, the attainment of which will result in maximum heat stability for the system involved. Identical results in terms of heat coagulation may be obtained by mixing milks of different quality or by aging a single sample.