What is a major consequence of excessive heat treatment of milk?

Excessive heat treatment of milk can lead to a loss of flavor due to the breakdown of sensitive flavor compounds that are natural to fresh milk. When milk is subjected to high temperatures for extended periods, it can also cause the Maillard reaction, which alters the milk's taste, making it less desirable. The thermal degradation can change both the aromatic and flavor profiles, often resulting in a boiled or cooked flavor that is not appealing to consumers.

In contrast, while increased shelf life and reduction of microbes might occur due to heat treatments like pasteurization, excessive heat can further degrade the quality of the product. Higher nutritional values are generally not achieved through excessive heat treatment; in fact, some heat-sensitive vitamins may be destroyed, affecting the overall nutritional quality of the milk. Thus, loss of flavor is a significant and direct consequence of overheating milk.