Which of the following is NOT a method used to check milk quality?

Fermentation rate measurement is not typically used as a method to assess milk quality. Instead, this method is more relevant for the evaluation of various fermentation products or processes, such as those involving dairy products like yogurt or cheese, rather than assessing the quality of milk itself.

Milk quality is primarily determined through three key methods: physical appearance examination, microbial analysis, and flavor testing.

The physical appearance examination allows for the detection of any visible defects or contamination, such as abnormal color, consistency, or presence of foreign particles. Microbial analysis is critical as it identifies the types and levels of microorganisms present in the milk, which can indicate spoilage or safety concerns. Flavor testing evaluates the taste of the milk, which can be influenced by several factors including freshness and the presence of off-flavors caused by bacterial growth or spoilage.

In summary, while fermentation rate measurement may play a role in other dairy-related processes, the other methods listed are essential in directly evaluating the quality of milk itself.