Which test is used to determine if milk has been pasteurized properly?

The phosphatase test is the method used to determine if milk has been properly pasteurized. When milk undergoes pasteurization, the goal is to eliminate harmful bacteria and pathogens while extending its shelf life. The enzyme alkaline phosphatase is naturally present in raw milk, and effective pasteurization deactivates this enzyme.

In the phosphatase test, a sample of the milk is heated with a specific substrate that reacts with the enzyme. If the enzyme is still active, indicating that the milk was not pasteurized effectively, a color change will occur. Conversely, if the phosphatase is no longer active, it shows that pasteurization has been successful. This makes the phosphatase test a critical quality control measure in the dairy industry.

Understanding the effectiveness of pasteurization is key for ensuring milk safety and quality. The other tests mentioned do serve important functions in dairy quality control but are not specifically designed to assess pasteurization efficacy. For instance, the alcohol test evaluates the stability of milk against curdling when ethanol is added, the coliform test checks for contamination by indicator bacteria, and the somatic cell count test measures the health of the dairy herd and milk quality. Each of these tests has its purpose,