Which test indicates pasteurization effectiveness by measuring residual enzyme activity?

• A. Coliforms (indicates contamination)
• B. Antibiotic (allergies/sensitivity)
• C. Phospatase (effective pasteurization)
• D. Bacterial limits (quality/safety testing)

Answer: (C)

Validation of pasteurization relies on checking residual enzyme activity. Alkaline phosphatase is a heat-stable enzyme present in milk, and properly pasteurized milk should inactivate it. A test for any remaining phosphatase activity acts as a direct indicator of whether the pasteurization step reached the required temperature and time. If no phosphatase activity is detected, pasteurization was effective; if activity is present, the heat treatment may have been insufficient and corrective action is needed. Other tests serve different purposes: coliform testing looks for contamination after pasteurization, not the effectiveness of the heat process; antibiotic tests assess sensitivities, which aren’t related to pasteurization; and bacterial limits gauge overall quality and safety but don’t specifically confirm pasteurization success.