Which process broke the cycle of transmission and eliminated the spread of bovine tuberculosis in people in the United States?

• A. Homogenization
• B. Fermentation
• C. Centrifugation
• D. Pasteurization

Answer: (D)

Pasteurization is a heat treatment that inactivates harmful organisms in milk, preventing them from being transmitted to people. Bovine tuberculosis is caused by Mycobacterium bovis, which can be present in the milk of infected cattle; heating milk to a standard pasteurization level kills these bacteria, so drinking milk no longer spreads the disease. This break in the dairy transmission route dramatically reduced bovine TB in humans in the United States. The other options don’t reliably kill pathogens in milk—homogenization only changes fat distribution, fermentation is a metabolic process that may alter acidity or alcohol content but doesn’t ensure pathogen safety, and centrifugation separates components without eliminating microbes.