Question

Bactofugation of milk is done

• A. To kill all pathogens in milk
• B. To kill almost all bacteria in milk by fumigation
• C. To remove almost all bacteria in milk by centrifugation
• D. To kill almost all spores in milk

Hint:

Bactofugation is a physical removal process (centrifugation), whereas pasteurization and sterilization are thermal inactivation (killing) processes.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Bactofugation is a physical preservation technique used in the dairy industry to reduce the microbial load of milk without applying high-temperature thermal treatments.

Step 2: Detailed Explanation:
- Mechanism: Bactofugation utilizes high-speed centrifugal separators (bactofuges) that generate intense centrifugal force.
- Principle: Bacteria and, in particular, bacterial spores have a higher density (\(1.07 \text{ to } 1.12 \text{ g/cm}^3\)) than milk plasma (\(1.03 \text{ g/cm}^3\)).
- Under high-speed centrifugation, these denser bacterial cells and spores are projected outward and separated into a heavy fraction called "bactofugate," which is then discharged.
- This process physically removes up to \(95\%\) to \(99\%\) of bacteria and their highly heat-resistant spores from the milk, rather than killing them.

Step 3: Final Answer
Bactofugation is done to physically remove bacteria and spores from milk via centrifugation.