Question

The conventional method (antigen - antibody cross-linking) given for detecting the presence of buffalo milk in cow milk is

• A. Somatic cell test
• B. Protein profiling
• C. Fatty acid profiling
• D. Hansa test

Hint:

The Hansa test is an immunological assay (agglutination test) developed at NDRI, India. It can detect even small admixtures (up to 1-2%) of buffalo milk in cow milk.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Adulteration of premium cow milk with cheaper buffalo milk is a common concern in the dairy industry.
Detecting this admixture requires sensitive analytical techniques that can differentiate between species-specific proteins.

Step 2: Detailed Explanation:
Let us evaluate the analytical methods for milk species detection:
- Somatic cell test: This test measures somatic cell counts to screen for mastitis, not milk species.
- Protein profiling & Fatty acid profiling: These are instrumental methods (using chromatography or electrophoresis) that require laboratory setups and are not conventional rapid screening tests.
- Hansa test: This is a classic immunological test developed in India (at the National Dairy Research Institute) to detect the adulteration of cow milk with buffalo milk.
- The test is based on antigen-antibody agglutination.
- Antiserum is produced by immunizing rabbits with buffalo milk proteins. This antiserum contains antibodies that bind specifically to buffalo milk protein antigens.
- When this specific antiserum is mixed with a milk sample containing buffalo milk, antigen-antibody cross-linking occurs, resulting in visible agglutination (clumping) of the fat globules within a few minutes.
- If the sample contains pure cow milk, no reaction occurs.
Therefore, the Hansa test is the conventional immunological method used for this purpose.

Step 3: Final Answer:
The conventional antigen-antibody method used for detecting buffalo milk in cow milk is the Hansa test.