Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Abnormal milk from infected udder can be detected by California Mastitis Test (CMT)
Reason (R) : Milk from infected udder contain more amount of catalase enzyme
In light of the above statements, choose the correct answer from the options given below.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A)
• B. Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
• C. (A) is true but (R) is false
• D. (A) is false but (R) is true

Hint:

To verify Assertion-Reason questions, connect them with "because":
"CMT detects mastitis BECAUSE mastitic milk has more catalase." This statement is incorrect because CMT works via DNA gelation, not through catalase activity. Thus, both are true but the reason is not the correct explanation.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Mastitis is an inflammatory condition of the mammary gland (udder) in dairy animals, usually caused by bacterial infections.
This inflammation triggers a defense response, resulting in a significant increase in somatic cells (primarily white blood cells/leukocytes) and altered enzymatic profiles in milk.

Step 2: Detailed Explanation:
Let us evaluate both statements:
- Assertion (A): The California Mastitis Test (CMT) is a rapid diagnostic tool used at the cow-side to detect subclinical mastitis. The CMT reagent (an anionic surfactant like sodium lauryl sulfate) reacts with the DNA of somatic cells present in abnormal milk to form a distinct gel or precipitate. Because mastitic milk has a high somatic cell count, this gel formation confirms infection. Thus, the Assertion (A) is true.
- Reason (R): Mastitic milk containing high concentrations of polymorphonuclear leukocytes (leukocytes contain rich stores of catalase) shows elevated catalase activity. Catalase breaks down hydrogen peroxide to release oxygen gas:
\[ 2\text{H}_2\text{O}_2 \rightarrow 2\text{H}_2\text{O} + \text{O}_2(g) \]
The catalase test can also be used as an indicator of mastitis. Thus, the Reason (R) is true.
- Analysis of the Link: The CMT detects mastitis through a chemical reaction between the surfactant reagent and somatic cell DNA, which causes cell lysis and gelation. It does not measure or rely on catalase enzyme activity.
- Therefore, while both statements are true, the Reason (R) is not the correct chemical or physical explanation of how the CMT functions.

Step 3: Final Answer:
Both (A) and (R) are true, but (R) is not the correct explanation of (A).