Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : The Lactoperoxidase (LP) system in raw milk utilizes water and thiamin to generate free radicals
Reason (R) : Free radicals formed by the LP system act by damaging bacterial cell membranes and disrupting essential cellular processes, thereby inhibiting bacterial growth.
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:

The three essential components of the active LP system are:
\[ \text{Lactoperoxidase (enzyme)} + \text{Thiocyanate (SCN}^-\text{)} + \text{Hydrogen Peroxide (H}_2\text{O}_2\text{)} \]

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The Lactoperoxidase (LP) system is a natural antibacterial defense system found in raw milk, composed of three components: the enzyme lactoperoxidase, thiocyanate (\(\text{SCN}^-\)), and hydrogen peroxide (\(\text{H}_2\text{O}_2\)).

Step 2: Detailed Explanation:
- Assertion (A): The LP system catalyzes the oxidation of thiocyanate ions (\(\text{SCN}^-\)) by hydrogen peroxide (\(\text{H}_2\text{O}_2\)) to produce antimicrobial intermediate compounds (such as hypothiocyanite, \(\text{OSCN}^-\)). It does not utilize water and thiamin. Thus, Assertion (A) is false.
- Reason (R): The reactive intermediate products (including free radicals and hypothiocyanite) produced by the LP system oxidize sulfhydryl groups in bacterial proteins, damaging cell membranes and disrupting essential metabolic processes to inhibit bacterial growth. Thus, Reason (R) is true.

Step 3: Final Answer
Since Assertion (A) is false but Reason (R) is true, the correct option is (D).