Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A): Yogurt contains mixed lactic acid culture containing Lactobacillus bulgaricus and Streptococcus thermophilus
Reason (R): Whey is the by-product in the manufacture of butter

• A. Both (A) and (R) are correct and (R) is the correct explation of (A).
• B. Both (A) and (R) are correct but (R) is NOT the correct explation of (A).
• C. (A) is correct but (R) is not correct.
• D. (A) is not correct but (R) is correct.

Hint:

Remember these common dairy processing by-products: 1. Butter manufacture $\rightarrow$ Buttermilk 2. Cheese/Casein manufacture $\rightarrow$ Whey This distinction helps prevent common errors in dairy technology questions.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
This question evaluates two dairy technology concepts: the microbiology of fermented milk (yogurt) and the processing by-products of dairy manufacturing.

Step 2: Detailed Explation:
Let us alyze both statements independently:
- Assertion (A): Yogurt is produced by fermenting milk with a symbiotic starter culture containing two specific lactic acid bacteria: *Lactobacillus delbrueckii subsp. bulgaricus* (formerly *Lactobacillus bulgaricus*) and *Streptococcus thermophilus*.
These two species grow in a mutually beneficial relationship, producing lactic acid, acetaldehyde, and diacetyl, which give yogurt its characteristic texture, acidity, and flavor.
Thus, Assertion (A) is true.
- Reason (R): During dairy manufacturing, different processes produce distinct by-products:
- The manufacture of cheese, casein, or Greek yogurt separates the curd from the liquid whey.
Therefore, whey is the liquid by-product of cheese or casein manufacture.
- The manufacture of butter by churning cream separates the butter grains from the liquid buttermilk.
Therefore, buttermilk, not whey, is the direct by-product of butter manufacture.
Thus, Reason (R) is incorrect.

Step 3: Fil Answer:
The Assertion is correct, but the Reason is incorrect because whey is a by-product of cheese manufacture, not butter.
Hence, the correct option is (C).