Question

Match List-I with List-II
\begin{tabular{ll} List-I & List-II
(A) Starter distillate & (I) Bacteriophage
(B) Nisin & (II) Propionibacteria
(C) Calcium deficient medium & (III) Diacetyl
(D) Cobalamin & (IV) Lactococcus lactis ssp. lactis

Choose the correct answer from the options given below:

• (A) - (I), (B) - (II), (C) - (III), (D) - (IV)
• (A) - (I), (B) - (III), (C) - (II), (D) - (IV)
• (A) - (I), (B) - (II), (C) - (IV), (D) - (III)
• (A) - (III), (B) - (IV), (C) - (I), (D) - (II)

Hint:

Nisin is always associated with Lactococcus lactis ssp. lactis (B - IV).
Bacteriophages require calcium for host adsorption, meaning calcium-deficient media are used to inhibit them (C - I).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
This matching question connects biological processes, protective mediums, and metabolic byproducts with their respective lactic acid bacteria and related dairy applications.

Step 2: Detailed Explanation:
Let us correlate the items in List-I with those in List-II:
- (A) Starter distillate: This is a concentrated flavor extract obtained by steam distillation of starter cultures, containing very high concentrations of diacetyl (the key butter aroma compound).
Thus, (A) matches with (III).
- (B) Nisin: This is a widely used food-grade bacteriocin produced naturally by certain strains of Lactococcus lactis ssp. lactis.
Thus, (B) matches with (IV).
- (C) Calcium deficient medium (CDM): Dairy bacteriophages require calcium (\( \text{Ca}^{2+} \)) ions for adsorption onto the host bacterial cell wall.
Growing starter cultures in a calcium-deficient medium prevents phage replication and protects the starter from phage attack.
Thus, (C) matches with (I).
- (D) Cobalamin (Vitamin B12): This vitamin is synthesized in significant quantities by Propionibacterium species (such as P. freudenreichii) during swiss-cheese fermentation.
Thus, (D) matches with (II).
This gives us the match: (A)-(III), (B)-(IV), (C)-(I), (D)-(II).

Step 3: Final Answer:
The correct matching sequence corresponds to option 4.