Question

Which starter culture types among the following are usually resistant to bacteriophage attack?
(A). Single strain starters
(B). Multipile strain starters
(C). Mixed strain starters
(D). Artisanal Starters
Choose the correct answer from the options given below:

• A. (A), (B), (C), (D)
• B. (A), (B), (C)
• C. (B), (A), (D)
• D. (C), (B), (D)

Hint:

Bacteriophage resistance is driven by genetic diversity. Defined single-strain starters are highly vulnerable, whereas diverse mixed or multiple-strain cultures are robust against phage attacks.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Bacteriophages are highly host-specific viruses that infect and destroy specific strains of starter culture bacteria.

Step 2: Detailed Explanation:
Let us analyze the susceptibility of different starter systems:

• (A) Single strain starters: Contain only one defined strain of bacteria. If a phage specific to that strain enters the vat, it will infect and lyse all the cells, leading to complete fermentation failure. Thus, they are highly susceptible to phage attacks.

• (B) Multiple strain starters: Contain a defined mixture of two or more distinct, phage-unrelated strains. If one strain is attacked, the other resistant strains can continue the fermentation. (Resistant)

• (C) Mixed strain starters: Contain undefined mixtures of many different strains and species. The high genetic diversity ensures that at least some strains will be resistant to any given phage. (Resistant)

• (D) Artisanal Starters: Traditional, undefined cultures (such as back-slopping starters) that have evolved a high diversity of strains and species over time, making them naturally resistant to phage-induced failure. (Resistant)
Therefore, multiple-strain, mixed-strain, and artisanal starters are resistant to bacteriophage attacks.

Step 3: Final Answer
The starter types resistant to bacteriophage attack are (C), (B), and (D).