Question

Given below are two statements:
Statement (I): The main purpose of using protected production systems for bulk starter culture preparation is to control contamination from yeast and mold.
Statement (II): Starter culture rotation would prevent the build-up of bacteriophage and thus avoid starter failure because they are virulent against one host type.

• A. Both Statement (I) and Statement (II) are true
• B. Both Statement (I) and Statement (II) are false
• C. Statement (I) is true but Statement (II) is false
• D. Statement (I) is false but Statement (II) is true

Hint:

HEPA filtration and sterile air overpressure in bulk starter tanks are designed specifically to exclude bacteriophages, which are much smaller (around 20–200 nm) than bacterial or mold cells.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Maintaining starter culture activity requires preventing microbiological contamination during bulk propagation and preventing bacteriophage build-up in the processing environment.
Detailed Explanation:
Let us evaluate both statements:
- Statement I: Bulk starter culture preparation involves growing large volumes of starter bacteria. The main purpose of using specialized, protected production vessels (such as bulk starter vessels equipped with HEPA filters and positive pressure) is to prevent contamination from bacteriophages (which can easily enter through air and destroy the starter). Contamination by yeast and mold is of secondary concern compared to the threat of phages. Thus, Statement I is false.
- Statement II: Bacteriophages are highly host-specific; they typically infect and multiply within only one host strain (or a set of closely related strains) due to the specificity of cell surface receptors. Rotating different phage-unrelated starter strains prevents the build-up of phages in the processing plant, thereby avoiding starter failure. Thus, Statement II is true.
Since Statement I is false and Statement II is true, the correct option is (D).
Final Answer:
Statement (I) is false but Statement (II) is true. Hence, the correct option is (D).