**Question:** All of the following statements about Lambda phage are true, EXCEPT:

A. Lambda phage is an example of a bacteriophage, a virus that infects bacteria.
B. Lambda phage can form a stable lysogeny with Escherichia coli (E. coli) bacteria, where it integrates its DNA into the host genome and remains dormant.
C. Lambda phage has a double-stranded DNA genome and is used in genetics research to study bacterial genetics.
D. Lambda phage is used as a common food additive in processed meats.

**Correct Answer:** D. Lambda phage is used as a common food additive in processed meats.

**Core Concept:** Lambda phage is a well-studied bacteriophage, or virus, that infects bacteria, specifically the Escherichia coli (E. coli) strain, MG1655. It can form a lysogenic cycle, where it integrates its DNA into the host genome and remains dormant. The lambda phage has a double-stranded DNA genome and is widely used in genetics research to study bacterial genetics.

**Why the Correct Answer is Right:** Lambda phage is not commonly used as a food additive. It is a biologic agent, not a food preservative or enhancer. Instead, it is used in research to study bacterial genetics.

**Why Each Wrong Option is Incorrect:**

A. While correct that Lambda phage is a bacteriophage, this option is incorrect because it only mentions the bacteriophage without referencing its role in bacterial genetics research.
B. This statement is correct, as it explains that Lambda phage can form a lysogenic cycle with E. coli bacteria, allowing it to integrate its DNA into the host genome and remain dormant.
C. This statement is also correct, as Lambda phage has a double-stranded DNA genome, which is essential for its use in bacterial genetics research.
D. This option is incorrect because Lambda phage is not used as a food additive. Its primary purpose is in genetic research, not food preservation or enhancement.

**Clinical Pearls:** Lambda phage is a valuable tool for studying bacterial genetics, particularly in E. coli. However, its use as a food additive in processed meats is not accurate.