Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A): On Eosin Methylene Blue (EMB) agar, some lactose fermenting species of enterobacteria, such as Escherichia coli will grow into pink colonies, but Salmonella does not.
Reason (R): Members of genus Salmonella are non lactose fermenters.
In light of the above statements, choose the most appropriate answer from the options given below.

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

Hint:

To avoid confusion, always associate these classic diagnostic appearances:
- E. coli on MacConkey Agar \(\rightarrow\) Pink colonies (due to neutral red indicator).
- E. coli on EMB Agar \(\rightarrow\) Green metallic sheen on dark colonies.
- Non-lactose fermenters (Salmonella, Shigella) \(\rightarrow\) Colorless colonies on both media.

Answer 1

The Correct Option is D