Question

Which organism is responsible for converting milk into curd?

• A. Fungi
• B. Bacteria
• C. Virus
• D. None of these

Hint:

Lactic acid produced by a microorganism curdles the milk protein.

Answer 1

The Correct Option is B

Step 1: Recall how curd forms from milk.
Curd forms when milk sugar, called lactose, is broken down and turned into lactic acid. This drop in pH causes the milk proteins to clump and thicken, which is what gives curd its texture.

Step 2: Identify the organism responsible.
This souring and thickening is carried out by lactic acid bacteria, mainly species of Lactobacillus. These bacteria feed on lactose and release lactic acid as a byproduct, which curdles the milk.

Step 3: Rule out the other options.
Fungi such as yeast are used in processes like bread making and fermenting alcohol, not in turning milk into curd. Viruses cannot carry out fermentation on their own since they need a host cell to do anything at all, and they play no role in curd formation. Since bacteria are clearly responsible, the option "None of these" does not apply.

Step 4: Final answer.
Bacteria, specifically lactic acid bacteria, are responsible for converting milk into curd.
\[ \boxed{\text{Bacteria}} \]