Bacteria which converts milk into curd is

Options

A. Lactobacillus
B. Streptococcus
C. Closteridium
D. Spirillium

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the specific type of bacteria that converts milk into curd.

2. **Identifying the Process**: The conversion of milk into curd involves the fermentation of lactose (milk sugar) by bacteria.

3. **Recognizing Key Bacteria**: The primary bacteria responsible for this fermentation process is Lactobacillus.

4. **Explaining the Mechanism**: Lactobacillus bacteria act on lactose and ferment it into lactic acid. This lactic acid decreases the pH of the milk, causing the proteins in the milk to coagulate, which results in the formation of curd.

5. **Eliminating Other Options**:
- **Streptococcus**: While it is a bacteria, it is not primarily known for curd formation but for producing streptokinase.
- **Clostridium butylicum**: This bacteria produces butyric acid and is not involved in curd formation.
- **Spirulum**: This refers to the shape of certain bacteria and is not a specific type involved in curd formation.

6. **Final Answer**: Therefore, the bacteria that converts milk into curd is **Lactobacillus**.

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