Which type of food would have lactic acid bacteria? Discuss their useful application.

Explanation

### Step-by-Step Solution:

1. **Identify the Food Containing Lactic Acid Bacteria**:
- Lactic acid bacteria (LAB) are commonly found in fermented foods. One of the most well-known examples is **curd** (yogurt). Other foods that contain LAB include **sour cream**, **buttermilk**, **kimchi**, **sauerkraut**, and various types of **cheese**.

2. **Understanding the Role of Lactic Acid Bacteria**:
- The primary species of lactic acid bacteria is **Lactobacillus**. These bacteria play a crucial role in the fermentation process. They utilize **lactose**, which is a sugar found in milk, and convert it into **lactic acid**. This acidification helps in preserving the food and enhancing its flavor.

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