Question

We add a spoonful of in the warm milk
obtain curd

Answer 1

Hey, mate! I'm not really sure what is question but I can explain why we do so.

Answer:

In our everyday life, we consume Lactic Acid which is found in curd. Since it is an acid also found in our body, just like a bacteria, it multiplies in warm milk. Hence, converting the milk into curd.

Explanation:

In other words, the acid in the spoonful of curd multiplies in whatever quantity of milk, producing curd