Why does curd turns sour faster in summer than winter ??

 I like to drink curd instead of having rice with it.

But yesterday, curd was so much sour that I could not drink it.

When I complained , my mother asked me to have the sour curd mixing with rice. She added little milk also to the curd rice.

Now the same sour curd has become eatable  !!!

Curd turns sour even in winters.  But it turns sour quickly during summers.

WHY    ???

High temperatures accelerate the activity and growth of Lectobacilus bacteria.

These bacteria converts the natural sugar in milk into lactic acid. This process is necessary to set the curd.

But heat acts as an accelerator, causing the bacteria to multiply rapidly and produce acid much faster than winters.

Once the curd is set, fermentation does not stop there  !!!

The bacteria continues to produce acid, quickly pushing the taste from mildly tangy to sharply sour.

These bacteria thrive best in temperature between 30 to 45 degree Celsius which is common during summer.

That's why curd turns sour quickly in summers  !!!