How does souring of milk occur ?

How does rusting of iron occur ?

Milk turns sour at 40^(@)C three times as faster as 0^(@)C . Hence E_(a) in cal of process of turning of milk sour is :

Milk turns sour at 40^(@)C three times as faster as 0^(@)C . Hence E_(a) in cal of process of turning of milk sour is :

The bacterium Lactobacillus lectis that causes souring of milk is :

The bacterium Lactobacillus lectis that causes souring of milk is :