Question

Why does a milkman add a small amount of baking soda to fresh milk to shift the pH of fresh milk from 6 to slightly alkaline?

Answer 1

a) By adding a very small amount of baking soda to fresh milk, the milkman keeps the milk unspoiled for little more time than usual time.
As the pH value increases the milk turns to slightly alkaline, 
b) As baking soda is added, it turned into a base. But curd needs acidic condition to set. Hence this milk takes a long time to set as a curd.

Answer 2

Hello Sweet(y70)
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Yes ! The Milkman add small amount of baking soda in fresh milk to make the pH increase from 6 to slightly alkaline . Milkman do it because after increasing pH milkman make the milk more basic if the pH decreases the milk will be spoiled and become undrinkable . By doing so milkman maintain the pH of milk and that way milk will preserve for longer use 
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