Question

during summer season why milkman add some baking for keeo milk fresh

Answer 1

he does that to prevent it into turning milk into curd as milk has some amount of latic acid into it which helps in formation of curd . So when he adds baking soda the milk slides up [ pH value ] towards neutral preventing from turning into curd .

I hope this would help you

Answer 2

to prevent the curd turning to milk