Question

Why does curd become sour if it is not transferred to a cool place after it is made?

Answer 1

curd is formed out of milk by the division of bacteria lactobacillius .when small amount of curd is added to warm milk, the bacteria in the milk divides to convert the rest of the milk into curd. if the curd is not transferred to a cool place it becomes sour because the bacteria divides continously and produce latic acid . this makes the curd sour.
                                                     
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