Question

Why does the milk spoil more easily in summer than in winter when it is left outside?

Answer 1

Hint: The microorganisms which are responsible for spoiling the milk works on the specific environment and temperature. The process of spoiling milk is known as curding or the settling of the milk.

Complete step by step answer:
1:- The sugar present in the milk is known as lactose (glucose) which can be easily converted into lactic acid and make the milk sour and convert it into curd.
2:- The bacteria which is responsible for the conversion of the milk to curd is Lactobacillus lacti which works or activated on high temperature, at low temperature the working efficiency of Lactobacillus is very low as they went in the dormant stage at low temperature.
3:- When they get the appropriate temperature that is suitable for the rapid growth they grow fast and increase their number for rapid fermentation of the milk and convert it into curd.
4:- The temperature is directly proportional to the time in which the reaction takes place, if the temperature is increased by 10-degree celsius then the amount of product will increase to double.
5:- So, in summer the temperature is higher than that of the winter so the bacteria Lactobacillus function more vigorously to convert the lactose into lactic acid and spoil the milk and convert it into the curd which has a sour taste. And this whole process is known as fermentation of the milk.

Note: Fermentation of milk is helpful for obtaining different milk products like paneer, curd
which have high nutritional value. Fermentation is an anaerobic process that is carried out in the absence of oxygen.