Question

When milk is heated at \[62^\circ C\] for \[30\] minutes and then cooled, the process is called:
A.Sterilization
B.Pasteurization
C.Nitrification
D.Freezing

Answer 1

Hint: When the milk is heated, the evaporation of water will take place and the concentration of other elements will be increased. Once the temperature reaches about\[150^\circ C\], the proteins – casein and whey start to coagulate. And this will prevent the evaporation and always the surface moist. The water vapours present in the milk is lighter than all other particles or ingredients. Hence, the surface will be covered with a thin layer of cream.

Complete answer:
The sterilization is the process which is used to deactivate or remove all forms of life of a particular microorganisms like bacteria, fungi, spores etc. Hence, the option (A) is incorrect.
When milk is heated at \[62^\circ C\] for \[30\] minutes and then cooled, this process is known as pasteurization. This is a method of sterilization. And this process was established by Louis Pasteur. Here, both non – packaged and packaged food items are heated for \[30\] minutes at\[62^\circ C\]and it cools. By this process, we can eliminate the pathogens present in the food and the shelf – life of food will be extended. The pasteurization process frees the food items from the vegetative types of all the pathogenic bacteria. Therefore, the correct answer is pasteurization. Hence, option (B) is correct.
The nitrification process is the conversion of ammonia to nitrites and nitrates by oxidation method. And the given process is not nitrification. Hence, the option (C) is incorrect.
The freezing method is a phase transition of liquid phase to solid phase and the given process is not freezing. Hence, the option (D) is incorrect.

Hence, option (B) is correct.

Note:
We need to remember that the pasteurization process will reduce the chances of food poisoning. Here, the partial sterilization product makes it safe for improving their quality by eliminating pathogens and the shelf life of food will be increased. Here the foods like packaged and non – packaged items are treated with mild heat. By this process, it kills the harmful pathogens and microorganisms.