Question

What happens when milk is left open at room temperature during summers?

Answer 1

Hint: In order to answer this question, we will explain the event when milk is left open at room temperature during summers and we will also explain why milk becomes sour in the summer season that is harmful for us.

Complete answer: When milk is left at room temperature during the summer, it undergoes an oxidation reaction and microbe development, causing it to become sour. It also begins to break, which can be seen on the top of the vessel. In terms of consumption, that milk has been rendered useless. You can use it on your hair. As soon as the milk cools to room temperature after being boiled, it should be placed in the refrigerator so that the consistency is maintained and the milk can be used for a longer period of time.
Or in other words, Lactose is converted to lactic acid when milk is left at room temperature due to a bacterial process. Lactose is fermented and transformed into lactic acid by bacteria at room temperature.
Fungi can survive pasteurisation in milk, but they can't reproduce or undergo chemical reactions at temperatures below 7 degrees Celsius. So they start reproducing and turning milk into "sour milk" at temperatures of 20–30 degrees Celsius, which can cause stomach problems, especially during the summer. That’s how milk becomes sour in summer.

Note:
When there is a lot of acid in the milk, there will be a lot of hydrogen ions, which will make the flavour sour, especially if the pH is low. When the pH is low, the structure of proteins such as casein changes, causing the milk to curdle and form clumps.