What happens to a poured glass of milk if you leave it for a day?

If a glass of milk is left for a day at room temperature, it will turn sour. Or even curl up, turn into yogurt. There is an explanation for this process. Microorganisms and bacteria live in almost all substances. Milk is no exception. At a favorable temperature (20 – 30 degrees) bacteria begin to actively feed and multiply. They feed on lactose. The sugar it contains is processed into lactic acid. At the same time, proteins are folded. The higher the air temperature, the faster the milk souring process.