Simply, fermentation happens.
Milk contains bacteria. When the milk is not refrigerated, the bacteria are very happy and their populations grow. The metabolism of the bacteria lowers the pH of the milk, thus souring it. This will eventually happen to fresh milk that is refrigerated, too. The cold only slows the growth and does not stop it.
It's probably from something that is or was spoiled. I think it's also because something could have spilled that was spoiled and the smell stayed with it. To get rid of it try using Baking Soda.
Because the bacteria that cause souring continue to grow, but they grow at a slower rate in the refrigerator as compared to their growth rate at higher temperatures. Although pasteurization removes pathogens, other viable microbes will remain though at reduced populations.
When milk sours it is a chemical change. It is caused by lactic acid which converts the milk and makes it become sour.
Milk contains bacteria. Bacteria reproduces. When bacteria reproduces it lowers the pH of milk. When the pH of milk is lowered, Milk tastes sour. Bacteria reproduces faster at room temperature than it does at cold temperatures. So. Your milk will last longer in a refrigerator.
This is a chemical change.
The word 'sour' is a verb (sour, sours, souring, soured), an adjective (sour, more sour, most sour), and a noun (sour, sours). Example uses: Verb: Your milk will sour more readily if you keep it in the door of the refrigerator. Adjective: The sour cherries make excellent muffins. Noun: I'll have a whiskey sour please.
No it is a chemical change because you change it back to normal.
The animal, I assume you are thanking about, has been a sours of milk for the people living in North West china. There mead can also be rich sours of nutrias. And lets not forget they can be as soft as a teddy bear.
yes because it is a different substance than before :)
No, the hot milk should NOT spoiled if you keep in refrigerator.
The population of Sours is 1,774.
You to store it in the refrigerator .
No you can not
It's a chemical change. The smell is the giveaway; a smell that wasn't there before is often an indicator of a chemical change. Also, the rate at which the milk sours can be changed by heat. For example, milk in the refrigerator is actually undergoing this souring reaction at all times, but the lower temperature inside the refrigerator slows it down so that it takes many days. But if you leave it outside the refrigerator, it will sour much more quickly - in a matter of hours. An increase in heat, therefore, quickens the reaction rate. This would not be the case in a physical change.