Gee! You just bought a bottle of homemade milk yesterday, put it in the fridge, and this evening, wanting to enjoy a warm drink with chocolate chip cookies, you came across the fact that the purchase impudently turned sour. Why did it happen what to do about it?
Why does milk spoil quickly?
Milk contains some bacteria. They are classified as normal microflora, and they are the main reason why milk turns sour. However, in this case, everything is a little more complicated than “it just turned sour because of the bacteria.”
lactic acid fermentation
It is also called “useful”. Its main difference and condition of usefulness is the type of bacteria. Lactic acid fermentation is caused by:
- lactic acid bacteria;
- propionic acid bacteria;
- kefir fungi;
- milk yeast.
It is thanks to them that milk turns sour normally from it, then in a natural way you can cook sour cream, kefir, cottage cheese or cheese. Some types of bacteria are specially added to milk in order to obtain delicious fermented milk products.
Butyric and unwanted fermentation
But there is unwanted fermentation, tasteless. It occurs due to butyric acid bacteria, which also cause fermentation, but the milk acquires a bitter rather than sour taste, it smells unpleasant. This usually happens with pasteurized and sterilized milk, with cheeses: they tolerate the boiling point, and therefore, when lactic acid bacteria die during the heat treatment, butyric bacteria remain and begin their work.
And milk can also turn sour due to putrefactive bacteria that enter it due to insufficiently good conditions of detention, as well as due to contamination. They cannot die during the pasteurization process, and therefore quite often the milk from the package spoils and begins to stink unbearably.
From which the conclusion follows: if the packaged milk is sour, everything is already over with it and all that remains is to pour it into the toilet.
How quickly does milk turn sour?
Homemade milk, not pasteurized and unsterilized, turns sour at room temperature 12-24 hours after milking. But it happens that homemade milk does not turn sour. This is because the cow is in ketosis. Such milk is very harmful, it almost does not ferment, and the cream has a very pronounced bitter taste.
How to prolong the life of milk?
If you don’t feel like drinking all your milk at once, but want to enjoy it a little more, try these great ways.
Putting the milk in the refrigerator is, of course, not bad, but you can also pour the milk into clean plastic bottles of 0.5 liters and then put it in the freezer. Frozen milk will keep much longer than just standing in the refrigerator. Before starting, you can boil it if you plan to store it longer.
You can also make small portions of milk for drinks. To do this, arm yourself with an ice mold, pour milk into the cells and put it in the freezer. When it freezes, transfer the milk ice cubes to a bag, and then back to the freezer. You can add it to tea and coffee in the morning, it will be delicious for the summer – that’s it.
But it’s important to know! Repeated freezing of milk is unacceptable, otherwise it will deteriorate!
Frozen milk can be stored for up to 6 months.
The best way to prolong the life of homemade milk is to boil it. This is a simple and fast method, which is called pasteurization. Pasteurized milk will keep for 3 to 7 days in the refrigerator. But it is important not to expose it to direct sunlight and not to forget it on the table.
Another great way to boil milk and prevent it from curdling is to add a tablespoon of sugar for every liter. So it will be stored for a long time and will not curl up when boiled.
However, you cannot make yogurt from boiled milk.
Do you have your own ways? Tell us about it in the comments!
The opinion of the editors may not coincide with the opinion of the author of the article.