Why does milk go sour?
Is it so bad?
There is only one product in the world which no species of mammal can survive without. Milk. Whether it’s a baby human being, deer, kitten or elephant, the first thing they will eat in their lives is their mother’s milk.
The benefit of this product was proved in Ancient Greece. For example, Hippocrates prescribed it for patients as a cough medicine, while the renowned Russian scientist Ivan Pavlov called milk a food created by nature.
Milk is excellent for quenching the thirst, and provides the body with practically all the necessary elements required for proper growth and development. Besides its benefits, the product has a unique taste that is pleasing to both children and adults.
Despite all of its numerous beneficial properties, milk has one serious shortcoming – it goes bad very quickly. Why does it turn sour? Is this a bad thing or a good thing? How can we keep it fresh? We will try to answer these questions in this article.
To start with, let’s see what milk is and what it consists of. Milk is a nourishing, multi-component liquid which is produced by the mammary glands for feeding babies. Its composition includes:
macroelements (calcium, magnesium, fluorine, sodium, phosphorous, iodine, chlorine, sulfur etc.);
microelements (iron, copper, zinc, iodine, fluorine, silicon, chromium etc.);
proteins (albumin, globulin);
vitamins (А, D, E,K, B);
The quantity of the various elements depends on the origin of the milk.
Why does milk go sour?
As we can see from the composition, the lactic medium contains various types of bacteria. In normal form they are not dangerous for the organism, but over time (especially under the influence of accelerating factors) they start to multiply, transforming lactose into lactic acid. As a result, the acidity of the milk increases, which in its turn causes the protein to fold and liquid to separate into whey and a viscous mass.
The speed of souring is affected by:
temperature – the higher it is, the greater the souring effect;
a dirty container – the presence of water, fat, dust etc. in the milk container can double the speed of the time it takes milk to go sour.
the weather – if you put a milk jug on the window sill during a storm, in the morning you will have home-made kefir. Scientists cannot give a precise explanation of this process, but many believe that it is caused by electromagnetic impulses.
specific bacteria – specially created substances designed for a quicker and more effective change of milk into beneficial fermented milk products. They include: kefir fungi (kefir), lactic yeast (yoghurts), propionic bacteria (cottage cheese) and lactobacillus (boiled fermented milk).
By the way, you can do a very easy experiment on find the protein in your favourite milk.
How are fermented milk products beneficial (harmful)?
The benefit of fermented milk:
Easily digestible – whole milk is digested by just 32%, while kefir or boiled fermented milk is digested by 91%.
The lactose helps to improve the functioning of the digestive system.
Lactic and bifidus bacteria help the body to protect the intestine from harmful microorganisms.
The acidic medium helps to absorb calcium better.
You can make kefir yourself. Just add a spoonful of sour cream to milk, or wait for it to go sour of its own accord. Good milk will start to ferment after being kept in a warm place for just 8-12 hours. Dairy farms rigorously destroy all bacteria capable of multiplying before packaging milk in cartons. They do this to extend the shelf life of the product. This milk can be kept for a long time, but if it ferments it will acquire a bitter acidic taste, and may cause various diseases.
How can we keep milk fresh? A few little tricks.
Only pour milk into a dry, clean container (preferably glass or ceramic).
ONLY wash milk containers with cold water (hot water accelerates the fermentation process).
Keep milk away from other smells and air.
4.Keep away from light (this causes vitamins to break down).
Observe these simple rules, and milk will keep your family happy for a long time to come. There’s a good reason that people say “Drink milk and you’ll be healthy”.