Why food get spoiled?
"I spent a lot of experiments. And now firmly convinced: beer, wine and milk spoil invisible beings ≈ germs .. . they cause destructive process that leads to damage of products, "said Society of Naturalists September 3, 1857 while still a little-known French scientist Louis Pasteur.
Years passed before a special science has helped to clarify the reasons for microbiology of food spoilage. The culprits were basically three groups of microorganisms ≈ bacteria, mold and yeast. To our misfortune, they prefer to eat the same foods that people consume. In this ungrateful parasite is not so much eaten as food decompose, releasing a variety of inedible substances (acids, gases, etc.), whose presence is a sign of spoilage. But as it turned out, not only of food micro-organisms are alive. In order to be able to eat and reproduce, they, like humans, a number of important conditions: optimum temperature, sufficient moisture content, the absence of antibiotic substances in the product. Different microorganisms and individual flavors: one for respiration requires oxygen, while others prosper as a time when its complete absence.
Knowing the weaknesses of our enemies, we can actively deal with them. Thus, the use of low temperature for preservation of food inhibits activity of bacteria and other microorganisms. In addition, the cold inhibits enzyme systems of the products. Without the cold we were not able to keep many food products. It is important to note that the effect of cold denaturation provides the least food, which distinguishes this method from all others.
Decreases sharply in the products of vital activity of microorganisms during their dehydration. Drying of fruits, vegetables, milk, meat, fish significantly increases their safety.
Vital functions of microbes is the main but not the sole cause of food spoilage.
Insects, mites and rodents are also not miss the opportunity to become our table companions, leaving traces in food feast-dung. Often the cause of food spoilage and is our own carelessness, resulting in products contaminated with a variety of foreign substances ≈ solid (soil, dust, etc.), liquid and gaseous (adsorption of odors). Products may lose their taste, appearance and nutritional properties from the effects of certain physical and chemical factors such as light, oxygen, air, excessive moisture or dryness, and as a result of activation are in the products themselves enzymes.
Fats, such as during prolonged storage in the light go rancid, even in sterile conditions and in the cold. This process, once begun, is on the rise. That is why the storage of fat is needed darkness. This applies to foods that contain lots of fat, halvah, chocolate, mayonnaise.
Vegetables and fruits in light overripe and spoil faster. But it's not just that. In potatoes, for example, the light produced is much more harmful to our body glycoalkaloid solanine, which is rapidly accumulating on the surface of the tuber Therefore, when using a potato in the diet is necessary to remove the peel with a thick layer of greenish areas, especially where there are germs, as they primarily accumulate solanine.
Most other reasons are hiding from the daylight beer. At the light, especially in the sun, the beer started to go complex photochemical reactions, leading to a particular vice of taste, which is called the "sunshine flavor."
Excessive moisture activates the enzymes own products affect the microorganisms, as well as insect pests. For example, in the damp moldy bread. Onions and garlic are using their own phytoncids ought to protect themselves from damage when wet rot quite easily affected. Even refined sugar, which contains no microbes or enzymes, moisture gradually turns yellow: it accelerates the decomposition of the moisture in the sucrose mono sugar.
But on the other hand, the same bread in a dry place to quickly get stale.
Vegetables in the dry air lose moisture and become sluggish, ugly.
Insect pests in dry croup worse off than in the wet. Therefore reasonable to dry before storing flour, grits, salt, dried fruit, pasta, etc.
For most products, the optimal relative humidity is 75%. It's quite dry.
Thus, it becomes apparent ≈ prevent spoilage of products can be comrade, if you eliminate all the causes that produce it.