Why do we preserve food?
Humans invented techniques for preserving food to prevent shortages and to be able to transport perishable foodstuffs. Such techniques slow down the decay of food triggered by microorganisms.

What are microorganisms?
Bacteria, yeasts and even moulds are living beings. Although they are invisible to the naked eye, they are omnipresent. Most are harmless, some of them can make us ill, and others, on the other hand, can enrich foodstuffs.

How do microorganisms proliferate?
Moderate temperatures are conducive to the proliferation of microorganisms, whereas high temperatures destroy them and cold hinders their growth.
The proliferation of microorganisms also depends on water being available. If water is bonded to other molecules, it is, as such, unavailable. The more water in a foodstuff is available, the more microorganisms can develop. This is the case for milk and raw meat.
Depriving most microorganisms of oxygen prevents them from multiplying. Finally, acidity also has an impact on microorganisms. They cannot proliferate and may even be destroyed in an acidic environment or when alcohol or preservatives are present.

How do we preserve food?
The main purpose of preservation techniques is to restrict or block the development of microorganisms by adapting temperature, or levels of water, oxygen or acidity. A few simple precautions are important too, such as washing your hands, using clean utensils and storing, cooking or reheating food at the appropriate temperatures.