Preservation describes the extension of the shelf life of food and beverages. 
All fresh food, regardless of whether it is of animal or vegetable origin, is subject to a constant process of change from the time it is obtained. This process usually leads to a reduction in quality that can lead to complete spoilage of the food. In order to preserve food longer, the process of change must be stopped or slowed down. Many methods of preservation therefore try to remove, kill, or stop the microorganisms or processes responsible for spoilage – or at least suppress them. Apart from food preservation, knowing how to improve blood circulation in can help you eat healthily.
Common food preservation methods
Biological conservation methods
Desired microorganisms are used in biological preservation methods. Their growth and metabolism prevent the development of unwanted spoilage organisms and germs. Biological preservation methods include lactic acid fermentation and alcoholic fermentation. The alcohol produced during alcoholic fermentation has a preservative effect. For example, food can be preserved by soaking it in high-percentage alcohol at least 14 to 20 percent by volume, as the alcohol kills microorganisms.
Chemical preservation methods
In the case of chemical preservation methods, preservatives are used which are subject to the additive approval regulation. Chemical preservatives are substances that kill microorganisms in concentrations that are not or barely perceptible to the senses or at least inhibit their development. In principle, all chemical preservatives are prohibited in the production of meat, fruit juices, and dairy products. However, limited quantities of chemical preservatives are permitted for some of the foods. For example, nitrates may be used in curing meat. Nitrites inhibit the development of clostridia and thus reduce the risk of meat poisoning. Alcohol, table salt, and certain components of the smoke that are produced during smoking have antimicrobial properties but are not considered chemical preservatives.
Physical conservation methods
Many methods of preserving food are based on physical processes. Since the activity of enzymes and microorganisms is linked to the presence of water, some physical preservation methods are based on the reduction of the freely available water. For example, when drying, candying, or curing. In addition to dehydration, other important preservation methods are based on the action of heat. These include, for example, pasteurization and sterilization.