1. Different sizes of Cans
It is a food preservation technique widely used today, and useful for practically any kind of food. The food is sealed in its container after vacuum and heated. Any organism present is eliminated by this procedure, and others can not arrive because the food is isolated by sealing the can. The entire process, which includes the filling and sealing of cans or containers, is performed automatically in modern industries.
The microorganisms and the enzymes need a certain degree of temperature to alter the food, but an excess of temperature destroys them. That is why heat sterilization is used to preserve food, especially canned foods. The closed and hermetically closed cans are subjected to high temperatures (between 100º and 130º C.) for a certain time. Once the cans are sterilized, and while they do not open and deteriorate, the products in them will remain unchanged for a long time. For this reason it is useless to store canned food in a refrigerator before opening it.
Bottling is generally used for fruits and vegetables. The process is similar to canning, but the food is placed in bottles instead of cans.
2.Drying or dehydrated
This is one of the oldest methods used by humans to preserve food. The method is based on the fact that microorganisms that contaminate food can not grow in dry foods. Traditionally, meats, fruits, vegetables, etc., were placed in sunlight to evaporate the water they had; in this way, it was achieved that it lasted much longer than if they were kept without that treatment.Currently, dehydration is an industrial process, in itself it consists of removing all the water from a food to prevent bacteria from reproducing. It can be done through the methodical, progressive and continuous application of heat, or by lyophilization.
3.Adding salt or Salado
This method of food preservation is used since ancient times. Meats and fish can be treated with cooking salt, which dehydrates them and prevents the attack of germs, acting as an antiseptic protecting food.
Smoked is another method that has been used since ancient times; smoking preserves food thanks to the antimicrobial effect of wood smoke, dehydration, the destruction of germs and enzymes by heating the food during the process.1 It mainly applies to meats, fish and some cheeses.