Come si conserva il cibo? | eatparade
All preservation methods are meant both to destroy microorganisms or to slow down the development of both inactivate enzymes that modify food. Physical methods include heating and cooling, water removal, the use of ionizing radiation (also criticised technique), the use of controlled atmospheres (e.g. coffee powder “under vacuum” or “below” nitrogen, the sodas).
Chemical methods, the oldest, are based primarily on the addition to food of substances (salt, sugar, vinegar, olive oil) in high doses or synthetic substances (chemical additives: preservatives, antioxidants, antimicrobials). For example, sugar (sucrose) and salt (sodium chloride) subtract the water making it unusable by microorganisms while the oil protects against oxidation. Chemical additives, much discussed periodically, have different effects depending on the chemical structure (sometimes only aesthetic, as in the case of colouring agents); their usage and their dosages are strictly regulated.
Biological methods are blocking the development of harmful microorganisms, thereby facilitating the development of beneficial microorganisms in the case of yogurt.
Food storage is a very old tradition, as evidenced by the practice of smoking and salting meat and fish. For example, in the Renaissance there was also used to spice the meat thoroughly, a bit to lengthen its shelf life and some to hide the bad taste produced by their decay.
The scientific justification of these treatments are recent and are due to advances in microbiology from one side and on the evolution of industrial technologies from each other.
The different preservation methods were then joined the industrial processes that have led to food or semi-finished products (foods, pre-cooked, etc.). Also evolved in parallel legislation and controls, increasing safety; for example, the obligation to enter on the packaged food expiration date and label with nutritional content.
