Controlled atmosphere storage is a specific storage method, commercially developed in Europe and United States in the early 1950’s, born from the need to avoid oxygen entering into contact with foodstuffs. The atmosphere’s composition is maintained constantly through the use of automatic control systems: the air inside the rooms is modified with formulae which vary according to the type of product being stored, these mixtures are checked and maintained by specific apparatus, while the temperature is maintained within a range from -0,5°C to 12°C depending on the product being stored.
The air inside the rooms is deprived of the most part of its’ oxygen and is enriched with nitrogen , CO2 or a mixture of both. The level of CO2 is kept under control and maintained at a constant level in order to avoid damage to the stored fruit as well as impeding the formation of moulds and/or bacteria , while the nitrogen , almost completely substituting O2, slows down the fruits’ respiration rate and oil deterioration preventing rancidity.
Controlled atmosphere storage is applied to horticultural products: after harvesting, the products “breathe” and produce heat, water vapour, carbon dioxide (CO2) and aromas. All of these factors cause deterioration of the produce, therefore for long and healthy storage of the products cooling is not sufficient, the oxygen levels need to be reduced and CO2 production must also be kept under control with the aim of lengthening storage time.
Controlled atmosphere combined with cooling act together to avoid deterioration of the external aspect (peel, colour) and internal ( pulp, vitamins, acids, consistency) of the produce stored inside the refrigerated storage rooms.
Nowadays controlled atmosphere storage is universally used for the storage of many products over several months, in the case of apples and pears up to 10-12 months, and this allows markets to be supplied year round.