CA Cold Storage uses oxygen and carbon dioxide concentrations of about 1% to 5% for each gas in most applications. Normal room air has an O2 concentration of about 21% and CO 2 levels near 0.03%. Low O2 and high CO 2 levels slow the ripening process, stop the development of some CA Cold Storage disorders such as scald in apples, and slows the growth of decay organisms. All of these effects increase storage life of fresh produce compared with conventional refrigerated stores. These facilities are recommended for long term storage of fruits and vegetables like Apples, Pears, kiwi, cabbage etc. for up to 10 months.
CA Cold Storage are generally multiple chambers with each chamber of capacity of 50-250 MT. However, it is expected that economically viable designs of small CA Cold Storage of single chamber and storage capacity of 50 MT or so may come up in near future. In CA Cold Storage produce is stored in large bins which are stack able up to 11 high (total chamber height up to 10 m) or in PVC crates which can be stacked in mild steel pallet frames up to 4 levels high (chamber height up to 8 m). CA Cold Storage in CFB box may also be resorted to for short duration storage of fruits like strawberry. The refrigeration system is designed to maintain temperature of -1ºC with humidity of 90%-95% RH.
Recommended levels of O2 and / or CO 2 are automatically regulated, measured and corrected during the storage period. Manual regulation supported by high precision analyzer has been in use in some countries but are getting phased out. In spite of cost implication automatic regulation levels of O2 and / or CO 2 is recommended to minimize possibility of storage disorders in high value produce stored in CA Cold Storage.
In Indian context, use of Controlled Atmosphere technology has increased steadily, contributing significantly to extending the post harvest life and maintaining the quality of apples during the past few years. This trend is expected to continue as technology advances are made in this field.