Cold Storage for fruits and vegetables

Introduction

Cold storage is the one widely practiced method for bulk handling of the perishables between production and marketing processing. It is one of the methods of reserving perishable commodities in fresh and whole some state for a longer period by controlling temperature and humidity with in the storage system. Maintaining adequately low temperature is critical, as otherwise it will cause chilling injury to the produce. Also, relative humidity of the storeroom should be kept as high as 80-90% for most of the perishables, below (or) above which his detrimental effect on the keeping quality of the produce.

Most fruits and vegetables have a very limited life after harvest if held at normal harvesting temperatures. Postharvest cooling rapidly removes field heat, allowing longer storage periods. Proper postharvest cooling can:

• Reduce respiratory activity and degradation by enzymes;
• Reduce internal water loss and wilting;
• Slow or inhibit the growth of decay-producing microorganisms;
• Reduce the production of the natural ripening agent, ethylene.

In addition to helping maintain quality, postharvest cooling also provides marketing flexibility by allowing the grower to sell produce at the most appropriate time. Having cooling and storage facilities makes it unnecessary to market the produce immediately after harvest. This can be an advantage to growers who supply restaurants and grocery stores or to small growers who want to assemble truckload lots for shipment. Postharvest cooling is essential to delivering produce of the highest possible quality to the consumer

Cold storage can be combined with storage in an environment with added of carbon dioxide, sulfur dioxide, etc. according to the nature of product to be preserved. The cold storage of dried/dehydrated vegetables in order to maintain vitamin C, storage temperature can be varied with storage time and can be at 0°-10°C for a storage time of more than one year, with a relative humidity of 80-95 %.

The cold storage of perishables has advanced noticeably in recent years, leading to better maintenance of organoleptic qualities, reduced spoilage, and longer shelf lives.

These advances have resulted from joint action by physiologists to determine the requirements of fruit and vegetables, and by refrigerating specialists to design and run refrigerating machines accordingly.

Care should be taken to store only, those kinds, which does not show in compatibility of storage, when storing multi produce in the same room. For example, apple can be stored with grapes, oranges, peaches, and plums and not with banana. However, with potato and cabbage slight danger of cross actions can occur. Contrary to this, grape in compatible to all other vegetables except cabbage. To resolve the incompatibility during cold storage, foodstuffs are grouped into three temperature ranges

Based on their thermal incompatibility the produce is classified into

• Most animal products (or) vegetable produce, not sensitive to cold (0-4°C)
  E.g. Apple, grape, carrot and onion
• Vegetable produce moderately sensitive to cold (4-8°C)
  E.g. Mango, orange, potato and tomato (ripened)
• Vegetable produce sensitive to cold (>8°C)
  E.g. Pineapple, banana, pumpkin and bhindi

Based on the purpose the present-day cold stores are classified into following groups:

• 1.Bulk cold stores: Generally, for storage of a single commodity which mostly operates on a seasonal basis E.g.: stores for potatoes, chilies, apples etc.
• 2.Multipurpose cold stores: It is designed for storage of variety of commodities, which operate practically, throughout the year.
• 3.Small cold stores: It is designed with pre-cooling facilities. For fresh fruits and vegetables, mainly for export-oriented items like grapes etc.
• 4.Frozen food stores: It is designed for with (or) without processing and freezing facilities for fish, meat, poultry, dairy products and processed fruits and vegetables.
• 5.Mini units /walk in cold stores: It is located at distribution center etc.
• 6.Controlled atmosphere (CA) stores: It is mainly designed for certain fruits and vegetables

Scope

• 11% of worlds total vegetable production is accounted by India alone, but India's share in global vegetable trade is only 1.7%.
• One of the key reasons for high food inflation in India is the lack of efficient supply chain for food, of which Cold chains form an integral part.
• Change in lifestyle and demand for processed or packaged food is creating the need for cold storage solutions across India.
• Subsidy by government in this Sector.