In countries with a temperate climate, much of the production of fruit and vegetables is confined to relatively short growing periods. So, cold storage for vegetables and other fresh products is essential to supply the population after the harvest season.
In tropical countries, the production period can be extended, but even so, storage is always necessary to prolong the supply to the consumer. As consumer purchasing power improves, the reasons for warehousing may shift from traditional ones to trying to meet their demands instead.
Their demands are likely to include improvements in quality and availability, and as pressure increases, improvements in warehousing techniques will be demanded.
Currently, most root crops and some fruits and vegetables are stored for periods of up to twelve months as part of the normal marketing chain and all types of products are sometimes stored for a few days or weeks:
– Because there is no immediate buyer.
– Because there is no availability of transportation or other essential facilities.
– To extend the marketing period and increase the sales volume.
– To wait for a rise in prices.
There are different forms of storage:
There are different types of cold storage for vegetables. The choice of which will depend on their cost and applicability. However, before thinking about storing fresh produce, other factors need to be taken into consideration.
The maximum shelf life of a harvested product depends on its production history, quality, and maturity at harvest. The actual storage life that can be achieved in practice can be very different, depending on the harvesting and handling procedures and the storage environment.
Not all fresh products are suitable for storage and some may require specific prior pretreatments such as “curing” or “waxing”. Some characteristics of the structure or supply of the market can create negative conditions by which stored products will compete at a disadvantage with freshly harvested products. Encompassing all these interactions are the economics of storage.
Cold storage for vegetables drives up the cost of the product, and the more sophisticated it is, the higher the additional cost. Normally, it is not worth storing a fresh product if the price increase that is obtained after the storage is not greater than the costs of the same, plus a profit in the operation.
Sometimes, it may be acceptable not to win in the cost/return ratio if it means that in the long run, the volume of product sold is greater or if the storage facilities are used more efficiently.
In certain marketing processes, pro-cooling and/or storage of the product is a common requirement and its cost is assumed to be an accepted part of the production and marketing strategy.
When warehousing is successful, the price increase of the product can be predicted using information from previous seasons, although it is very difficult for this retrospective information to be accurate. Storage costs are difficult to assess accurately, for which the following should be taken into account:
– Operational costs: Cost of labor, utilities, and administrative costs.
– The fixed costs: They include the financing and construction costs of the warehouse amortized in a reasonable period, the rental expenses, and the general costs.
– The financing: The financing cost of the harvest while it is stored, either by the person who has stored the product or by other financial entities. In any case, each day of storage means adding a cost to the product, other than direct costs.
Basic pre-treatments before storage and/or marketing:
For Cold storage for vegetables,certain pro-treatments must be performed before storage and/or marketing of any fresh produce, although several “special” treatments for specific crops are described below.
All pebbles, dirt particles, and plant debris must be removed before storage, especially if the product is to be stored in bulk. The pebbles damage the product and the particles of soil and plant debris compact it and restrict ventilation, giving rise to areas where heat accumulates, being also vehicles for pathogenic germs that damage the product.
Before the advent of refrigeration, ventilated cold storage for vegetables was the only means available to store fresh produce. Today, it is still widely used around the world for a variety of crops it is still the method of choice for sweet potatoes.
Ventilated storage in ambient air storage in which controlled ventilation is used to cool the product and maintain low temperatures. It requires a much lower capital investment and operating costs than refrigerated storage and is perfectly suited for some crops and conditions where:
- Production is stored for local use.
- Products to be stored have a relatively long shelf life, such as root vegetables, white cabbage, squash, pears, and apples.
- Regular inspection is possible to eliminate sources of spoilage, such as ripening fruits and root vegetables with sprouts.
- There is a significant difference between daytime and nighttime temperatures, for example, at altitudes above 1000 m above sea level and most latitudes with temperate climates.
- Storage is necessary for relatively short periods.
In most developed countries ventilated Cold storage for vegetables storage, mainly apples and pears have been largely replaced by refrigerated storage due to increased market demands.
However, ventilated storage of fruits such as apples, pears, and lemons are still used widely and with great success in many developing countries.
Most tropical fruits are not suitable for ventilated storage even for short periods, because of their rapid maturation and respiration rate. Certain vegetable crops offer good opportunities for ventilated storage. Some examples and storage conditions are given below.
In conclusion, choosing the correct Cold storage for vegetables technique depends on:
- The type of product, its temperature at harvest time, or its respiration rate and quality;
- The most appropriate storage temperature and humidity for the product and the projected storage time, without implying cold damage or unnecessary microbial deterioration;
- The aptitude for the market and its needs and above all, the economic aspects of the entire operation.