Saturday, January 10, 2015

Extending the life of perishables-A new non-electric system tailor-made for small scale growers

Since ages one has been hearing about food wastage due to improper post harvest handling and storage. While developed countries have created highly efficient cold storage, modified atmosphere storage and cold chain infrastructures for reducing the losses due to respiration, transpiration and microbial spoilage, in many developing countries the technology required is neither available nor practical because of power shortages. Spoilage in these countries is variably estimated from 25 to 50% of total production. Grower income is adversely affected because of deterioration of quality by the time the produce reach the market. It is tragic that while farming community is able to rise to the occasion in meeting the increased demand for food by the ever expanding population, their efforts are not complemented by establishing necessary infrastructure facilities by the governments in these countries. In a new initiative by some enthusiastic entrepreneur set up, a solar based preservation technique has been developed that can extend the shelf life of most fruits and vegetables by a few days. Here are further details about this significant innovation with wide application potential in Asia, Africa and South America.

"In addition to a 3 W solar panel, the device comprises a top-loading tent-like structure, in which up to 150 kg (330 lb) of produce can be stored, and a solar-powered ventilator. The ventilator gradually evaporates a weekly supply of 200 ml (6.7 fl oz) of water creating a humid environment within the tent. Company founder Arne Pauwels explains that the humid environment created by the Wakati helps to reduce the extent to which crops dry out after being harvested. As a result, he says, the cells of the crops are kept intact and the acids and enzymes inside the cells that would (t ) otherwise begin to digest the crops are kept contained. Unlike a refrigerator, the Wakati does not control temperature and, therefore, cannot store fruit and veg for long-term periods. Pauwels says, however, tests on the Wakati have shown that a one or two-day shelf life in a hot climate can be increased to 10 days. This can increase the amount of time that produce can be stored in developing countries before sale, reducing the amount that goes to waste and maximizing the amount of profit that can be made by the grower. The first batch of 100 Wakatis has already been supplied to Haiti, Uganda and Afghanistan and Pauwels says that the company is ready to go into full production at an initial cost of US$100 per unit (though it is hoped that increased production will drive that figure down)."

The fact that the new technique is just managing to increase the life from 2 days to 10 days may not match it in terms of performance to that of industrial scale cold storage but still it can make a lot of difference to the income of a small scale farmer growing perishable in small plots of land in village areas where electricity availability is like a lottery with no assurance of its supply for long duration of time. This contraption is similar to the evaporative cooling chambers developed long ago which did not find many takers. The major difference is that in this version evaporation is achieved through solar energy in stead of by forced circulation of water in the earlier model. The cost indication of $ 100, equivalent to Rs 6000 may be on the higher side but in India such chambers can be built at half the cost with solar panel costs prevailing at Rs 50 per watt. An uncertainty that may pose challenges in establishing such chambers in large numbers in fruit and vegetable growing areas is the missing cold chain services which will have to carry the preserved produce to the market place in prime condition. More appropriately such solar based cold chambers will be more suitable for farmers' markets and farms feeding such markets or shandies as they are called in rural areas in the country.


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