From crops to shops: improving the post-harvest sector

With the expansion of international food trade and the continued escalation in population growth, global consumer demand for larger quantities of high quality and low cost processed foods has created considerable interest and investment in the development of new or improved post-harvest technologies. This is particularly important for developing countries where post-harvest losses of cereals is between 10-20% and of fruits and vegetables as high as 20-100%. In the past, post-harvest research used to focus on small-scale farmers who needed to preserve their harvest to ensure food security for the household but new, innovative post-harvest systems are allowing farmers to generate more income by adding value to their crops. These systems also allow the generation of off-farm employment for people involved in the processing, transportation and marketing of food products. Efficient postharvest systems are particularly important as competition for land and water increase and, with migration of rural people to urban centres, there are likely to be fewer farmers producing food for more consumers.

To address the needs of the post-harvest sector and to raise the profile of innovative post-harvest activities, ten institutions are collaborating, with a range of public and private sector partners in developing countries, as part of a new global forum, PhAction. Improvements currently being promoted by members of PhAction include designing and disseminating improved equipment, delivering more efficient or environmentally sound uses of technologies, developing higher value products, implementing more efficient food policy and improving services that enable producers to access more markets.

Low-cost technologies

To meet the needs of small-scale farmers that have difficulties competing on the open market with produce from larger, more efficient farms and imported goods, development agencies have generated a range of low cost, crop and food processing technologies. For example, to address the problem of drying, which is the most important and critical operation after harvesting rice, IRRI developed a simple, low cost mechanical dryer for small-scale farmers in Vietnam. The dryer was for use on small rice farms (<1ha) in urban or rural areas with access to electricity. Over 700 dryers were installed in early 1998. Design modifications resulted in a reduction of drying time and choice of materials that would benefit wider adoption. Technical drawings and manuals of the dryer from IRRI have been made available free of charge with the result that the dryer has since been copied and modified by small manufacturers in many parts of Asia and the technology is spreading to other rice producing countries. It is estimated by FAO that a 10% saving of post-harvest losses in Asian rice would result in a saving of 5 million tonnes of food a year.

Cassava processing technologies which enable farmers to produce high quality flours from cassava, sweet potato and yam within one day rather than 1 week are making progress in much of Sub-Saharan Africa with the support of IITA. These small-scale technologies provide farmers with the opportunity to add value to what is normally considered a famine reserve crop and, by producing a higher quality product, farmers can both expand sales in existing markets and initiate sales in new market areas. The cassava processing technology, which was first introduced into Nigeria, is now being actively promoted in East and Southern Africa through new CGIAR research and technology networks such as EARRNET, FOODNET and SARRNET.

In relation to higher value crops, the Integrated Food Crops Systems Project, in Ghana, has introduced a number of adapted solar drying techniques that were found to be very effective for processing horticultural crops such as capsicum peppers. Similar methods have proven to be very successful in drying fruit crops for export in Uganda and rural Zimbabweans are using various traditional solar drying techniques for processing a range of indigenous vegetables. NRI will be starting a new project, in November 1999, to investigate relevant food safety and quality issues for improving production and also seeking new types of trade linkages so that small-scale farmers can begin to access more lucrative export markets.

Environmental considerations

Storage pests are a serious problem for many small-scale farmers. Fumigants commonly used against pests are expensive, can affect human health and those containing methyl-bromide have been banned for their depleting effect on the ozone layer. The larger grain borer (LGB) - Prostephanus truncatus - has been a particular problem for maize farmers in Africa. However, after successful collaboration between several agencies, including GTZ, NRI and IITA, biological control of the pest has been successfully achieved in the Republic of Benin and in Togo by its natural enemy, the predatory beetle (Teretriosoma nigrescens).

Inert dusts, particularly diatomaceous earths (fine dusts composed of phytoplankton fossils), offer a safer alternative to synthetic chemical insecticides for grain protection. On-farm trials carried out by NRI in three districts of Zimbabwe have shown that the commercially available diatomaceous earths Protect-it™ and Dryacide® can protect maize, sorghum and cowpeas against insect damage. A local source of diatomaceous earth has also been located in Northern Zimbabwe, and preliminary investigations have shown good efficacy against some storage pests.

Niche markets

In Latin America, CIAT has developed an integrated methodology for rural enterprise development which has been applied successfully with cassava farmers in several countries. This participatory approach involves farmers working with researchers or an NGO to select the most appropriate technologies in order to access the best market opportunity for cassava. For example, in Colombia, improved technologies for producing cassava chips were promoted to supply the expanding market for animal feed concentrates. This innovative rural agri-business development model is now being applied by IITA in Africa for cassava and, in Latin America, the approach is being broadened to include a range of crops and products.

Minor crops, such as fonio that are popular with consumers but suffer limited production because of post-harvest constraints, are also the target of renewed research efforts. CIRAD, is to launch a four year project in association with institutions in Burkina Faso, Guinea and Mali to improve post-harvest techniques; promote fonio products for urban markets and for export; and to enhance information dissemination in the twelve West African producer countries.

Policy changes

A recent IFPRI project for small-scale rice growers in Vietnam demonstrated that a modest series of changes in market policy would significantly increase the profitability of this sector and reduce levels of government support by several million dollars per year. The Vietnam Government responded to the advice and, although such actions may appear subtle to individual farmers, it has been shown that these moderate changes can make the difference between subsistence farming and incremental, sustainable growth.

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