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Dr. ir. Marcel Herregods
Petrusberg 20
B-3001 Heverlee (Belgium)
Tel.: +32 16 40 41 75 Fax: +32 16 20 30 35 E-mail.: +32 16 40 41 75 Fax: +32 16 20 30 35 E-mail : vbt@tornado.be
There is a growing interest in all areas for storage and transportation of horticultural products, because the products are very perishable and because of the long distances between countries and their major export market.
Worldwide postharvest fruit and vegetables losses are as high as 30 to 40% and even much higher in some developing countries.
Reducing postharvest losses is very important; ensuring that sufficient food, both in quantity and in quality is available to every inhabitant in our planet. The prospects are also that the world population will grown from 5.7 billion inhabitants in 1995 to 8.3 billion in 2025.
World production of vegetables amounted to 486 million tonnes, while that of fruits reached 392 million tonnes.
Reduction of post-harvest losses reduces cost of production, trade and distribution, lowers the price for the consumer and increases the farmers income.
Distribution of vegetables and fruit production in the various regions (in million tonnes)
| Vegetables | Fruits | |
| North and Central America | 44.16 | 53.17 |
| Europe | 66.98 | |
| Europe | 66.98 | 65.17 |
| Africa | 35.20 | 54.06 |
| Asia | 292.41 | 142.24 |
| Pacific | 2.60 | 5.62 |
| South America | 16.06 | 60.95 |
(FAO)
| Vegetables | 486 | 57 | 5 |
| Fruits | 388 | 53 | 2 |
The increase in prosperous population, the urbanization and the green revolution have enlarged the market for all kind of ornamentals.
Postharvest research has a high return.
Significant contributions, minimizing the postharvest losses have been made through research on the physiological changes in the product after storage, new longlife varieties, suitablthe product after storage, new longlife varieties, suitable cultivation circumstances, optimum harvesting indices, recommended storage recommendations, precooling refrigerated transport and careful handling.
In preserving the quality of the produce reaching the final market, the whole marketing chain from the producer to the final consumer must be examined for any weakness.
The postharvest research topics have to be closely related to the socio-economical and financial situation, the climatical and cultivating circumstances, the market organization and the requirements of the specific commodities.
The current needs of scientific research and extension services are different between developing and high developed, industrialized countries, and the nature of the projects must be adapted, step by step, following the evolution.
In this respect, the possibilities of linkages and further international research cooperation has to be stimulated by international institutions such as EC, FAO, ISHS, HR, and through initiatives such as the World Conference on Horticultural Research.
Postharvest research is definitely a mutidisciplinary endeavour
of biology chemistry, physics, pathology, biochemistry, physiology,
marketing, financing, psychology and ethics in a social-economical,
political and financial context.
1. Suitable post harvest research in developing countries
Pole post harvest research in developing countries
Post-harvest research has to be not only limited to storage conditions but also to market requirements, breeding and cultivating circumstances.
Treatments to arrest deterioration, harvesting at correct maturity, precooling to reduce field air, care during sorting, packaging, transportation are also determinent post-harvest factors.
Some methods of handling, packing and storage have been developed over years, using innovative abilities and skills, also low cost and commonly available materials and technolgies.
In other methods different new techniques and disciplines are
implemented.
Market situation
Roadside markets with small shops or a type of local marketing are seen commonly at the suburbs of a city and in rural districts, mostly close to farms and selling seasonal products.
Price differences according to quality are mostly too small and don't stimulate enough quality improvement.
Urban population is exploding in developing countries, rising from 35% of the total poplation in 1990 to 54% in 2020. With this increasing urban population more free market and wholesale markets will be required.
Product is shipped from neighbouring areas as well as from distant ones.
Comparison with imported products stimulates increase of the quality
of the regional produce. Export will make clearly show whatuality
of the regional produce. Export will make clearly show what quality
level is needed for exported produce. Continuously following consumers
and traders requirements, growers have to be informed in the choice
of the varieties, the cultivating techniques and the extending
of the selling period. The presence of growers cooperatives or
collecting centers for selling products and the requirements of
exporters and supermarkets could stimulate for applying suitable
varieties cultivation methods of sorting, grading and transporting,
and establishing research activities and extensions services.
Cultivating conditions
Many small growers produce a high variability of crops, in the villages for self consumption and around the cities for selling the rest. Changing the choice of the varieties and the cultivating techniques is the most important and must be oriented to a higher quality and healthy product, prefered by consumers and with a longer shelf-life required by traders.
Pest control with plant extracts has to be improved.
New developments presume proper financing possibilities, not always easy to get.
Exceptionally some big specialized growers produce a high quantity
of nice products for export as Phaseolus beans in Senegal or mangos
in the Philippines.
Grading and sorting.
Quality standardisation <>
Quality standardisation
Grading and sorting in quality classes is limited or not existent
and this evolution can be stimulated by the development of cooperative
selling organisations.
Packaging
Packaging is dependant on the disposal of packing material in
the country (bags, wooden crates, woven baskets). Adaptations
are necessary to reduce bruising by filling and transportation
and to increase shelf life. The evolution is to use standardised
reusable plastic boxes and suitable corrigated carton boxes, after
wooden crates.
Transportation
Most growers have only at their disposal limited transport facilities as bicycles, three wheeled or small trucks.
Some traders with bigger trucks can buy the products in the producting area and transport them to the markets in the cities, with high profit.
Due to the poor condition of the roads there is a rapid deterioration of the produce in some areas.
Cooperatives could place at the disposal of the growers suitable important transport vehicles.
In developing countries a few number of exporters transport proper
packed and graded product by refrigerated trucks, air of boat
on commissions (± 10%) to countries far away.
Storage and processing
Storage technics are mostly limited tStorage and processing
Storage technics are mostly limited to evaporative cooling or ventilated cooling with air in winter and cold water in summer (humypad cooling) or storage in caves. These technologies have to be optimized and complemented by proper ventilated or simple modified atmosphere systems.
Refrigerated warehouses in developing countries are located mainly in large cities and ports but very limited in the farmers area (garlic in Beijing).
Refrigerated storage rooms have to be developed in the production areas.
In developing countries the introduction of new expensive, not ozone degrading cool media is not easy.
Research on the optimum cooling techniques of different commodities, to improve shelf-life, have to be studied, as long-life cultivars applying biotechnology technics, better cultivating techniques and pest control, harvesting using objective maturity indices.
Reducing bruising during harvesting packing and transport, picking in the morning, putting the product in the shadow and increasing the speed of selling times, are key basic elements for quality.
To prolong storage time, heat treatment of fruit, curing of root-vegetables after harvest, chemical treatments of flowers, treatment with growth regulators or wax of fruit and vegetables, chemical drying of onions before harvest are important element.
To preserve fruit and vegetables in developing countries research
on solar drying, laetables in developing countries research
on solar drying, lactic acid fermentation (kimchi), fresh pack
fruit added with the juice of tropical berries with very high
Vit. C en low pH or antibrowning agents as grapefruit seeds must
be stimulated.
Information to growers through extension services
The current emphasis of the post-harvest extension services is to reduce losses, increase quality, to invest low cost suitable technology, using suitable financing.
Proper information is necessary to help the sometimes poor and exploited producers with technical and marketing assistance, for more market directed crops.
It is recommended that a structural system for education and training
of growers will be implemented.
2. Suitable post-harvest research in industrialized countries
Industrialized countries, research is related to more fundamental
research, and characterized by the introduction of far advanced
expensive technologies and the integrataion of different scientific
disciplines.
Market situation
Specialized wholesalers-exporters and retailers and supermarkets require big quantities of the same quality.
Farmers have to concentrate their production through cooperation, selling big quantities of the same quality, offering a variability in crop by remote selling, and supplhe same quality, offering a variability in crop by remote selling, and supply on a long period. Competitiveness is increasing, mostly with commodities from tropical countries, inducing some problems in selling final produces.
There exist a consumer preference, different from market to market with also market segments.
The relationship price-specific quality indice is studied for different markets (Northern Europe red tomatoes, Southern Europe pink).
For long storage time the elasticity supply-demand factor is important.
Export market research will make clearly show what level is needed for exported produce and will help to find new suitable markets.
Communication and information of the consumer about quality (health,
nutritive) and the promotion of the product means a sophisticated
knowledge and experience. Quality of food is quality of life.
Cultivating circumstances
Few farmers produce high quantities of an high quality product. They are very specialized in one crop and a few numbers of cultivars.
Through breeding and molecular biology techniques long-life and disease resistant varieties are created. The cultivating techniques and pest control methods are modelled and optimized. In the last time most interest is given to healtly aspects by integrated fruit production and environmental friendly fertigation. The supply is extended through plastic covering and glasshouses, he supply is extended through plastic covering and glasshouses, also through storing of plants as strawberries and raspberries for later forcing.
Objective indices and apparatus indicating optimum harvest are
generally available. The application of postharvest chemical treatments
by drenching, dipping or fogging is decreasing for consumer healthy
objectives. There is yet some interest for heat treatments and
wax coatings.
Grading and sorting. Quality standardisation and determination
The EC quality categories E, I, II for sorting and size (mm) or fruitweight are generally practised. This distinction is no more sufficient for traders besause external and internal quality in one quality category is changing too much.
Selling boards make own quality blocks between one category (red and ground colour for apples, morphologic aspects for vegetables). Also some supermarkets require minimum quality norms for quality (colour, brix, titric acidity, firmness).
For controled integrated fruit production labels for quality insurance
are applied. International standardization of analytical and equipment
is necessary. For controlling quality and automized sorting non-destructive
methods are studied based on physical, acoustic, optical, electric
impedance, X-ray, chlorophyll fluorescence and nuclear magnetic
resonance technics. For export to some countries or quarantine
security is required.
some countries or quarantine
security is required.
Packaging
Standardisation of the dimensions of package (60 cm x 40 cm, 30 cm x 40 cm) and the pallets (80 cm x 120 cm, 100 cm x 120 cm) is far advanced.
After wooden boxes reusable uniform plastic boxes - sometimes pliable - are used (Europool).
Corrugated carton boxes with minimum compression and minimum 4,5% open air locks after humid air precooling and long transport are available.
Modified atmosphere packaging with absoption layers for water and ethylene, and inserts are used. For expensive products, PP films with a wide range of micropores are of great interest. The presence of some pathogenic organisms need urgent research.
The desinfection of wooden boxes with fomaldehyde or azaconazole is important for long time storage in high humid circumstances.
Labels on boxes or product have to inform consumers about the origin, the quality and the welfare of the product.
Increasing attention is given to fresh product, fresh pack and
tightly processed products and juices.
Transportation
To meet the nutritional needs, higher amounts of food will have to be transported over greater distances and for a further extended time. Refrigerated trucks and containers are more used.
To reduce the dependence on expensive rapid air transport, CA
refrigeraP>
To reduce the dependence on expensive rapid air transport, CA
refrigerated trucks and containers are performed. Accordingly,
maximum values for impact and vibration norms are recommended
for trucks on normal roads.
Storage and processing
On construction level there is an evolution from cheap cork or glass fiber insulations, and bitumen or paint gastightness to gastight polyurethane-metal panels.
Requirements for compressor capacity and relative humidity increase. New not ozone degrading refrigerant are used. Compared to regular storage, modified atmosphere, controlled atmosphere, ultra low oxygen storage, quick pull down of oxygen and ethylene absorption are now suitable according to costs of investments and price.
New temperature, CO2 and O2 sensors for scrubbers and membrane separators are favoring monitoring and lowering risks of not proper storage. Precooling with humid forced air cooling and ice bank has a lot of benefits for vegetables and berries.
For each commodity specific storage conditions are dressed. CA storage for tropical fruits, vegetables and fresh pack products is recommended. To extend the supply of berries, storage of plants is applied. During storage, chemical treatment of flower with preservatives is well developed.
In processing development of juices, purees, extracts and essences
significant progress is perceptible, with new technics nces
significant progress is perceptible, with new technics as microwave,
membrane separations, ultrahigh temperature, aseptic package.
3. Future post-harvest research priorities
4. International post harvest research cooperation
Post harvest research has to be adapted to the specific post harvest problems in each countries - according to the cultivated commodities and the socio-economical, technical and financial situation. International contacts between scientists and international cooperation projects will be very important in future to accelerate the evolution in developing countries especially.
The information of existing research programmes in the world collected on ocassion of the World Conference on Horticultural Research will be very helpful to determine the post-harvest priorities for each country and to stimulate cooperation.
International organisations such as ISHS, ASHS, EC, FAO, could
there after contribute considerably in extending post harvest
networking, research contacts and cooperation and to support some
priority research projects, together with the existing govermental
research and extension service.