Department of Food Science and Technology
University of Nigeria
The Cooperative Research Programme of Fish Technology in Africa is supported and coordinated by FAO. It has been established in order to pool limited resources of African institutes. The Programme consists of periodically held expert consultations in which research is reported and a new research programme is established as a guideline for national and international institutions. Areas of research cover traditional as well as modern small-scale post-harvest fish technologies. Some research projects are supported by FAO. In order to reap full benefit from this networking approach, additional funds would be required. An example of applied research carried out in the framework of the Programme is included as an annex: viz., A case study on characterization of traditional smoked-dried fishery products in Nigeria, in which water activity is used as the basis for characterization.
Le Programme coopératif de recherches sur la technologie du poisson en Afrique est appuyé et coordonné par la FAO. Le but du Programme est de mieux utiliser les ressources limitées des institutions de recherche africaines dans les activités de recherche. Celles-ci visent à mieux utiliser les captures de poisson. Le Programme est constitué de consultations d'experts, qui ont lieu périodiquement. Ces dernières établissent un rapport des recherches et de nouveaux programmes de recherche sont établis pour servir comme ligne directive aux institutions nationales et internationales intéressées. Les domaines de recherche comprennent les technologies traditionnelles et modernes à petite échelle. Pour tirer le maximum de bénéfices de ce réseau d'institutions, des ressources financières additionnelles seraient nécessaires. Un exemple de recherche appliquée, menée dans le cadre du Programme, est rapportée en annexe: il s'agit de la caractérisation des produits traditionnels par l'activité d'eau, et non par le taux d'humidité.
Fish is an important source of protein food in developing countries. However, fish is highly perishable especially in the hot climate of Nigeria where insanitary environment and poor handling facilities/practices worsen the situation. A high proportion of artisanal catches fails to reach the market in prime form, particularly those markets far from areas of production. The lack of adequate fish handling, preservation and processing methods contribute significantly to the low supply of fish to poor rural dwellers that form three-quarters of the population in developing countries.
The Food and Agriculture Organization (FAO) has contributed greatly to the development of the food and agricultural sector, including fisheries through national and regional fishery development projects. Among the activities funded by the Regular Programme of FAO is the Cooperative Research Programme on Fish Technology in Africa, established by FAO following recommendations of the Regional Seminar of Senior Fish Processing Technologists held in Dakar in 1977. The Cooperative Research Programme is designed to come up with answers to problems associated with handling, preservation and processing, especially at the artisanal level.
The FAO Cooperative Research Programme on Fish Technology in Africa is not an institution with its own status, office, personnel and budget, but a network concept facilitating coordination of effort in research and development of fish utilization, in particular at artisanal level, by various institutions. Such efforts are supported by the Fish Utilization and Marketing Service at the FAO Headquarters through both research grants and the organization of periodic expert consultations. Support is further given by various institutions, both at national and international levels. The United Nations Economic Commission for Africa, the Norwegian Agency for International Development, the Canadian International Development Agency, DANIDA, FINNIDA and the African Development Bank are a few of the institutions that have been involved.
A work programme is adopted during the period Expert Consultations. Fish technologists from Africa and beyond consult and agree on areas in which further action is required; and countries for which the proposed activities are of particular relevance are notified and encouraged to embark on research studies. Consultations have been held in 1980 (Dar-es-Salaam), 1982 (Casablanca), 1985 (Lusaka), and 1988 (Abidjan). These consultations provide a unique opportunity for African fish technologists to meet colleagues, exchange information, discuss problems and elaborate a programme of applied research to be carried out in the period until the next consultation. The last consultation held from 25 to 28 April 1988 in Abidjan was attended by over 80 participants from 17 African countries and 8 non-African countries or international institutions.
2. PRESENT AND POTENTIAL IMPORTANCE
The importance of research in contributing to national development cannot be overemphasized. However, in Africa research capacities in fish technology are limited. Institutes are scattered and generally not adequately equipped while scarce funds do not even permit full utilization of the limited staff and equipment resources. The network approach through collaboration and sharing of resources seems to be most appropriate.
Research areas under consideration include but are not limited to fresh fish handling, fish smoking, fish drying, prevention of post narvest losses, fish marketing and trade, quality control and inspection. Fresh fish marketing and fish processing are important and prominent activities in the region: fresh, smoked and dried fishery products being the most common fish items marketed. Supporting activities such as research, demonstrations, training, and quality control are still weak and there is need to create more institutions to carry out these activities, as well as strengthen existing ones. Hence the continued need for the cooperative research programme. It has achieved much. There is an urgent need for expansion. There is no doubt that, with a good communication network system, fish technologists all over Africa involved in the cooperative research programme, will have at their disposal research findings that will enable various countries cope with one of the challenges of our time - adequate food for all. The need for improved communication and better coordinated research activities between fish technologist in Africa will continue to be of paramount importance.
The Cooperative Research Programme has made valuable achievements in:
fostering research and technical cooperation among participating institutes;
strengthening national research capabilities;
facilitating information exchange and transfer of technology, consequently inducing improved communication and better coordination;
The level of participation in the expert consultation is a clear sign of the growing interest of member countries in this programme. It is, however, regrettable that its financial situation is limited and, unless proper funding is worked out, the future of this programme will be jeopardized. Specifically, one can say that progress has been made in the following areas:
Fresh Fish Handling:
In this area insulated fish containers for handling fish on board and ashore have been constructed and successfully tested in different parts of the Senegalese coast, Benin, Togo, Tanzania, Tunisia, Kenya, and Malawi. Materials for construction of these containers range from locally available materials (Tanzania) to fibreglass, polyester resin and polyurethane foam used in Senegal. Insulated containers and ice allow artisanal fishermen to make longer trips. The catch can be marketed as fresh fish which fetches higher prices than when used for processing.
The Chorkor oven has received much attention. It has been been compared to other ovens like Altona, round mud, drum and pit. Results from Ghana indicate that the Chorkor is the best in terms of fuel consumption, smoking time and ease of operation. A large quantity of fish is smoked in Chorkor - the village in Ghana where the Chorkor oven was developed - and the ovens installed there, after many years of use, proved that the design is appropriate for artisanal operations and needs. The Chorkor oven has been demonstrated by FAO, or in collaboration with FAO, in many countries including Sierra Leone, Senegal, Gambia, Cameroon, Kenya, Uganda, Rwanda and Haiti.
With regard to prevention of post-harvest losses, significant progress has been made in the elaboration of a methodology for estimating post-harvest losses of cured fish. A Dutch regional training project on fish technology was started in Ghana, with prevention of post-harvest losses as a major element. A study was carried out on post-harvest losses in West African fisheries and a publication on prevention of post-harvest losses has been published by FAO.
In the area of fish marketing and trade, FAO's INFOPECHE project has been established and is serving African countries in promoting intra- and inter-regional trade in both traditional products (smoked, dried, etc.) and non-traditional products (frozen, fresh, etc.). In addition the project provides technical advisory services to fish processors and traders.
Regional workshops on fish technology and quality control have been organized in Senegal, Angola, Tanzania; and national workshops in Cape Verde, Ethiopia, Mozambique, Uganda and Guinea-Bissau. Since the FAO/DANIDA programme started 15 years ago, a total of 254 participants from 40 different African countries have received training in this field.
4. FINANCIAL SUPPORT
FAO's support to the Cooperative Research Programme which includes financing and coordinating the programme activities, organizing consultations and disseminating information has been recognized. However, FAO's Regular Programme resources under which this support is funded are neither adequate to play the important coordinating role required nor are they sufficient for effective strengthening of the network on a regional level. There is an urgent need for financial support from other organizations if the Programme is to survive. FAO has taken a bold step by starting the Cooperative Research Programme on Fish Technology. However, the financial commitment required is enormous. FAO cannot handle this alone. This is particularly important in view of the significant deterioration of the financial situation of research institutes in most African countries.
The effects of financial constraints on the programme are glaring. Proceedings of the last Expert Consultation held in Abidjan from 25 to 28 April 1988 were only published in March 1990, two years after the consultation. Research grants given to institutions are now only enough to buy some of the laboratory chemicals needed for research. There is, regrettably, absence of much-needed regional and national workshops to promote technical cooperation among developing countries in special areas.
The programme's role as a technical advisory body to national and international institutions and agencies would become more evident if additional funds were made available for information gathering and dissemination, for support of applied research, for demonstration, and pilot activities, for exchange visits of experts, and for the organization of the expert consultations. The experts in previous consultations have noted significant progress made in the programme and strongly recommend its continuation and strengthening through increased availability of financial resources.
The Cooperative Research Programme on Fish Technology in Africa has aimed at accelerating the development of fish technology in Africa through collaboration between African technological institutes and improving communication between them in order to establish a proper mechanism of exchange of experiences with the main objective of reducing post-harvest losses in fisheries. Besides the support it has provided to research institutes which have carried out projects of common interest, the programme has organized consultant studies and expert consultations which have gathered together specialists from within the West Africa subregion and other African subregions. Considerable progress has been made. However, financial constraints hinder expansion and efficiency of the programme. External support for this programme could significantly improve post-harvest operations.
ECA/FAO. 1987. Measures for improving the utilisation and marketing of fish in West Africa; United Nations.
FAO. 1985. Report of the FAO Expert Consultation on Fish Technology in Africa. FAO Fish. Rep., (329), Rome.
FAO. 1989. Report of the FAO Expert Consultation on Fish Technology in Africa. FAO Fish. Rep., (400), Rome.
CHARACTERIZATION OF TRADITIONAL SMOKED-DRIED FISH IN NIGERIA
In previous FAO Expert Consultations on Fish Technology in Africa and other conferences, scientists in Africa have used to a great extent percentage moisture content as a basis for describing available water. In the last Expert Consultation held in Abidjan, all the participants agreed that the use of water activity (Aw) should be encouraged. Water activity (Aw) is the basic parameter to describe technically all the classic cured fish products (salted, salted-dried, dried and smoked) and to assess their stability regarding micro-organisms, enzymatic activity, hydrolytic reactions and rancidity development (1). Within certain limitations it also provides useful information with relation to insect infestation (e.g., minimal Aw for fly to lay eggs). The Aw is important because it gives a quick estimate on safety, stability and problems associated with cured food. Extensive tables giving the minimal Aw values at which deteriorative micro-organisms can develop have been published (1).
The idea of characterization of traditional smoked-dried fish in Nigeria is new. Little has been reported in this regard. Motwani (2) reported that of all the 160 species of fish identified in Niger-Benue system, 44 are commercially important. These include Alestes spp., Arius spp., Auchenogalaria spp., Bagrus spp., Citheridium spp., Eutropius spp., Gnathoremus spp., Schilbe spp., Lates spp., Gymnarchus spp., Sardinella spp., Clarias spp., Tilapia spp., Ethmalosa spp., Heterosis spp., Chrysichthys spp., Clupisudis spp., Synodontis spp., Hydrocynus spp. Species in Kanji Lake are very similar to those listed above except that according to Turner (3), the Citharinidae especially Citharinus citharus tends to dominate the catch in most seasons of the year. In Lake Chad the species are also much the same as in Kanji and the Niger-Benue complex, but the individual fish tend to be much larger than those in other areas.
My colleagues and I at the University of Nigeria, Nsukka, have since July 1989 been working on the characterization of traditional smoked-dried fish in Nigeria. The initial study has involved 20 species. The objectives of this study are:
To determine the technical characteristics of traditional smoke-dried fish in Nigeria, in particular the proximate composition (protein, fat, water and ash), and the water activity (Aw).
To determine the degree of: insect attack; mould infestation; tendency to fragment.
To utilize the results obtained to rationalize the knowledge on smoke-dried fish for training purposes.
The Department of Food Science and Technology, University of Nigeria, Nsukka, received support (chemical and Aw meter) from FAO towards this project.
The Aw meter (filament hygrometer) used was introduced during the FAO/DANIDA Workshops on Fish Technology (1982–1986).
Samples of different smoked-dried fish species traditionally processed were taken (i) after processing, (ii) during storage and (iii) from markets, and were analysed. Results obtained are shown in Tables 1 to 4.
Insects were not observed in freshly smoked-dried fish. Insects later gained entry into them during storage, in transit or in the market. The degree of fragmentation of the traditional smoked-dried fish is a function of the level of moisture in them. The higher the moisture content of the fish the lower the degree of fragmentation; that is, freshly smoked-dried samples from the production site with higher moisture contents have relatively less tendency to fragment than the market samples that have lost much moisture, particularly due to redrying by the traders. Maintaining a high moisture content in the products counters fragmentation, although the fish would be readily attacked by moulds. Types of species also play a role in determining the degree of fragmentation. In this study, Bagrus bayad, for example, had a higher tendency to fragment than Protopterus annectens. Of major importance is the degree of freshness of the raw material: the lower the quality the higher the tendency to fragment.
The proximate composition and sodium chloride contents of the traditional smoked-dried fish samples all depend on the degree of dryness of these fish. Quantitatively, they are inversely related to moisture and also vary with species of fish.
Provided they are freshly smoked-dried and intermittently redried, it is rare to observe mould growth visually on smoked-dried fish from the production site and even from the market. However, when freshly smoked-dried fish with high available water are stored under ambient conditions, mould growth becomes the major cause of spoilage. The moulds identified provide an indication of the genera most likely to be responsible for the spoilage of smoked-dried fish.
The data on Aw provide better criteria for assessing the stability of the smoked-dried product. Moulds grow on products with Aw as low as 0.71. The determination of Aw using filament hygrometer is less cumbersome and results more reliable when compared to moisture content. There is need to characterize all the commercially important species and also to conduct this research in various parts of the country at different seasons of the year. However, there are financial constraints. FAO cannot proceed alone; support from other organization will be necessary.
Lupin, H.M. 1986. Water activity in preserved fish products. In: Cured fish production in the tropics. University of the Philippines in the Visayas, Diliman, Quezon City, Philippines, 14–25 April 1986; pp 16–55.
Motwani, M.P. 1970. Fisheries investigation on Niger and Benue Rivers in the Northern Region and Development of a programme of riverine fishery management and training. FAO Report to the Government of Nigeria, 1970.
Turner, J.L. 1971. The Fish Population of the newly Improved Kainji Lake in Nigeria. Journal of West Africa Science Association, 16, pp 49–53.
Proximate composition, sodium chloride and water activity
of traditional smoked-dried fish samples
obtained from the production site
Proximate composition, sodium chloride and water activity
fof traditional smoked-dried fish samples
obtained from the market
Effect of storage on moisture content and water activity of the fish samples
|Chrysichthys nigrodigitatus||Clarotes laticeps||Alestes nurse||Synodontis clarias||Distichodus rostratus||Hyperopius bebeoccidentalis||Lates niloticus||Labeo senegalensis||Clarias lazera||Tilapia nilotica|
|Ethmalosa dorsalis||Heterotis niloticus||Gymnarchus niloticus||Channa obscura||Hepsetus odoe||Malapterurus electricus||Citharinus citharus||Bagrus bayad||Pseudolithus senegalensis||Protopterus annectens|