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close this book Food chain - Number 19 - November 1996
View the document Contents
View the document Greetings
View the document Food processing training - some problems and possible solutions
View the document Booklines
View the document Principles of food dehydration
View the document Simple methods of quality assurance
View the document Research notes
View the document Food preservation by the Turkana people.
View the document Ayib (traditional cheese)

Food chain - Number 19 - November 1996

A journal about small-scale food processing

INTERMEDIATE TECHNOLOGY

Intermediate Technology enables poor people in the Third World to develop and use technologies and methods which give them more control over their lives and which contribute to the long-term development of their communities.

Contributions on all food processing related matters are invited for future issues of Food Chain.

No. 20 March 1997

No. 21 July 1997

No. 22 November 1997

ADDRESS

Intermediate Technology,

Myson House, Railway Terrace,

Rugby, CV21 3HT, UK.

Tel: 01788 560631

Fax: 01788 540270

Food Chain is funded by the UK Overseas Development Administration. Editor/Production Manager: Ann Watts Technical Editor: Barrie Axtell Typeset by My Word! and printed by Neil Terry Printing on environmentally friendly paper.

Intermediate Technology Development Group Ltd.

Company Reg. No. 871954, England. Reg. Charity No. 247257.

ISSN 0964-5810

 

 

Contents

Greetings

Food processing training - some problems and possible solutions

Booklines

Principles of food dehydration

Simple methods of quality assurance

Research notes

Food preservation by the Turkana people.

Ayib (traditional cheese)

 

 

Greetings

I have been in contact with some of our readers for many years now and it feels like old friends writing. I have always enjoyed this contact with you and hope that it may long continue. Please keep writing...

Many thanks to all of you who have returned the questionnaire which was sent out with the last issue of Food Chain. It is amazing just how many of you are using Food Chain either as an information resource in libraries, reproducing the material in your own newsletters, translating it into your own language or using it for training courses. This information is precisely what is needed to support applications for Food Chain's continuing production. If you have not yet returned your form, please do so- it is not too late to send it and the information is so useful.

For some time now, we have been planning to incorporate a training element into Food Chain The results from the questionnaires received to date, indicate that it is being used widely by readers as a foundation for their own training courses and so this has prompted the introduction of the training element for this issue. Several respondents state that the information in Food Chain is clear and appropriate to the needs of small enterprises, unlike the often theoretical, high technology courses in Universities. As Peter Fellows writes in his article, good training depends as much on the style and approach used by the trainer, as on the actual material used. Good training should not be a matter of the trainer lecturing at participants. The objective is not for the trainer to show how much he/she knows, but rather to allow participants to build on their own existing knowledge. Good participation is the key factor.

In the questionnaire replies, many readers in Africa have suggested that we have a page covering items solely relating to Africa. We would like to do this, but first need the material to publish... We urge readers, particularly those from the developed countries, to share their experiences as these may be of great value to others who do not have free and easy access to information. The Asia pages come from readers in and around our office in Sri Lanka, who then forward it here to be incorporated into the journal. Perhaps if readers in Africa would care to forward material for publication in sufficient quantity, we could have an Africa section too. There are plans for a page from our office in Lima, Peru - relating of course, to South America. This will probably be in the next issue. It has always been the hope that Food Chain would stimulate readers sufficiently to write to us with their experiences and so an exchange of information between countries would develop. It is good to know that this is now happening and we look forward to receiving your ideas and information. It may be that some readers need further help with certain aspects of their work, and there are many of you who are already aware of the Technical Information Services provided by Intermediate Technology. For those who are unaware, you may write in with any technical queries (quoting Food Chain not just relating to agro-processing, but all aspects of development work and we will do our best to answer them for you.

We are also planning in the near future, to have a special edition relating to weaning foods and nutrition. If readers have any contributions to make for these issues, then please send them in. I have been in contact with some of our readers for many years now and it feels like old friends writing. I have always enjoyed this contact with you and hope that it may long continue. Please keep writing...

Warm regards to you all

Ann Watts

Editor/Production Manager

THE SEVENTH POST HARVEST CONVENTION

Post-harvest Chemicals - A Future?

25th March 1997

Post-harvest Technology Department,

Silsoe College,

Silsoe, Bedfordshire,

MK45 4DT, UK.

Tel: +44 (0)1525 863276

Fax: +44 (0)1525 863277

Email: L.Ellis@Cranfield.ac.uk

 

 

Food processing training - some problems and possible solutions

In this article, Dr Peter Fellows describes his observations and experiences of food processing training programmes in Africa and Asia during the last 10 years. He has spent 15 years as a trainer in food processing, initially involved in university training at post-graduate and undergraduate levels and external examining for MSc and PhD candidates. For the last ten years he has worked on the design of practically based training courses for developing countries, design of training centres, preparation and implementation of TOT courses and design and implementation of integrated training programmes for small-scale food enterprise development.

Over the last decade, food processing has increasingly been seen as an important area for rural development, improved food security and small enterprise development by international donors, national Government agencies and NGOs. Because food processing requires a multi-disciplinary approach for sustainable implementation, involving sciences (such as bio-chemistry, engineering and microbiology), social aspects (for example food preference) and economic aspects (such as import substitution, marketing and financial management), in nearly all cases, training is one of the first areas that is implemented in a development project. Most intended beneficiaries are either farmers, householders or existing/aspiring small-scale entrepreneurs and in many programmes there is a focus on women, who are said to find food processing an easily accessible option for improving household incomes or food security.

It is recognized that many people know how to process traditional foods for consumption in the home or for immediate sale to neighbours, and that training in improved storage for food security is therefore able to readily build on existing knowledge. However, in small enterprise development, the concept of producing a packaged product for distant sale and consumption by unknown people is new to many intended beneficiaries. Therefore training programmes are required to introduce unfamiliar ideas such as standardized production and packaging, marketing, production monitoring and control of finances.

However, many training programmes fall short of expectations because of a lack of planning, a lack of understanding of participants' needs or a lack of skills and experience by trainers. In this article, I shall attempt to highlight some of the most common failings and suggest ideas that can be used to improve the quality of food processing training, mainly with a focus on enterprise development courses.

START WITH THE INTENDED BENEFICIARIES

One of the most difficult and intractable problems facing trainers is to deliver training at a level that is appropriate to the needs of participants. Too frequently a food scientist or technologist appears more interested in demonstrating to the trainees how much they know about their subject, rather than listening to what the trainees want to learn. As a result the trainees are 'blinded by science' and emerge from the course having learned little and believing that food processing is a very difficult subject.

To overcome this problem, a first step is to conduct a detailed training needs assessment. This may involve a formal questionnaire of intended participants, but could equally be done by informal visits and discussions with a representative sample of people, to find out what are their main problems and what do they want to learn on a training programme. This can then be used to guide the trainer in course design, content and training methods. Additionally, the results will indicate the most acceptable duration for the training and whether it should be held in a single block or divided into short components, spread over several weeks remember that most participants will have many demands on their time. It should be noted however, that many potential trainees will focus on their lack of knowledge of how a particular food is made or what type of equipment is needed, as they may not be aware of other aspects that are involved in operating a successful food processing venture. The trainer should therefore be ready to introduce ideas such as contracts with suppliers, conducting market research, calculating the sale price, arranging agreements with retailers etc. during the discussions, to determine whether participants consider these to be important for them. In short, the trainer should have a good understanding of the participants' specific needs, in order to design and implement a course that meets these needs.

PARTICIPATION OR LECTURING?

Once a trainer has an understanding of the areas to be covered on the course and the depth of the knowledge that is required by participants to meet their needs, the next problem is how to implement the training. In too many cases, trainers believe that they are the fount of all wisdom on a particular subject and if they talk to participants for long enough, some of this wisdom will somehow become absorbed. The result is hour upon hour of a trainer standing and talking in front of rows of seated people, many of whom are gradually falling asleep and none of whom are learning very much.

I believe that the two most important factors in implementing a training programme are first to involve people doing rather than listening and secondly to structure the programme in a way that participants can learn from each other's experience and knowledge - in other words to implement a participative approach to training. This approach is feared by many trainers either because they are afraid that they may be asked a question to which they do not know the answer (and therefore lose the respect of participants), or secondly because they are not in constant control of the group and cannot predict what will happen during a session.

In response to these genuine fears, it is usually necessary to first conduct a Training of Trainers (TOT) course. When done properly, this will give trainers a new confidence in their own abilities and encourage them to loosen control of the training process. It will also give them a range of new (to them) training techniques to add to their armoury which will encourage participation. Together these outcomes of a TOT course will result in a more relaxed and confident trainer, who is able to guide group discussions, exercises and teamwork that promote better and longer lasting learning by participants.

WHAT TO INCLUDE IN A TRAINING PROGRAMME

So much for how training is conducted, and now on to the topics to be covered. Too frequently a training course only addresses participants' wishes to learn how to make a product. If someone had given me a dollar every time I have been asked 'please teach me how to make mango jam' I would be very wealthy by now!

In the selection of products le.. include, a trainer needs to have an awareness of the local market for different foods and advise trainees that for some there is either little demand or very high levels in competition - either of which would make their business more difficult than for other products. Ideally, the products selected for a training programme should all be potentially capable of supporting a successful small business. Where data on demand is not readily available, the trainers should conduct their own preliminary market surveys to gain an idea about which products are likely to be successful.

Similarly on the training course itself, many trainers only include the production technology and quality control? ignoring the commercial realities of production and the socio-economic environment in which an entrepreneur will operate. While it is true that a high quality product is preferable to a poor quality food, there should also be a detailed understanding of how to sell the product, who will buy it and how much will they pay for it - in other words market research should be the starting point when considering which food to include in a training programme.

If there is a little demand for a food or if other producers are already successfully meeting the demand, it is in my opinion, irresponsible for trainers to raise the expectations of participants by teaching them how to make the food and implying that they could operate successfully. A more likely result is that at best, new producers will put their training into practice, invest in their business and fail, losing their money in the process. At worst, new producers will copy existing products, but then make them to a lower quality to reduce costs and compete more effectively. This causes customers to mistrust the entire range of the particular product, including the original successful small businesses and stop buying it. Then the whole market collapses, causing original producers and newcomers to fail together.

So a training course should give equal, if not more attention, to business aspects such as market research, production planning, marketing/selling, agreements with suppliers and retailers, financial management, preparation of feasibility studies etc. In my experience, this may take up to 6070 per cent of a course, with only 30-40 per cent devoted to the technical issues. Additionally, the business areas are not only the ones that participants require greatest assistance with, but they are also the ones the food scientists and technologists have least competence in dealing with. In such situations it is necessary to employ a business trainer who has experience of small enterprise development, to work alongside technical trainers.

Market research should be the starting point when considering which food to include in a training programme.

TRAINING FACILITIES AND EQUIPMENT

Last but not least, the training environment is particularly important when conducting courses for small-scale food processors. Here there is a dilemma that many trainers fail to recognize. On the one side there is a need for production facilities to he clean and hygienic - both to maintain the quality of the products, and in many countries to meet health and hygiene legislation. However, the route used by many trainers to achieve this is to go to a university or similar institution and hire their pilot plant for the course. Alternatively, those organizations that are well funded may import shiny new stainless steel processing equipment and put it into a sparkling new tiled room, complete with air conditioning and hot running water.

While this will meet the legislative requirements, it will also frighten any small producer who sets foot into the training room. The obvious reaction of a trainee would be 'if this is what is needed to do food processing, how could I ever afford the investment to get started' or more likely these people do not understand the situation that I am in, so how is this training going to he relevant to me'. Expensive and inappropriate facilities and equipment therefore have the effect of making trainees distrust their trainer's understanding of their needs and make the trainers, job more difficult before they have even started.

A compromise is possible in which a building has the correct design and construction to meet legal requirements without making it so expensive that it is beyond the reach of participants (including for example, drainage channels built into the floor, sloping window sills and a sealed ceiling to prevent dust accumulations, sealed concrete walls and floors, walls painted instead of tiles etc.). A Technical Brief on the subject of appropriate building design for food processing is available from Intermediate Technology and this is equally suitable to the design of an appropriate food processing training room. An alternative, when funds are not available to construct a training room, is to pay a local entrepreneur to use the production facilities for the training course. In this case, the entrepreneur will require assurance that you are not training competitors, but this should be possible if trainees come from another district, as few small businesses have widespread distribution of their products to distant markets.

Similar considerations apply to the selection of equipment. It is usually possible to import small-scale equipment from industrialized countries and in many cases this has desirable benefits in demonstrating design concepts or meeting a need when no locally manufactured alternatives are available. However, a more sustainable approach is to contract local metal fabrication workshops to build items of equipment for the courses, providing designs and photographs where possible to assist them. This not only gives the workshops some welcome promotion for their products, but makes available more affordable and repairable equipment for food processing entrepreneurs when they begin production. This approach also stimulates the local engineering workshop sector and diversifies the benefits of training.

In Uganda and Ghana, Midway has taken this a stage further and now holds courses for engineers in 'Design and Manufacture of Food Processing Equipment' alongside food processing courses, thus putting manufacturers and potential customers directly in touch with each other. This concept of 'Sustainable Alliances' between different sub-sectors is a central theme of Midway's approach to development and will feature in a forthcoming article in Food Chain.

There is much more that can be said about good training, including both the essential requirement for follow-up and refresher training and the need for participants to practice their new skills/knowledge and make mistakes without financial risk within the safe environment of a training programme. But in conclusion to this article, we can note that there is much bad practice in food processing training, caused in particular by trainers failing to take account of the needs of participants and the focus on traditional teaching methods that maintain their position of authority and control. To be successful and produce sustainable benefits for participants, training courses should carefully identify their training needs and then design courses and facilities that are appropriate to meet those needs. is never a simple matter and I am wary of those who say that training is easy... it often indicates that they are not doing a good job!

Dr Fellows is a director of Midway Technology and can be contacted via their office at St Oswalds Barn, Clifford, Hay on Wye, Hereford, UK

A compromise is possible in which a building has the correct design and construction to meet legal requirements without making it so expensive that it is beyond the reach of participants

 

 

Booklines

Hazard analysis critical control point evaluations

A guide to identifying hazards and assessing risks associated with food preparation and storage. Frank L Bryan Published by the World Health Organization. ISBN 92 4 154433 3 Price Sw fr 15- price in developing countries Sw fr 10.50.

The hazard analysis critical control point (HACCP) system is a relatively new approach to the prevention and control of foodborne diseases, which seeks to identify the hazards associated with the various stages of food production and preparation, assess the related risks, and determine the operations where control procedures will be effective. This publication provides guidance on the application of the system to the preparation and storage of food in homes, food service establishments, cottage industries, and street markets. Drawing on approaches used by a number of food-processing companies, it outlines the principles that underlie the HACCP concept, as well as providing practical advice on how to conduct an analysis, and numerous examples of critical control points and monitoring procedures for common foods and processing operations. This guide is intended for use by public health personnel with some training in food microbiology and technology, who are concerned with the prevention of foodborne disease. It will assist in the planning of food safety and health education activities focused on the types of food commonly prepared and eaten by the local population.

DEHYDRATED VEGETABLES and DRIED/DEHYDRATED TROPICAL FRUIT -

SURVEYS OF MAJOR MARKETS

1993 & 1994. International Trade Centre, Palais de Nations, 1211 Geneva 10, Switzerland. ISBN 92-913 7-005-8

These two books should be on the bookshelf of any company or organization involved in, or contemplating the production of dehydrated fruits and vegetables. Each book surveys global markets and then examines major importing countries in more detail. A wealth of useful data including technical specifications of leading buyers, indicative prices, import regulations and lists of useful contacts in major importing countries is included. It is understood that these publications may be free of charge to certain developing countries.

PRODUCTION, HANDLING AND PROCESSING OF NUTMEG AND MACE AND THEIR CULINARY USES

Guido B Marcelle, FAO Regional Office for Latin America and the Caribbean. 1995. 95 pages.

A very well presented book with more than 20 colour photographs, that examines nutmeg from its botany through to utilization in cooking. The central section on post-havest handling and treatment is most likely to be of greatest interest to Food Chain readers. This describes very clearly the post-harvest system and examines in some detail the classes, or grades, of products. The final section of the book lists eleven products in which nutmeg and mace are used. Having worked with these products, I welcome this book which so clearly brings together information that was previously spread in a variety of publications and research reports

TRADITIONAL BEANCURD MANUFACTURE

Natasha J Johnson, Intermediate Technology, 1994. 40 pages

This booklet reviews the wide range of beancurd varieties available, the principles used in their manufacture by traditional methods, and those methods that have potential for large-scale manufacture. We have a number of copies of this comprehensive booklet available free to Food Chain readers. Please write to Ann Watts.

 

 

Principles of food dehydration

It is important to appreciate that drying foods by traditional methods is very area specific, and these methods have evolved over many years to take account of the local climate.

We have heard from a number of readers that they find Food Chain articles very useful for teaching and training purposes. Therefore we have decided to introduce a training element to Food Chain, which, while aimed particularly at trainers, should also be of interest to those involved in food drying.

The preservation of foods by drying is the oldest and most common method used by mankind. Usually foods are dried by exposing them to the heat of the sun either on the ground on mats or trays raised off the ground, or by hanging them under the eaves of huts and houses. In very damp humid areas such as the Amazon, it is necessary to use also the heat of cooking fires in order to fully dry the food. In these cases preservation is assisted by the preservative action of chemicals in the smoke.

It is important to appreciate that drying foods by traditional methods is very area specific, and these methods have evolved over many years to take account of the local climate, commodities available and social habits of the inhabitants. A wide range of foods are traditionally preserved including fruits, vegetables, nuts, herbs, spices, medicinal plants, milk products, meat and fish. While the prime objective is to preserve excess produce for times of need, the reduction in weight is also of prime importance for nomadic peoples.

WHY PRESERVE FOODS BY DRYING?

Nowadays many foods are dried not solely for food security, but for commercial reasons, and this change has far reaching implications. The most important is that in many cases the foods to be processed are not selected for being in balance with the local ecology and climate, but for their market potential. This means, for example, that fruits which grow well in a humid tropical area have to be dried under conditions in which traditional sun drying simply will not work. Therefore new technologies have to be developed to make the drying process more independent of local climates, in other words -artificial dryers are needed.

Other considerations of commercial dehydration are profitability, buyers' demands for quality, and packaging for a long shelf life.

When drying foods commercially the most important consideration is the value added (per unit weight) by processing which must be sufficient to cover all the costs involved. These include:

• losses of rejected material

• labour

• fuel

• depreciation of equipment

• packaging

• rent, taxes and other statutory obligations.

Finally there must be a profit for the enterprise.

Foods can be divided into three broad groups based on the value added through processing by drying. In the case of cereals, legumes and root crops, very little value is added per ton processed. For example, a ton of rice that is well dried in an artificial dryer will be worth very little more than a ton which has been sun dried on mats at the farm. With such crops drying can only be economic either at a very large scale in silos, or in climates in which sun drying is totally impossible due to rain or high humidity.

More value per unit weight is added to foods such as vegetables, fruits and fish; and considerably more to high value crops such as spices, herbs, medicinal plants and nuts. These are the products that are most suitable for small and medium scale enterprises, as sufficient value can be added from processing at small scale to cover costs and make a profit.

HOW ARE FOODS PRESERVED BY DRYING?

The majority of fresh foods contain between 70 and 95 per cent moisture and it is this water that allows micro-organisms such as moulds, yeasts and bacteria to multiply, causing rot and spoilage. If the moisture content is reduced to between 5 and 25 per cent (depending on the type of food), there is insufficient moisture to support micro-biological growth and the food is preserved. The micro-organisms however, are not dead, they simply remain dormant and should the moisture content rise by absorbing water from the atmosphere after drying they will start to multiply again. Hence the need for good protection by packaging.

As mentioned above, the necessary reduction of the moisture content to preserve a given food is wide, ranging up to 25 per cent. The reason for this is that it is not the actual amount of moisture in a food that is critical hut the amount of the total moisture that is available for microbiological growth. Some food components, in particular sugars and salt, are able to chemically hind water making it unavailable to micro-organisms and this is the reason that fish and meat is usually salted, and some fruits are sugared prior to drying.

Some foods, in particular those containing fats and oils, deteriorate through the action of enzymes (naturally occurring components of living matter) that give rise to rancidity, colour loss and flavour changes. A reduction in moisture content slows down the rate of such enzymatic actions and so prolongs the shelf life of the commodity.

The micro-organisms however, are not dead, they simply remain dormant and should the moisture content rise by absorbing water from the atmosphere after drying, they will start to multiply again.

DRYING THEORY

The process of dehydration involves the removal of water by evaporation from the surface of the food to the surrounding air and the rate of drying depends on:

• the size of the food particle and its surface area. Moisture is lost from the surface of the food particle, so the smaller its size the less is the distance that the water has to move to the surface.

• the nature of the food. Products that contain sugars for example, tend to bind moisture which results in slow drying rates. Fibrous leafy materials dry very quickly, whilst starchy materials dry more slowly and fruits containing sugars even more slowly.

• the condition of the air used. Dry air is able to absorb more moisture than humid, damp air.

• the quantity of air passing over the food. A given volume of air can absorb a given quantity of moisture, therefore the greater the volume of air passing over the food, the greater the removal of moisture

• case hardening is a phenomena which occurs mainly in starchy foods when the surface dries relatively rapidly and forms a barrier to moisture moving from the interior of the food particle to (and through) the food surface. Case hardening can dramatically reduce drying rates.

• the over-all geometry of the drying system. Efficient removal of moisture depends upon efficient contact between the air and the material being dried.

Table 1. Kg of water that can theoretically be removed per kg of air.

Temperature

RH%

Water removed (Kg)

20

90

0.6

30

50

7.0

40

28

14.5

50

1 5

24.0

PROPERTIES OF AIR

Air contains water vapour, the amount present being expressed as its humidity which can he expressed in two ways Relative humidity and Absolute humidity.

Relative humidity (RH%) is the most commonly used description. Absolutely dry air has an RH of 0% while air that is saturated with moisture has an RH of 100%. The amount of moisture that air can absorb is very temperature dependent and Table 1 shows the effect of heating air with an RH of 90% at 29°C on the RH % and the amount of water that the air can absorb to be saturated (that is reach 100% RH). Table 1 clearly demonstrates that a small amount of heating of the air has a dramatic influence on the quantity of moisture it is capable of absorbing from food.

Absolute humidity is the actual weight of water vapour present in a given air. It is usually expressed in kgs of water per kg of dry air. While the term is less commonly used, an understanding of absolute humidity is essential when undertaking theoretical drying calculations such as designing a drier. Absolute humidity does not change with temperature because no water is added or lost by simply heating air.

This article was written by Barrie Axtell, Technical Editor of Food Chain and a director of Midway Technology.

 

 

Simple methods of quality assurance

In the third of our regular features following on from tests that can be made on flours, we look at more simple methods for use in a small bakery. In this issue a further two methods for assessing starch gelatinisation quality and water absorption are described. The author, Dr Peter Fellows, would like to acknowledge the information contained in a recent FAO Publication: Quality Assurance for Rural Food Industries, FAO Technical Bulletin No 117, available from FAO Publications, FAO, Rome.

STARCH GELATINISATION MEASUREMENT (MODIFIED 'FALLING NUMBER' METHOD)


STARCH GELATINISATION MEASUREMENT

The ability of starch to gelatine (to thicken when heated with water) is a major concern especially when preparing batters for cakes, as this will determine the structure and volume of the cake. This simple method can he routinely used in a bakery.

1. 100g of flour is mixed with 900g of hot water in a pot

2. The pot is heated until the flour mixture has gelatinised.

3. The mixture is poured into 1 litre measuring vessel such as a graduated glass cylinder.

4. The measuring vessel is stood in hot water.

5. A steel ball is dropped into the mixture and the time to drop 200ml recorded.

6. The time (in seconds) is compared against the standard batch.

It should he noted that this method relies on comparison of results between different batches using the same measuring cylinder. It cannot be used to compare results from different cylinders unless they are identical.

WATER ABSORPTION MEASUREMENT (FLOUR)

The amount of water absorbed by flour is one of the most important factors affecting the structure and texture of all baked goods, including breads, biscuits and cakes. In this method a burette is required to accurately measure added water. This equipment can usually be obtained from a scientific suppliers in the capital city, hut could also be made locally by carefully calibrating a glass tube to indicate exactly the volume of water contained (see Figure).

1. 100g of flour is weighed into a small mixer or mixed by hand.

2. Water is slowly added from a burette until a standard dough is made. This is judged by the processor by adding water until it feels right.

3. The amount of water added is recorded.

New batches of flour are tested alongside the existing material. This can be used as a comparative test to indicate a wrong grade of flour.

 

 

Research notes

CONTROL OF MALARIA WITH MARIGOLD

In many countries malaria is increasing with a growing resistance to drugs that control the disease and the conventional control measures involving insecticides is cause for environmental concern. Researchers at the Institute of Nuclear Medicine and Allied Science (INMAS) in India have developed an ecologically friendly, biodegradable insecticide from marigold flowers which contains compounds against the larvae of not only Anopheles species but also Cutex the agent of Japanese encephalitis.

The insecticide is made by crushing marigold petals and roots in alcohol. As the alcohol evaporates it yields a yellow extract containing alphateriophene and erythrosin-3. The agents are only active against larvae in the presence of sunlight. Trials have shown a 20 per cent mortality in four days for Anopheles and 100 per cent activity against Culex in three days. The researchers have studied the mechanism of control and claim the biodegradable extract does not pose a health hazard to people. With the increasing trend against the use of toxic, non biodegradable chemicals, work of this nature requires greater attention and we believe offers considerable potential for developing countries - many of which have a still untapped pool of big-diversity.

 

 

Food preservation by the Turkana people.

This article was written by Jeremiah Etheri who works within the Rural Agriculture and Pastoral Programme of Intermediate Technology, Kenya.

The Turkana district of north western Kenya is situated in arid and semi-arid lands with a very fragile economy and environment. Its population, the Turkana, are by tradition pastoralists, moving with their cattle across large areas. While the total population of the 75,000 km² is only some 400,000 the district has been experiencing a decline in per capita food production due to increasing population pressure on land and water resources. There is also a shift from the predominantly pastoral life to a more settled agro-pastoral economy which puts more pressure on the fragile environment and results in further degradation of resources. Against this deteriorating background there is a need for increased regional self sufficiency on foods and the promotion of efficient use of available resources in order to have sustainable development of the district. IT Kenya is thus studying food preservation methods used by the Turkana to provide base line data on the current situation.

In African societies women are responsible for the handling of foods and other related tasks. This is even more so in pastoral societies where men would be ridiculed if seen to be interfering in so called women's tasks. Amongst the Turkana the women perform all domestic tasks including milking, processing wild fruits, shearing animals, collecting firewood fetching water and cooking. Other tasks, such as long-distance herding, are assigned to men and children. The pastoral society gives women recognition for maintaining food storage and preservation technologies. They are seen as 'custodians and experts of household food technologies, having the required skills, knowledge and strength to perform the tasks involved. While food preservation and preparation takes up a lot of women's time it has to be done alongside other work.

The processing and storage of all surplus food is vital for the survival of the Turkana people during the dry season and droughts. Food stored includes milk, meat, blood, fat, honey, wild fruits, tubers and cereals. The technologies used by the women to do this require study and scientifically recognition so that they can, where possible, he developed to the advantage of both women and the Turkana society.

MILK PRESERVATION


MILK PRESERVATION

Milk is a very important staple food for the Turkana, and each adult consumes two to four litres per day during the rainy season when the production is highest, (though this may well be considerably less in poorer families who have fewer animals -in which case the milk production is often reserved for children). Consumption is also less during the dry season. The Turkana have learnt, from hard times and famine, the importance of preserving surplus milk, for future use. A number of preservation methods are used but it is considered that there are opportunities to improve the techniques used. Fresh milk, either straight from the animal or boiled and cooled, and often mixed with the blood from cattle is an important part of the Turkana diet.

The Turkana record that they use 47 plants for food and 62 for medicinal purposes, and the gathering of wild fruits is an important food security strategy.

Commonly the milk is allowed to ferment or sour naturally over a period of four days or more, during which time it clots, the solid matter can then be separated from the watery whey. This is used to make a porridge, mixed with blood as a drink or mixed with tamarind to make a type of 'lemonade'. The Turkana people also churn the fermented milk to make butter. The milk is placed in a gourd suspended by a rope from the door frame of their hut. It is then shaken to and fro until the butter separates. The mixture is then poured into a wooden bowl and the butter is separated using a wooden spoon. Finally the butter may be heated, to remove the traces of water, so producing butter oil which is used for cooking, as a cosmetic and for preserving leather and wood. Butter oil keeps longer than the butter.

The Turkana also make milk powder by sun drying the clotted fermented milk on flat rocks or hides. This only takes two or three days under the 38°C conditions. The resulting milk powder (called edodo), containing cream, will have a high fat content. Alternatively, the skimmed milk remaining after making butter, is allowed to ferment for a further three to five days after which the suspended solids formed are sun dried. The resultant milk powder from this second method results in the production of a skimmed milk powder, without cream, with only traces of fat. Milk powder, which has a longer storage life than liquid milk, is of a high food value per unit weight, weighs less than liquid milk and is therefore ideal for a people who have to travel with their animals.

MEAT PRESERVATION

Meat is one of the most precious food items in the Turkana diet and even the poorest families needs are met by the occasional slaughter of a sheep or goat. In addition, there is communal sharing of the meat with each homestead contributing in turns. No ceremony is complete without meat on the menu.

The pastoral Turkana preserve meat in several ways:

• In long thin strips which are hung up and sun dried in about a week. In some cases salt is added to speed the drying process.

• In tiny one inch ball-shaped pieces which are deep fried to a golden colour; after which they are either sun dried or stored in a wooden container under oil. Any cooking oil left over is also stored.

• As a pounded or minced meat which is sun dried. This product may also be stored under oil (which is stated to increase its life), or mixed with seeds or cereals such as maize or sorghum.

PRESERVATION OF FRUITS AND VEGETABLES

The Turkana record that they use 47 plants for food and 62 for medicinal purposes, and the gathering of wild fruits is an important food security strategy. Though there are many types of fruit trees in Turkana, we will look at two particularly important plants Edapal (Dobera glabra) and Engal (Doum palm). Edapal grows well along streams but is to be found all over the plains. It is one of the few plants that remains green during the dry season. The tree fruits twice a year and the Turkana utilize the seeds or beans of the fruit. After harvesting, the beans are threshed to remove the green outer covering. The resulting white beans are boiled, often with a little wood ash which helps to soften the white seed coat and makes its removal easier. Other seed bearing fruits receive similar treatment but may require prolonged boiling to remove bitter tastes. Edome (Cordia sinensis) for example, requires four hours boiling and Edung (Boscia coriacacea) up to ten hours. It is interesting to note that the Turkana only partially de-bitter these seeds by boiling as they find fully de-bittered seeds suffer greater losses in storage due to insects. After boiling the 'beans' are sun dried on hides and then stored in leather sacks. They can be transported as the Turkana move their stock. Few communities, due to their nomadic life, use grain stores.


PRESERVATION OF FRUITS AND VEGETABLES

The Doum palm is found along streams and around lakes. The fruits are harvested each year and the yellow, fleshy internal part of the seeds is crushed to a powder and dried for storage. It is an important component of the diet and is used mixed with blood or oil, mixed with milk, as a sweetener in cereal gruels or fermented to a wine. It is reported that eating too much engol causes diarrhoea, this is probably why it is always mixed with other foods.

While today many of these traditional preservation methods are still used by the Turkana, their application is in decline because of a reduction of livestock due to droughts, increasing population, and the increasing access to alternative foods. For this reason we feel it is important to study and document Turkana methods before the knowledge is lost.

 

 

Ayib (traditional cheese)

PRODUCT DESCRIPTION

Ayib is an unfermented 'cheese' made by coagulating milk solids from buttermilk. It is used as a component of traditional dishes such as Kitifo and Doro wet (Ethiopian minced and raw meat, with chicken sauce). It is white in appearance and similar to European cottage cheese, but more sour in taste and with a pronounced cheese flavour.

PRINCIPLES OF PRESERVATION AND PROCESSING

Bacteria in the milk are destroyed by heating and recontamination is limited by the higher solids content after coagulation of milk solids. However, the product has a shelf-life of one day unless refrigerated.

HYGIENE

The product must be handled with good, sanitary practices as even slight contamination can cause off-flavours and make it unfit for consumption. The product must be sold or consumed within 24 hours if refrigeration is not available.

The main hygienic requirements are:

• Thoroughly clean and sterilize all equipment and utensils before and after processing.

• Strict enforcement of personal hygiene measures.

RAW MATERIAL

Aryera is a low acid product that is very susceptible to spoilage and transfer of pathogenic bacteria to consumers.

PROCESS CONTROL

The main control points are the temperature and time involved in the heating of aryera, which determine the product quantity and yield: overheating results in loss of quantity and off-flavours whereas underheating lowers the yield and may risk passing on food poisoning bacteria to customers.

PACKAGING AND STORAGE

During packaging the most important quality control check is to ensure that filling equipment and bags are not contaminated.

EQUIPMENT

No special equipment required.


Stages