Food processing as a scientific and technological activity covers a broader area than food preparation and cooking. It involves the application of scientific principles to slow down the natural processes of food decay caused by micro-organisms, enzymes in the food or environmental factors such as heat, moisture and sunlight - and so preserve the food. Much of this knowledge is known traditionally and put into practice by experience and information handed down through the generations. In most developing countries food processing is also a method of generating employment and family incomes. Under these circumstances, producers must compete with others in the same country and with imported products. With some important exceptions, traditional processing methods produce foods that are usually inadequate to compete with the 'newer' products. This is particularly important with respect to packaging and presentation of the processed foods.
One purpose of this book is to document improved ways of processing fruits and vegetables at a scale that is appropriate for families and other groups of people to earn a daily income. This also involves methods of business planning, work organization, marketing and quality assurance that are likely to be unfamiliar to traditional processors, but which are essential to ensure successful and profitable production.
There are also important reasons for improving food processing that is done in the home to meet family needs and the book is therefore divided into two Parts: first a description of some of the problems and issues that face people involved in home processing, together with some suggested solutions; and secondly a more detailed description of the various aspects that are involved in setting up a small food processing enterprise. In general terms, the benefits of small scale fruit and vegetable processing for people in developing countries can be broadly stated as follows:
· raw materials are readily available (often in surplus)· most technologies are available, accessible and affordable at scales that are suitable for small operations
· equipment can often be manufactured locally, creating additional employment
· the products, if chosen correctly, have a widespread demand
· compared to some other technologies, small-scale fruit and vegetable processing is particularly suitable for women
· most processes have few environmental impacts.
However, the selection of suitable products for small scale manufacture and the processes chosen to make them, require very careful consideration. It is not sufficient to assume, as many 'advisers' do, that simply because there is a surplus of a raw material each year, a viable fruit and vegetable processing venture can be created to use up the excess. There must be a demand for the processed food which is clearly identified before a business is set up. Otherwise the most likely result is to produce a processed commodity that no-one wants to buy with substantial financial losses to those involved.
There are numerous examples of misguided development projects that have resulted from a desire to prevent piles of rotting fruit from accumulating each season by processing them. Instead, the result has been shelves of more expensive, rotting processed foods that no-one wants to eat.
In general the types of products that are suitable for small scale production are those for which there is a high demand, and a higher value can be added by processing. Typically fruits and vegetables have a low price when in their raw state, but can be processed into a range of snackfoods, dried foods, juices, pickles, chutneys etc., which have a considerably higher value.
The high added-value means that the amount of food that must be processed to earn a reasonable income is relatively small. Hence the size and type of equipment required to operate at this scale can kept to levels that are affordable to most aspiring entrepreneurs.
A further consideration that applies to both home processing and commercial production is the safety of the fruit and vegetable products that are produced. Although there are many similarities between fruit and vegetables, it is important to note the following difference: most fruits are acidic and this acidity controls the type of micro-organisms that are able to grow in the processed products. Food poisoning bacteria cannot grow in the acidic conditions, but moulds and yeasts are able to grow and produce obvious visible spoilage which stops consumers from eating the food. Even if a contaminated fruit product is eaten, yeasts and moulds rarely cause severe food poisoning.
Vegetables however, are generally less acidic than fruits and a wider range of micro-organisms are able to grow in vegetable products, including food poisoning bacteria. This is particularly dangerous when certain types of bacteria release poisons (or 'toxins') into the food, but do not produce obvious signs of spoilage. Consumers may therefore be unaware of the contaminating bacteria and eat the poisoned food. Careful control of processing conditions and attention to hygiene are therefore essential when processing less acidic vegetable products.
Dried fruits and vegetables do not allow micro-organisms to grow, provided that drying is carried out correctly and the food is kept dry. However, if the food is heavily contaminated before drying, or if it is allowed to get damp during storage, these micro-organisms can grow again before the food is eaten. A summary of the effects of different processing methods on micro-organisms is shown in Table 1.
In addition to the actions of micro-organisms, naturally occurring enzymes rapidly change the colour, flavour and texture of fruits and vegetables after harvest. In general, these changes, due to both micro-organisms and enzymes, produce a characteristically short shelf life and rapid processing after harvest is therefore necessary.
Details of the points in a process where control is needed to ensure food safety or to maintain food quality are given in the descriptions of each production process in Part 2 and a summary of good food handling practices is given in Appendix I.
In many countries, vegetables and fruits are among the most accessible raw materials for processing. Traditionally, cultivation of vegetables in small garden plots has been common in most tropical regions and the planting of fruit trees around the house or compound has provided shade and wood as well as fruit.
These activities are being expanded and promoted in a large number of both home gardening programmes to improve household nutrition and in orchard planting and regeneration programmes designed to address environmental concerns such as soil erosion and also to improve fruit quality and varieties.
These programmes, together with an increasing awareness of the value of processing for improved food security and income generation, has resulted in fruit and vegetable processing being seen by many development agencies and government institutions as an important method to improve the livelihoods of both rural and urban populations.
However, to be successful these initiatives should from the outset have clearly defined objectives concerning the expected benefits of processing. These may include direct benefits to participating groups or individuals, such as:
· Improved storage of fresh produce without excessive losses· improved nutritional status through consumption of fruits and vegetables for a larger part of the year
· increased income for sale of processed fruits and vegetables
· preservation of seasonal gluts which would otherwise be wasted.
There may also be improved backward linkages to farmers and suppliers (especially in integrated development programmes) as a result of increased demand for raw materials by processors. This may:
· improve the amount, quality and varieties of fruits and vegetables that are grown· improve the rural environment as a result of planting fruits and vegetables. Such improvements may include soil regeneration and rainwater retention due to orchard or vegetable planting
· improve incomes to farmers from higher sales of raw materials to processors, or secure supply contracts that reduce farmers' dependency on seasonal price fluctuations
· increase demand for equipment, packaging materials and ingredients which stimulates development of associated supplier industries and creates strategic alliances between different manufacturing sectors.
Table 1. - Effects of different types of food processing on micro-organisms
|
Processing method |
Principle of preservation and effect on micro-organisms |
|
Preparation methods: |
No preservative action. No destruction of micro-organisms (some processes such as chopping or mixing may actually promote growth of micro-organisms by making the food more available for them to grow on) |
|
Heating: |
Heat kills all types of micro-organisms and destroys the ability of naturally occurring enzymes to act. |
|
Removing heat: |
These processes slow down the rate at which micro-organisms can grow and enzymes can act, but processing does not destroy them. Freezing also turns water to ice so that it is not available for micro-organisms to use. Freezing therefore has a greater preservative effect than chilling. |
|
Removing water: |
Water is needed for micro-organisms to grow and for enzymes to act and drying therefore prevents this. However, many types of micro-organisms are not killed by lack of water and they can grow again when food is dehydrated. |
|
Chemical: |
Micro-organisms are killed by high concentrations of alcohol, salt or sugar. |
* Water is removed or made unavailable, which contributes to the preservative effect.(Note: the use of low temperature processing is not considered in this book due to the high capital costs of equipment and the need for refrigerated distribution and storage, which is both expensive and not widely available in most developing countries).
There may also be benefits from improved forward linkages between processors and retailers/customers including:
· lower cost and increased availability of locally processed foods
· improved quality through greater competition between producers
· increased diversification in the varieties of processed food that are available in the diet
· improved relationships and trust between processors, retailers and customers.
When sufficient numbers of new processors are operating there may also be an effect on the national economy due to reductions in the use of foreign exchange by substitution of imported ingredients or finished products.
When promoting food processing, each programme should therefore have a clearly defined set of objectives. These can be broadly characterised as:
a) those that are likely to result in improved nutritional status or better food security; andb) those that are likely to improve individual incomes or national economies.
Different approaches are needed when promoting processing to increase food security or nutritional status, compared to those that are used to establish or support small processing enterprises for income generation. The different objectives of a programme should therefore be clearly identified at the outset and appropriate methodologies developed to address each one. Although details of such methodologies are beyond the scope of this book, a summary of issues that should be addressed to meet differing objectives is shown in Table 2.
In this book, aspects of improved nutrition and food security are described in Part 1 and those concerned with processing for income generation are included in Part 2.
Table 2. - Issues to consider when addressing different objectives of food processing
|
Issues that affect food security and nutritional improvement programmes |
Issues that affect enterprise development programmes |
|
· Nutrition education |
· Market awareness and consumer preferences |
|
· Health and hygiene training |
· Marketing strategies, promotion and packaging |
|
· Development of groups |
· Methods of financial control |
|
· Improved communication |
· Developing trusting relationships with suppliers and retailers |
|
· Confidence building |
· Quality assurance |
|
· Agricultural skills training |
· Hygiene and sanitation for production |
|
· Credit support systems |
· Food legislation |
|
· Development of producer cooperatives or other farmer associations |
· Taxation and business legislation |
|
· Improvements to equipment and tools |
· Training in management and business planning |
|
· Improved transport and infrastructure |
· Finance and credit suppliers |
|
· Seed banks and other sources of agricultural inputs |
· Staff training in production technologies |
|
|
· Suppliers of specialist equipment and ingredients |
