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Basic facts about food preparation and processing

People process foods every day when preparing meals to feed their families. However, the term "food processing" is broader than preparing and cooking foods. It involves applying scientific and technological principles to preserve foods by slowing down or stopping the natural processes of decay. It also allows changes to the eating quality of foods to be made in a predictable and controlled way. Food processing uses the creative potential of the processor to change basic raw materials into a range of tasty attractive products that provide interesting variety in the diets of consumers.

Food preparation and processing can be defined as "any change that is made to a food to alter its eating quality or shelf life".

All food manufacturers should make safe foods so that consumers are not at risk. This is not only microbiological risks, but also glass splinters, pesticides or other harmful materials that can get into the food and lower its quality. Consumers consider eating quality as the main factor when buying foods, and a food should fit in with traditional eating habits and cultural expectations of texture, flavour, taste colour and appearance. For some foods, nutritional quality (e.g. protein content, vitamins and minerals, etc.) is an important consideration. Product quality is affected by the raw materials, the processing conditions and the storage and handling that a food is subjected to after processing. Food processors should understand the composition of their foods because it enables them to predict the changes that take place during processing, the expected shelf life of the product and the types of microorganisms that can grow in it. This information is used to prevent food spoilage or food poisoning. Details of the composition of raw materials or products can be obtained from university food science departments, bureaux of standards or food research institutes.

Types of processing

Without processing, as much as 50 to 60 percent of fresh food can be lost between harvest and consumption. This may be due to inadequate storage facilities, which allow micro-organisms or pests to spoil the stored food. Improved storage can greatly reduce these losses (Clark, 2002). Processing methods that are suitable for village scale processing can be grouped into six categories (Table 1). A number of other preparation methods (such as mixing, coating with batter, grinding, cutting, etc.) alter the eating quality of foods, but do not preserve them. It is important to note that the production of most food processed foods uses more than one of the categories in Table 1. For example, jam making involves heating, removing water, increasing the levels of acidity and sugar, and packaging. Smoking fish or meat involves heating, removing water and coating the surface with preservative smoke chemicals.

Effect of processing on the quality of foods

In addition to preserving foods, secondary processing alters their eating quality. (See Glossary in Annex C). A good example is cereal grains, where primary processing by drying and milling produces flour, which remains inedible. Secondary processing is used to produce a wide range of bakery products, snack foods, beers and porridges, each having an attractive flavour, texture and/or colour. Eating quality is the main influence on whether customers buy a product. Foods that have an attractive appearance or colour are more likely to sell well and at a higher price. It is therefore in the interests of processing businesses to find out what it is that consumers like about a product using market assessments and ensure that the products meet their requirements. This is described below.

Scales of operation

When operating as a business, food processing can take place at any scale from a single person upwards (Table 2). The focus of this booklet is on the smaller scales of operation from "home-scale" to "small-scale".

Home-scale processing

Foods that are intended for household consumption are usually processed by individual families or small groups of people working together. Many of the world's multinational food conglomerates started from a single person or family working from home (Table 3). In developing countries, home-scale processors aim to generate extra income to meet family needs such as clothing or school fees. Where this is successful, many later expand production and develop first into a micro- or small-scale business (Case study 1), and later into larger scale operations.

Characteristically, home-scale processors cannot afford specialized food processing equipment and rely on domestic utensils, such as cooking pans and stoves for their production.

TABLE 1 Types of village food processing

Category of process

Examples of types of processes

Heating to destroy enzymes and micro- organisms.

Boiling, blanching, roasting, grilling, pasteurization, baking, smoking

Removing water from the food

Drying, concentrating by boiling, filtering, pressing

Removing heat from the food

Cooling, chilling, freezing

Increasing acidity of foods

Fermentation, adding citric acid or vinegar

Using chemicals to prevent enzyme and microbial activity

Salting, syruping, smoking, adding chemical preservatives such as sodium metabisulphite or sodium benzoate

Excluding air, light, moisture, micro-organisms and pests


TABLE 2 Scales of commercial food processing

Scale of operation


Home- (or household-) scale

No employees, little or no capital investment

Micro- (or cottage-) scale

Less than 5 employees, capital investment less than US$1 000


5-15 employees, capital investment US$1 000-US$50 000


16-50 employees, capital investment US$50 000-US$1 000 000


More than 50 employees, capital investment over US$1 000 000

Adapted from Trager, 1996

They may work part-time as the need for money arises and use part of the house, or an outbuilding for processing. However, in many situations the lack of dedicated production facilities means that there is a risk of contamination and product quality may be variable. This may reduce the value of the processed foods and the potential family income. A role of extension agents and training programmes is to upgrade facilities and hygiene, to introduce simple quality assurance techniques and improved packaging, to enable products to compete more effectively with those from larger processors.

Where families generate sufficient income from sales, some choose to invest in specialist equipment (such as a bakery oven, or a press for dewatering cassava or making cooking oil). In most cases, such equipment can be made by a competent local carpenter, bricklayer or blacksmith. This allows home-scale businesses to expand and become micro- or smallscale enterprises.

Micro-scale processing

Whereas home processors may sell their products to neighbours or in village marketplaces, the move up to micro-scale processing requires additional skills and confidence to compete with other processors and to negotiate with professional buyers, such as retailers or middlemen. Similarly, although the quality of their products may be suitable for rural consumers, it may not be sufficient to compete with products from larger companies in other markets. To successfully expand to micro-scale production, village processors need technical skills to make consistently high quality products, and financial and marketing skills to make the business grow and become successful. They may require assistance to gain these skills and confidence, and short training programmes or technical extension workers can help them to establish improved production methods, quality assurance and selling techniques.

Small-scale processing

The expansion to a small-scale processing operation requires additional investment to produce larger amounts of product in a dedicated production room. It is likely to require specialist equipment that is either made by a metal workshop in a nearby town or imported, because most rural blacksmiths do not have the necessary skills, equipment or materials to make such equipment. At this level of production, village processors are likely to be in competition with other small-scale businesses, larger companies and imported products. They need to develop attractive packaging, quality assurance techniques, and the financial and managerial skills needed to run a successful small business.

TABLE 3 Origins of some of the world's major food-processing companies


Food company


Bock beer was invented in the German town of Einbeck, and is still manufactured there


Lowenbrau brewery opened in Munich, Bavaria and remains in production there today


French distiller, Jean Martell, began brandy production in Cognac, France


The chocolate company, Rowntree, had its beginnings in a grocery store in York, UK


The first margarine factory was opened by Jan and Anton Jurgens at Oss in Holland


H J Heinz joined his brother and cousin to produce tomato ketchup and pickles


Acream separator was invented by Swedish engineer, Carl Laval, whose company is now Alfa-Laval


Swiss miller, Julius Maggi introduced powdered pea and beet soups, later to become "Maggi" Maggi cubes


Coca-Cola was bottled under contract for the first time by Benjamin Thomas and Joseph Whitehead in Tennessee, USA, instead of syrup being mixed with carbonated water at the point of sale

(Adapted from Trager 1996)

CASE STUDY 1 Confectionery production in Sri Lanka

Mr and Mrs Chandradasa live in rural southern Sri Lanka. After a short training programme in 1994, they started to produce a range of confectionery products in their kitchen using simple domestic equipment. They make approximately 1 800 sweets per week and sell them in local shops. All ingredients and packaging materials are available locally, but they are unhappy with the quality of the labels, and are seeking better ones to improve their marketing. Their main problem is that shopkeepers have the upper hand and will not pay them until the products are sold. Despite these problems, they have increased their turnover to such an extent that Mr Chandradasa has been able to leave his regular job, and they have saved enough money for a purposebuilt building for confectionery production. They have also built a 6-loaf bread oven and are baking two batches of bread per day. They hope to expand this new venture if there is sufficient demand. (Source: Edirisinghe, 1998).

If the level of investment at this scale is too high for individual families, an alternative approach is for a group of people, such as a farmers' group, or a women's group, or a producer co-operative to operate the food processing business together (Case study 2). They invest jointly in the equipment and facilities, and market their products under a single brand name. There are many advantages to this approach including a greater willingness by lenders to make a loan if a group is sharing responsibility for the repayments, new employment opportunities for those without land, discouraging migration to larger towns or cities, and providing greater financial security and an improved standard of living to larger numbers of people.

FIGURE 1 Small-scale processing. (Photo by the author)


CASE STUDY 2 Forest fruit processing

The Kalahan Educational Foundation (KEF) is a people's organization set up by tribal elders, which operates an income-generating project in the Philippine Cordillera Mountains on the island of Luzon. Traditional slash and burn farming practices have been under threat from logging companies for many years, and pressure to maintain income levels has caused many farmers to live and work outside the area. KEF took over the management of 15 000 hectares of forest reserve. They planted fruit trees and employed guards to protect the ancient forest from illegal clearances. They also set up a food processing centre to process forest fruits such as wild guava, wild grape, passion fruit and tamarind into high quality jams, fruit butters and jellies. Over 25 percent of the 540 families living in the reserve area gain significant cash income from bringing forest fruits to the factory. They are processed and packaged into glass jars bought from Manila. Fruit wastes are fed to pigs and their waste is converted to biogas to fuel the factory. The unit produces 40 000 jars of product per year and sells 85 percent of it in Manila through high-class supermarkets. They currently have 2 to 3 percent of the market and aim for 10 to 12 percent. Their customers are typically professional people who appreciate the higher quality compared to competitors' products, and for whom price is not a major issue. They are also exporting their products to Europe via a fair trading organization. (Source: Good 1997).

Many governments promote the development of small-scale food processing enterprises because they:

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