Basic facts about food preparation and processing

Introduction

 

Food has been processed since communities first came together thousands of years ago. Most foods need some form of preparation and processing to make them more attractive to eat. Grains, vegetables, meats and fish are each unpalatable in their raw state, and some foods, such as cassava, are dangerous if eaten without processing. Even nuts, milk and fruits that are eaten raw can benefit from processing into a wide variety of other products.

Different types of processing have been developed over generations into the range of methods that we have today. In every region, country and even in individual villages, there are distinctive traditional processed foods that are well suited to the local climatic and socio-economic conditions (for example, the 2 000 different cheeses throughout the world, each with its own distinctive flavour and texture). In villages throughout the world, families inherit or develop specialist skills and become for example the village baker, brewer or fish smoker. Traditional products have a high local demand and are often sought by people in other areas, so establishing trade and the development of local food businesses. In Sri Lanka, for example, some communities are known throughout the island for the quality of their buffalo curd (yoghurt), which is bought by traders and distributed over wide areas. Food preparation and processing therefore benefit communities by:

• increasing the variety of foods in the diet;
• creating special foods for cultural or religious occasions, thus reinforcing cultural identities;
• creating opportunities for sales and income generation.

However, processing does more than change the eating quality of raw foods. All foods are biological materials that begin to decay as soon as they are harvested or slaughtered. Processing slows down or stops this deterioration and thus allows foods to be preserved for extended periods. This benefits village communities in a number of ways.

• It enables food to be stored as a reserve against times of shortage to increase food security (to ensure that sufficient food is available and that essential nutrients are eaten throughout the year).
• It enables crops to be sold out of season when prices are higher.

Processing offers opportunities for villagers to diversify their sources of income. When farmers in an area grow similar crops, processing helps to avoid the effects of lowered prices and incomes when seasonal gluts occur at harvest time. Processing also enables farmers who grow low-value staple crops to add value and increase household incomes. For example, in many African countries processing sorghum into beer or processing cassava into gari or snack foods can form very successful small-scale businesses. In many Asian countries, value is similarly added to fruits and vegetables by processing them into a wide range of pickles, chutneys and other relishes. These small-scale operations are a major source of employment in rural villages, estimated at up to 60 percent of employment in some countries.
Many governments and international development agencies promote food processing as a means of alleviating poverty in rural areas. There are many advantages in choosing food processing over other income-generating activities.

• Food processing is accessible - everyone is familiar with the food that they grow and eat and, compared with some other types of business, there are fewer aspects to learn when getting started. Small-scale food processing is also particularly suitable for women, who may be the specific intended beneficiaries of development programmes.
• If chosen correctly, processed foods can have a good demand and offer the opportunity to generate good profits by adding value to raw materials.
• Crops or animals that are the raw materials for processing are usually readily available (and sometimes in surplus).
• Of the many different types of processing technologies, most are suitable for small-scale operation with an affordable level of investment by rural people.
• Domestic utensils can be used in many processes when starting up.

When production expands, many types of processing equipment can be manufactured locally by metal workshops or carpenters, thus creating further employment.

• Most types of processing have few negative environmental effects.

There are two broad categories of food preparation and processing:

1. Primary processing, in which foods are stabilized after harvest and sometimes converted into a more convenient form for storage. Examples include drying crops, milling cereals and extracting cooking oils from oilseeds or nuts. These types of processing are described in more detail in the accompanying booklet in this series High hopes for post-harvest.

2. Secondary processing, in which fresh foods or the products of primary processing are made into a wide range of processed foods. These are the subject of this booklet.

In the following sections, the booklet describes some of the opportunities and constraints that face communities in developing countries who wish to introduce or improve food processing. It is intended to assist:

• advisers, government officials or development agency staff who wish to promote food processing;
• development workers who wish to set up or improve a food processing unit;
• community leaders and entrepreneurs who are involved in food processing.

Food preparation and processing are important to rural communities to ensure their food security, to increase variety in people's diets, and as a means of generating diversified income and employment. When successful, processing at village level can create an enhanced quality of life for villagers because of greater prosperity and improved health and nutrition.

 

 

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.