Chapter 1 Basic principles

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1.1 The importance of quality assurance

Small and medium sized food processing businesses all over the world increasingly have to consider the production of good quality products as essential to their survival. Consumers and buyers are becoming more aware of the importance of safe, high quality products. Large companies that can afford advertising space on the radio, television or in the press emphasise the quality of their goods, often in a very subtle way. This quality image is given by stating for example "our foods are made only from high quality ingredients." They also project a quality image through packaging etc. Producers who sell intermediate products, such as dried fruits, to a secondary processor will find that the buyer expects the foods to meet an agreed standard. In the case of exporters, these standards are becoming more and more strict.

In order to improve and control product quality it is essential to fully understand the meaning of the term quality. A common definition is "achieving agreed customer expectations or specifications". In other words, the customer defines the quality criteria needed in a product. To meet this standard the manufacturer puts in a Quality Control System to ensure that the product meets these criteria on a routine basis.


1.1.1. Quality control or quality assurance

The following examples using baked goods illustrate the difference between quality control and quality assurance. A customer may specify that bread should be white, with a good loaf volume and pleasant flavour and taste. The manufacturer then needs to focus on the process to ensure that the raw materials are consistently handled to produce uniform white loaves with the expected volume and taste.

Controlling quality may be achieved by:

However, this Quality Control approach is focused on the process whereas the problems that customers may face can also occur elsewhere in the production and distribution chain. The following examples highlight the shortcomings of a simple quality control approach.
Problem: Many of the loaves are contaminated with pieces of wood.
Reason: The distribution system involves transporting the loaves on wooden trays to retail stores where the loaves are packaged and then sold to customers. The wooden trays are not part of the quality control system because they are used after the product has left the bakery.
Problem: A particular customer has asked for loaves of a different size and colour but these do not arrive as requested.
Reason: The sales staff have no formal procedure for informing the production staff about changes in this customer's specification. The problem has occurred because of missing links in quality management in the bakery.
Problem: Bread has been returned because of a bad flavour and some customers have complained that they have been made ill.
Reason: The flour has been stored next to cleaning chemicals in the dry goods store. One old unlabelled chemical container has been found to have leaked. The company have no documented rules for the storage and handling of chemicals.
The staff who routinely clean the store are not trained and receive lower wages than other members of the production team. The container is old and unlabelled (Fig. 1).

Figure 1: Hazardous storage of chemicals

In order to overcome the types of problems outlined above, a wider approach than quality control is required. This is termed Total Quality Assurance.

Quality Assurance systems take a much wider view of what is involved in satisfying customers' needs. The quality assurance system focuses on the prevention of problems and not simply on their cure. Curing problems is expensive and quality cannot be 'inspected into' a product.

A quality assurance approach therefore, includes the whole production and distribution system, from the suppliers of important raw materials, through the internal business management to the customer. Quality assurance systems should be documented in a simple way to show who has responsibility for doing what and when. The focus of quality assurance is prevention and this should mean that action is taken to meet a specification and prevent failures from occurring a second time. This is done by planning, management action, agreements with key suppliers and other people in the distribution chain.

Quality assurance can only be operated when staff are well trained and motivated. Workers are normally well aware of the causes of most problems and when quality assurance is used properly they can resolve most quality problems within their control. It is the responsibility of business owners to ensure that the quality assurance system, together with any necessary equipment and information, are available to the workers to allow them to exercise this control. The importance of people in quality assurance is represented in Fig. 2.

Figure 2: Good staff are important in quality assurance

It is important to recognise that any system is operated by people. It is people who manufacture a food product and ensure that it has the right quality. People working together ensure that the information, materials and equipment are all correct to allow the production of a product. People also store the product and deliver it on time. All therefore need the necessary training and skills to complete their tasks correctly. They need to know what their own responsibilities are in this quality chain and where they fit into the overall system.

Business owners must not regard communication as a one-way process. The information they send to workers must also be modified by feedback from the staff. Well trained and informed staff are an essential element of the Quality Assurance approach. The other main element of the quality assurance approach which ensures that the system works is to document in a simple way the procedures and responsibilities within a team of workers.

Consider the problems faced by the bakery described previously:

Problem 1 The use of wooden trays

This problem was related to the use of trays by the distributor. Who was responsible for arranging the contract with the distributor and specifying the use of wooden trays?

A quality assurance system ensures that this link in the chain is discussed by the manager and staff and that proper controls and arrangements with the distributor are put into place (for example, plastic sheets on the wooden trays). The producer needs to use the complaint information to modify the process and prevent the complaint occurring again. The types of complaints should be recorded, sources of the problem identified within the factory or supply chain and control measures put into place.

Problem 2 The customer requiring special bread

The internal business communication broke down and important information did not reach the production staff.

A quality assurance system ensures that this communication is constantly operating and being improved. Responsibility and authority are defined and written down.

Problem 3 Tainted bread causing sickness

The management had not identified and controlled the potential hazard that improper handling and storage of chemicals can cause. The effective creation of a quality assurance system should include an assessment and development of methods to control or prevent hazards.


Quality Assurance systems are not mysterious and need not be complex. They simply require the business to agree what are the customers' needs and then ensure that staff have the skills, materials, and information needed to deliver the promises that are made.... every time. A quality assurance system should not be static but it should be continually modified and refined.

This requires an investment in training people to ensure that the quality assurance system controls the essential steps in the whole manufacturing and distribution process to satisfy customer needs.

A range of problem solving techniques can be provided for process workers to use when trouble arises during production. These simple techniques are tried and tested. They involve problem identification, analysis of the cause, suggestions for solutions and implementation and feedback methods. These techniques allow the operators more control over their work and allow problems to be prevented rather than solved. More advanced statistically-based methods can be used for sampling plans and process optimisation but these are beyond the scope of this book.

One of the main building blocks used for developing a quality assurance system is the 'Hazard Analysis Critical Control Point' system which is described in the next section.


1.1.2 Analysing food processes to improve quality using hazard analysis

All food companies, including the smallest manufacturers, have a responsibility to provide consumers with safe, wholesome foods. Safety is not an option but it is an essential part of the planning, preparation and production of foods. Any lack of consideration of safety can result in a serious threat to public health. This is recognised by the law in most countries and serious penalties exist for those who contravene hygiene and food safety legislation. At present in many countries, enforcement staff are not always sufficiently resourced to be fully effective, but this situation is changing as consumers become more concerned about food safety.

An important management method to ensure the safety of foods is the Hazard Analysis Critical Control Point (HACCP) system. This is based on quality control, microbiology and risk management and it has been adopted throughout the world, although some countries have tailored the approach to the needs of their particular food sectors. Many small producers may consider that the development of HACCP systems is not feasible or appropriate to their current needs. However larger manufacturers and producer groups who export to industrialised countries are increasingly finding that HACCP is not a matter of choice but is demanded by the importing company. With time, it is likely that the use of HACCP will be more broadly required by food manufacturers. For this reason a brief description of the application of HACCP is included in this book and examples are given using a number of commodity groups.

This Chapter examines the basic principles and practical methods for implementing the HACCP approach that are adopted to analyse a process and identify where improvements are needed in safety or quality.

An understanding of problems of food safety and quality improvement can start in one of a number of different ways. It can begin for example with an analysis of customer complaints to identify their types and frequency. However, in many developing countries the mechanisms and habit of reporting faults to a producer do not exist and many manufacturers have little knowledge of customers' reactions to their products.

An alternative approach is for the processor to carefully examine every stage in a process to see where and how improvements can be made in the quality and safety of the finished products. The aim of such an exercise is to focus the attention of operators and the manager on the prevention of problems rather than cures, by identifying potential hazards or quality failures and then developing preventative measures for their control.

To implement such an analysis it is necessary to first decide whether the work will focus on improvements to product quality or improvements to the safety of foods. These are obviously connected as food safety is one aspect of quality, but they should be treated as separate exercises.

The level of risks is then assessed and procedures are implemented to monitor and control these risks. If analysis of safety is selected, it is necessary to identify the hazards in a process. This is especially true for high-risk foods (those that can support the growth of food poisoning micro-organisms). If high-risk foods are involved then the severity of the hazard is greater and these food products must be investigated thoroughly as very stringent controls are needed. It is for this reason that inexperienced producers should not be encouraged to make high-risk foods such as canned meats and fish.

If quality improvement is selected, it is necessary to identify where a loss in quality is likely to occur in the raw materials or the process and then find methods to control the procedures that are used in order to improve quality in the finished product.

Most small-scale processors do not have the necessary skills or time to conduct such a study, and it is likely that assistance will be needed from other people who have the necessary experience. Ideally a small team of people should be assembled to effectively analyse the process and then develop and implement the improvements for the selected product. Those selected should have appropriate expertise of the product, the processing operations, microbiology and quality control. Staff from a manufacturer's association, the local Bureau of Standards, Government Regulatory Food Control Office, a University, Trading Standards Department or suppliers may be suitable resource people to assist staff from the food business itself.

For example if the focus of the group is to improve product safety it should conduct its work in the following way:

Gather information

Table 1: Types of contaminant
Hazard Example
Microbiological yeasts, moulds; bacteria, viruses
Biological bone, hair, insects, faeces
Chemical pesticides, toxins, cleaning liquids
Physical wood, string, dirt, etc.

Find solutions

Table 2: Examples of questions used to assess the level of risk in foods

What is the product formulation?

What types of micro-organisms are likely to be present in the raw materials?

What is the pH of the product?

What is the moisture content of the product?

Are preservatives used?

Will any of these factors prevent microbial growth?

What is the intended process?

This should be considered in relation to micro-organisms of concern. Stages in the process that destroy, reduce or allow survival of micro-organisms should be evaluated (including conditions of intended distribution and use, temperatures and times of processing, types of packaging, expected shelf-life, storage and final use).
How will the product be prepared for consumption, is there a risk of mishandling by consumers?

Will the product be consumed by susceptible people (for example children eating weaning foods)?


Monitoring and documentation


When the focus is on quality improvement, a similar sequence of events is used. The quality problems are first identified and possible causes and solutions are discussed. If the problem is associated with poor quality raw materials or ingredients for example, this should be negotiated with suppliers and if needed, quality testing methods can be introduced with agreed tolerance limits. If the problem is associated with the process, for example a critical heating time, then improved process control measures are introduced. In all cases staff must be fully involved and trained so that the improved quality management is sustainable. The effects of any changes should be carefully monitored and recorded.

Such systems need not be complex. Only limited documentation is required and this should assist the small scale processor rather than prevent flexible working. These simple systems are designed to control the key parts of the process and help producers to concentrate valuable manpower where it is most effective. Examples of how this can be done with specific commodities are described in Chapter 2.

1.2 Building design and equipment layout

The type of building in which food products are manufactured and the general level of plant hygiene have a major influence on product quality. In this chapter, basic principles of the correct design of buildings, layout, cleaning of equipment and worker hygiene are described.

Ideally a food manufacturer should have a building constructed specifically for the purpose, but in reality this rarely happens and an existing building has to be modified. If care is taken in the way that the building is adapted, it adds little extra to the total cost but it ensures that the unit is appropriate for food processing.

The Site

The location of the building is very important but is often ignored at the outset. The following examples are points that need consideration and many of relate to quality aspects:

The site should be on cleared ground, away from sources of insects, rodents or smells. It should have a good supply of potable water and if required, electricity. A road access for bringing in raw materials and packaging, and sending out products is usually essential (Figure 4: Selecting the correct site for a food processing building).


The external appearance of the building is a key factor that can influence customers to believe that the company has good management (Figure 5: Examples of a suitable and unsuitable building for processing foods). The points described below can enable quality assurance procedures to be better implemented. Externally and internally the building should be clean and painted, with a professionally made nameplate. Ideally the surrounding area should be planted with grass, as short grass acts as a very efficient trap for airborne dust.

Washing and toilet facilities must be provided, preferably in a separate building. If this is not possible there must be two closed doors between the toilet and the processing area to prevent insects and odours from entering.

All internal walls of the building should be smooth plastered and painted with a water-resistant paint so that they can be washed. Ideally walls should be tiled to about one to one point five metres above ground level. If this is too expensive then tiling should be carried out around sinks and on walls where food may be splashed.

The bottom of the wall, where it meets the floor, is often forgotten. A right angle joint is difficult to clean and can collect dirt. The concrete floor should be curved up to meet the wall (Figure 6: Some desirable features in a food processing building) and so provide a smooth surface that is easily cleaned. Similarly window ledges should slope so that they do not collect dust, dirt or old cloths that may be left there by workers.

Most manufacturers are aware that windows should be fitted with fly-proof mesh, but they often forget other points through which insects, birds and rodents can enter the processing room or store-room. Important areas are gaps where the roof meets the walls and gaps in the roof. Rats are also able to get into buildings along power lines and these should be fitted with metal discs at least twenty five centimetres in diameter.

In tropical climates, a large overhanging roof shades the walls, making working conditions better and providing a useful area for activities such as bottle washing.

Most types of food processing involve the use of large amounts of water, and floors must be designed so that they drain efficiently. The best way to do this is to slope all floors to a central drainage channel (Fig. 6). The drain should be covered with a removable grating to allow cleaning. Drains are a favourite entry point for pests such as rats and cockroaches and the outlets must be fitted with a removable fine mesh.

All electric power points should be fixed at least one to one point five metres high on the walls to keep them dry. Any 3-phase equipment should be installed by a competent electrician. Although they are expensive, waterproof power points are preferred in wet areas. Fluorescent tubes provide good lighting for general work but it must be remembered that normal bulbs should be used near to machines with fast moving parts. This is because fluorescent light can cause a rotating machine to appear stationary at certain speeds; an obvious hazard to workers.

Many food processing operations involve heating, often with the production of steam.

Good ventilation is therefore essential and large mesh covered windows, roof vents and ceiling fans should be used. Extraction fans may be required above boiling pans if the heat cannot be removed from the room by other means.

Water quality is essential to quality assurance and food processing requires a good supply of clean, potable water for cleaning equipment, cooling filled containers and sometimes as a food ingredient. In many parts of the world the main water supply is unreliable and the manufacturer must use other methods to overcome water supply problems.

A simple way to do this is to build a double-chambered high level water tank (Figure 7: Double tank water purification system). This allows cloudy water to settle and be treated with chlorine in one chamber of the tank, while the other chamber is being used. Water treatment is described in more detail in Chapter 1.3.

Equipment and layout

Poor equipment layout can be blamed for many quality problems in food factories. In many small factories workers can be seen almost working against each other, colliding and dropping things. However, good planning and risk assessment can be used to avoid many such errors. The two broad principles to remember are:

1.3 Sanitation and hygiene

Buildings and equipment

The building and equipment must be kept clean at all times as part of a planned quality assurance programme. A thorough clean-down at the end of the day is essential but this alone is not sufficient. Workers must also be trained to keep equipment clean throughout the day and to remove wastes from the building as they accumulate.

The type and frequency of cleaning depends on the food being processed. The most important point is that the manager identifies all areas of potential hazard, then develops a cleaning plan and makes sure all staff are trained and know their particular responsibilities. Most importantly, the manager should allow adequate time for cleaning down. Too often the final clean-down is carried out in a rush during the last few minutes of the day.

In dry processing, or in processes that use dry powders such as flour, it is essential that all dust is cleaned from the building, not forgetting high window ledges, old sacks etc. The objective is to prevent any areas collecting dust where insects can breed.

For wet processes, cleaning involves the use of both detergents and sterilants. Detergents remove food residues but do not kill micro-organisms. Sterilants (mainly chlorine) kill microorganisms but do not remove residues. Therefore for good cleaning the residues are first removed with a detergent and the equipment is then treated with a sterilant. A large range of detergents is available for different uses (for example to remove scale or fat). Manufacturers should investigate which types are available locally and consult suppliers to find the best type for their process.


Chlorinated water is needed for cleaning, washing raw materials and as an ingredient in some products. The required level of chlorine depends on the use of the water. Water for cleaning requires a high level of chlorine; up to 200 ppm (parts per million, the normal method of expressing chlorine levels). Water used in a product should contain about 0.5 ppm to avoid giving a chlorine flavour to the product.

There are a number of ways of preparing chlorinated water for use in the processing plant. The simplest way is to use household bleach, which is readily available in most countries. Table 3 shows the dilutions needed to give different chlorine concentrations.

Table 3: Dilution of bleach
Amount of bleach (ml) Amount of water (litres) Chlorine concentration (ppm)
1000 250 200
500 250 100
25 250 5
2.5 250 0.5

Alternatively bleaching powder can be used. This is cheap and when fresh, contains 33 % chlorine. The powder does however weaken with time and tins should always be kept sealed when not in use. Bleaching powder is used by making up a 1% chlorine solution (30-40g per litre). This is then diluted for use: for example 6mls in 45 litres of water gives a 1ppm solution.

In cases where a pumped water supply from a well is being used it is common practice to use the action of the pump to automatically dose the water supply with a strong chlorine solution. A typical chlorine dosing installation is shown in Fig. 9 (see Figure 9: A typical chlorine dosing installation), and methods for measuring chlorine levels are described in Chapter 3 (chlorine measurement).

A full discussion of methods of water treatment and chlorination are beyond the scope of this book and further reading is given in Appendix 1.

Although chlorine has the great advantage of killing a wide variety of micro-organisms, it also has several disadvantages: it may corrode equipment, particularly aluminium; it can leave flavour taints if it is not rinsed well with potable water; pure bleach MUST BE HANDLED WITH CARE as it can damage the skin and particularly the eyes, as well as cause breathing difficulties.

In addition water in many rural areas of developing countries may be slightly cloudy. This suspended material can be cleared by allowing the water to stand for a few hours before use. A double chambered tank combining settling and chlorination can be fitted onto the roof of a building (Fig. 7). The tank should have a sloping bottom and be fitted with drain valves at each end. Both tanks are filled at the end of the day and chlorine solution is added at the required level. By the morning the suspended solids will have settled. In use, water is drawn off from the high level valve and when the tank is almost empty the low level valve is opened to flush out any settled material. The tank is then refilled and the water allowed to settle while the second chamber is used.

Operator hygiene

Operators are a potential source of contamination of foods but to a considerable extent the risk depends on the type of food products. For example, a food that is hot-filled into a bottle, sealed and then heat-treated carries a far smaller risk than a baked meat pie which is handled after it has been cooked. The manager should evaluate the risk and ensure that hygiene procedures are established in the factory and that they are appropriate to the types of products being made. Such measures include the following:

It is very important that workers do not get penalised for having an infection, otherwise they will tend to hide their problem. They should be found other duties; for example, there is always a backlog of cleaning, painting and repairs to be carried out in a production unit. The task of a good manager is to ensure that staff are aware of the risks associated with infections and in this connection wall posters of good and bad practices are very useful. Some of these are available in blank form so that a message can be written in any local language (Appendix 1). A example of a poster is shown in Fig. 10 (see Figure 10: Examples of food hygiene posters).

Cleaning schedules

The overall cleanliness of a food processing unit, however small, can have a major impact on the quality of finished products. For example, particles of food that are trapped in the corner of a tank or in a pipe, can allow the growth of micro-organisms and this can cause massive contamination of products the following day.

Cleaning schedules should be seen as an integral part of an overall quality assurance system and a responsible producer carries out a HACCP analysis of cleaning. Areas of hazard need to be identified, the severity of risk evaluated and cleaning procedures put into place. All areas need attention but some carry a greater risk than others. For example in a small bakery producing meat pies, all surfaces that contact raw meat should be seen as having the highest risk and they should receive the most stringent attention. Each worker should know their cleaning responsibilities within the overall schedule, The owner must take overall responsibility to ensure that cleaning takes place to the correct standard. It is useful to use cleaning cloths and brushes made of brightly coloured materials as these show up easily if they contaminate foods. It is recommended that a cleaning schedule book is maintained which details the area or item to be cleaned, how, when and who is responsible.

1.4 Regulatory quality control

Almost all countries in the world now have laws governing the production, composition, labelling and safety of processed food and an Agency that is responible for their implementation. In some countries this agency is the Bureau of Standards in others it may be a division of a Ministry such as Agriculture, Health or Trade and Industry. Although the degree to which national food legislation is currently applied varies greatly from country to country, food manufacturers should be aware that the overall trend is to more stringent application, inspection and control by the responsible authority. National food legislation varies considerably in detail from country to country but applies to three broad areas:

A food manufacturer contravening national food legislation is subject to penalties which can, in extreme cases, be very severe and involve forced closure of the plant and heavy fines. Manufacturers should be aware that consumers are becoming increasing concerned about food safety and quality issues and are thus more likely to take complaints to the local food control authority. This greatly increases the likelihood of inspection of the premises and products with the resulting risk of penalties.

Food processors should therefore ensure that they know how local legislation applies to their production unit and products. Copies of relevent laws should be obtained and the entire production system should be monitored to ensure that it meets the requirements. Producers that export foods face an even more difficult situation and need obtain copies of relevent food legislation of the importing country as this may vary from their own. In some cases for example, it may be found that a product will need to be reformulated or specially labelled to meet the laws of the importing country.

Unfortunately the authorities charged with the application of food laws are often seen by manufacturers as being threatening and simply "policing" production activities. Ideally food producers should try to use these authorities as advisers. In many cases they will be able to provide useful guidance to avoid a problem developing (for example checking that a new label design meets local requirements prior to spending money on printing).

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