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3.1 Traditional quality control (Hans Henrik Huss/John Ryder)

The traditional quality control program was based on establishing effective hygiene control. Confirmation of safety and identification of potential problems was obtained by end-product testing. Control of hygiene was ensured by inspection of facilities to ensure adherence to established and generally accepted Codes of Good Hygiene Practices (GHP) and of Good Manufacturing Practices (GMP).

Traditional Quality Control

Codes of GHP/GMP
Inspection of facilities and operations
End-product testing

Codes of GHP/GMP are still the basis of food hygiene as outlined in Chapter 7. However, codes - although being essential - only provide for the general requirements without considering the specific requirements of the food and the processing of specific foods. Also the requirements are often stated in very imprecise terms such as "satisfactory", "adequate", "acceptable", "suitable", "if necessary", "as soon as possible" etc. This lack of specifics leaves the interpretation to the inspector, who may place too much emphasis on relatively unimportant matters. He may fail in distinguishing between "what is nice and what is necessary" and consequently increase the cost of the programme without reducing the hazards.

Perhaps one of the most common mistakes that many inspection services and some food companies make is to rely on end-product testing. Very often this has been the only quality and safety assurance system applied. Samples have been taken randomly from the day's production, and examined in detail in the laboratory. There are several problems related to this procedure:

It is important to understand the ineffectiveness and limitations in using end-product sampling and testing to ensure product safety. In most cases there is no test that give an absolutely accurate result with no false positives and no false negatives. This is certainly the case for all microbiological testing. Furthermore, there are the principles of sampling and the concept of probability to consider.

3.1.1 Principles of sampling

The number, size and nature of the samples taken for analysis greatly influence the results. In some instances it is possible for the analytical sample to be truly representative of the "lot" sampled. This applies to liquids such as milk and water. However, in cases of lots or batches of food this is not the case, and a food lot may easily consist of units with wide differences in (microbiological) quality. Even within the individual unit (i.e. a retail pack) the hazard (i.e. the presence of pathogens) can be very unevenly distributed, and the probability of detecting may be very low (Table 3.1).

Table 3.1 Detection probabilities - end-product testing of milk powder contaminated with Salmonella (Mortimore and Wallace, 1998).

Contamination rate

Number of random samples

Probability of detection1

Homogenously contaminated

5 cells/kg



1 cell/kg



Heterogeneously contaminated

5 cells/kg in 1% of batch



104 cells/kg in 1% of batch



1. Assuming detection test is 100% effective (most are <90%)

In this example, a contamination rate of Salmonella at 5 cells/kg and assuming the contamination is restricted to 1% of the batch, the probability of detecting the hazard by taking 10 samples of 25 g would be lower than 2%. If the contamination with Salmonella is homogeneously distributed at the same rate, probability of detection would increase to 71%.

A sampling plan (Attributes plan) can be based on positive or negative indications of a micro organism. Such a plan is described by the two figures "n" (number of sample units drawn) and "c" (maximum allowable number of positive results). In a 2-class attributes sampling plan, each sample unit is then classified into acceptable or non-acceptable. In some cases the presence of an organism (i.e. Salmonella) would be unacceptable. In other cases, a boundary is chosen, denoted by "m", which divides an acceptable count from an unacceptable. The 2-class sampling plan will reject a "lot" if more than "c" out of "n" samples tested are unacceptable.

In a 3-class sampling plan "m" separates acceptable counts from marginally acceptable counts and another figure "M" is indicating the boundary between marginally acceptable counts and unacceptable counts as shown in Figure 3.1.

Figure 3.1 Two- and three-class attributes plans (based on ICMSF, 2002).

3.1.2 The concept of probability

The safety which can be obtained with such sampling plans depends on the figures chosen for "c" and "n". This can be illustrated with the so-called operating characteristic curves which are demonstrating the statistical properties of such plans (Figure 3.2).

Figure 3.2
Operating characteristic curves for different sample sizes (n) and different criteria of acceptance © for 2-class attributes plan (ICMSF, 1986).

The figures show that the greater the number of defective units (Pd), the lower is the probability of acceptance (Pa) of the lot. It is further demonstrated, that high value of "n" and low value of "c" reduces the risk of accepting lots with same number of defective units. It can be seen that testing of foods for the presence of contaminants offers very little protection even when large numbers of samples are examined as also shown in Table 3.2.

Table 3.2 Effect of lot quality (% defective in a lot) on the probability of acceptance (%) for different 2-class sampling plans (based on EC, 1998).

% defective samples in lot

probability of acceptance (%) given sampling plans with a total of "n" samples and allowance of "c" defect samples

n=1, c=0

n=5, c=0

n=10, c=0

n=60, c=0


























Table 3.2 clearly shows, that lot testing is not effective when defect rates are low. A product safety defect rate of 1% is absolutely intolerable in many food operations. Potentially, it represents 10 000 unsafe units per one million units manufactured. More than 3 000-5 000 units would need to be sampled and tested in order to detect a 1% defect rate with 95% or 99% probability (Corlett, 1998).

It is evident, that even the most elaborate sampling and testing of end-product cannot guarantee safety of the product. There is no way to avoid some degree of risk and error in each acceptance and each rejection of lots unless the entire lot is tested, in which case no edible food will be left.

3.2 Modern safety and quality assurance methods and systems (Hans Henrik Huss/John Ryder)

To the uninitiated, and also the initiated, there may seem to be a whole host of different options or methods for ensuring the safety and quality of food products. The situation is not helped by the acronyms arising from these methods i.e. ISO, GMP, GHP, HACCP, TQM, etc. seeming to have a life of their own and coming into modern usage as words in themselves, and sometimes used without an understanding of what they mean.

This brief section tries to succinctly define what each of these methods are and what they were designed to achieve.

While this book focuses on the technical aspects of managing quality including safety, it is important to note that companies are also managing other aspects of quality in their companies, which, for instance, could be categorized under managerial and environmental concerns. These are expanded upon in the table below (Table 3.3). The table is more indicative than exhaustive and merely serves to highlight the main items that need to be considered in managing quality in a company. It is maybe obvious to state that it is vital to ensure that all these factors are managed effectively and efficiently in order for companies to survive in today's competitive environments. Unfortunately, it is not uncommon to find companies ignoring these principles.

Table 3.3 Categorization of items to be managed in a company.

Management concern

Items to be managed


Intrinsic quality of fish (taste, smell and texture); safety; spoilage/ freshness; grading; packaging; nutritional; authenticity; shelf life, etc.


Administrative systems; customer relations; promotion; delivery commitments; invoicing and payment, etc.


Waste and water management; noise pollution; odeurs; pollutants, etc.

3.2.1 Methods to manage quality and safety

So, what is there in existence to manage quality and safety, and how do they relate to each other?

Below are listed the most well known methods to manage quality and/or safety, and these will be briefly discussed individually and then how they integrate with each other.

The food safety tools and their relationship is shown in Figure 3.3.

Good Hygienic Practices / Good Manufacturing Practices

The terms GHP and GMP basically covers the same ground as discussed in Chapter 7. They refer to measures and requirements which any establishment should meet to produce safe food. These requirements are prerequisites to other and more specific approaches such as HACCP, and are often now called prerequisite programmes. In recent years the term Standard Sanitary Operating Procedures (SSOP) has also been used in the US to encompass basically the same issues, i.e. best practices.

Hazard Analysis Critical Control Point

Hazard Analysis Critical Control Point (HACCP) is a systematic approach which identifies, evaluates, and controls hazards which are significant for food safety (CAC, 1997). HACCP is discussed in great detail throughout this book. In the context of this section, HACCP ensures food safety through an approach that builds upon foundations provided by good manufacturing practice. It identifies the points in the food production process that require constant control and monitoring to make sure the process stays within identified limits. Statistical Process Control systems are relevant to this operation.

Figure 3.3 Food safety tools: an integrated approach (modified from Jouve et al., 1998).

HACCP is legislated in many countries, including the USA and the European Union. The combination of GHP/GMP and HACCP is particularly beneficial in that the efficient application of GHP/GMP allows HACCP to focus on the true critical determinants of safety.

Quality Control

Quality control (QC)

Can be defined as the operational techniques and activities that are used to fulfil quality requirements (Jouve et al., 1998)

It is an important subset of any quality assurance system and is an active process that monitors and, if necessary, modifies the production system so as to consistently achieve the required quality.

It can be argued that QC is used as part of the HACCP system, in terms of monitoring the critical control points in the HACCP plan. However, traditional QC is much broader than purely this focus on critical control points for safety systems. The pitfalls of relying on QC procedures, more importantly as end product testing, have been detailed in section 3.1 and will not be expanded upon here.

Quality Assurance / Quality Management

This can be defined as all the activities and functions concerned with the attainment of quality in a company. In a total system, this would include the technical, managerial and environmental aspects as alluded to above. The best known of the quality assurance standards is ISO 9000 and for environmental management, ISO 14000.

The term quality management is often used interchangeably with quality assurance. In the seafood industry, the term quality management has been used to focus mostly on the management of the technical aspects of quality in a company, for instance, the Canadian Quality Management Programme which is based on HACCP but covers other technical issues such as labelling.

ISO Standards

The International Organization for Standardization (ISO) in Geneva is a worldwide federation of national standards bodies from more than 140 countries.

The mission of ISO is

to promote the development of standardization and related activities in the world with a view to facilitating the international exchange of goods and services, and to developing cooperation in the spheres of intellectual, scientific, technological and economic activity (

ISO's work results in international agreements which are published as International Standards. The vast majority of ISO standards are highly specific to a particular product, material, or process. However, two standards, ISO 9000 and ISO 14000, mentioned above, are known as generic management system standards.

Over half a million ISO 9000 certificates have been awarded in 161 countries and economies around the world and in 2001 alone over 100 000 certificates were awarded, 43% of which were the new ISO 9001:2000 certificate.

Historically, the ISO 9000 series of standards of relevance to the seafood industry included:

More recently, the new ISO 9001:2000 certificate is the only ISO 9000 standard against whose requirements a quality system can be certified by an external agency and replaces the old ISO 9001, 9002 and 9003 with one standard.

It is important to note that the ISO 9000 standards relate to quality management with customer satisfaction as the end point, and that they do not specifically refer to technical processes only. ISO 9000 gives an assurance to a customer that the company has developed procedures (and adheres to them) for all aspects of the company's business.

ISO 14000 is primarily concerned with environmental management. Introduced much later than the ISO 9000 series, there are now over 35 000 ISO 14000 certificates awarded in 112 countries or economies of the world. During 2001, nearly 14 000 certificates were awarded, around 40% of the total awarded since the introduction of the standard.

In most countries, implementation of ISO 9000 quality management systems or ISO 14000 environmental systems are voluntary.

Quality Systems

This term covers organizational structure, responsibilities, procedures, processes and the resources needed to implement comprehensive quality management (Jouve et al. 1998). They are intended to cover all quality elements. Within the framework of a quality system, the prerequisite programme and HACCP provides the approach to food safety.

Total Quality Management (TQM)

TQM is an organization's management approach, centred on quality and based on the participation of all its members and aimed at long-term success through customer satisfaction and benefits to the members of the organization and to society (Jouve et al. 1998). Thus TQM represents the organizations' "cultural" approach and together with the quality systems provides the philosophy, culture and discipline necessary to commit everybody in the organization to achieve all the managerial objectives related to quality.

3.3 Risk analysis, food safety objectives (Lone Gram)

The management and control of (sea)food borne diseases is carried out by several groups of people. It involves experts assessing the risk, i.e. providing the epidemiological, microbiological and technological data about the pathogenic agent, the food, the host etc. It involves risk managers who at government level have to decide what level of risk society will tolerate and risk managers in both industry and government that have to implement procedures to control the risk. At industry level this is done using GHP and HACCP procedures as described below.

The term "risk analysis" it the process underlying development of food safety standards (FAO/WHO, 1997). It consists of three separate but integrated parts, namely risk assessment, risk management and risk communication. The risk analysis process must be open and at every step all stakeholders should be allowed to participate and comment. It has been seen as important that there is a separation between the risk management and the risk assessment (FAO/WHO, 1995). The risk assessment is a science based evaluation whereas risk management (at government level) also involves a range of societal issues.

The objective of the rules that govern international trade with food, the WTO/SPS[7] agreement, is to permit countries to set certain safety measures for their population and ask that imported foods allow the same level of public health protection. To justify and compare the levels of public health protection and food safety measures, risks must be analysed using the risk assessment techniques described by Codex (CAC, 1999).

Analysis of risk includes the following steps:

Identification of a food safety problem

A food safety problem may be identified either through a sudden change in disease frequency, i.e. epidemiological data indicate a sudden rise in a particular disease, or the hazard analysis carried out as part of the HACCP system may indicate reason for concern. This could be caused by implementation of new processing technologies, or by changes occurring in population composition.

Assessment of the risk

Evaluating the risk associated with the problem involves estimating the severity of the disease and the likelihood of occurrence. Basically, the magnitude of the problem to public health is being determined. This evaluation of risk can be done by just one or two experts, by an expert panel or a so-called quantitative risk assessment may be conducted. Whether one or the other is chosen depends on the urgency of the matter - sometimes a risk management decision has to be made immediately - and of the complexity and its implications for international trade.

The term "quantitative risk assessment" can be a bit misleading, since any evaluation of risk requires considerations of quantitative aspects. However, it has recently been used to describe a lengthier and structured process in which the impact of different factors from farm to fork that contribute to risk are quantified. Typically this process involves the use of mathematical modelling at several steps using Monte Carlo simulations. An example of a quantitative risk assessment is the FAO/WHO work on Listeria monocytogenes in ready to eat foods (FAO/WHO, 2001). One result of the risk assessment is the graphical representation of dose-response curve in which the likelihood of disease is presented as a function of levels of L. monocytogenes consumed (Figure 3.4).

Figure 3.4
Simulated dose-response function for Listeria monocytogenes in ready to eat foods for consumers in the high risk group. Based on FAO/WHO (2001).

The graph clearly demonstrates that the risk of disease is related to consumption of high numbers of the organism. However, if the risk is expressed as the log value it becomes evident that there is no threshold value below which the risk disappears but even a few cells do carry some, albeit very low, level of risk (Table 3.4). This curve can be used to determine how many cases a particular level of consumption of a pathogen leads to. Based on the consumption pattern and data from the FDA/FSIS risk assessment as well as the risk characterization curve from the same study (FDA/FSIS, 2001), one can predict how many cases are the result of different levels at point of consumption (FAO/WHO, 2001).

The data in Table 3.4 are based on the US situation. The numbers add up to approximately 2 100 comparable to the reported number of cases of approximately 2 500 per year (in a population of a total of 280 million people). Two things are apparent: i) that it is especially the high doses that cause the problem and ii) that even the lowest number of cells carry a low risk of disease.

Establish a public health goal

When determining a public health goal, risk is most often expressed as a number of cases of illness per capita per year. For instance, the level of listeriosis cases in the US is 0.5 per 100 000 of the population per year and recently, the White House announced that this had to be reduced to 0.25 cases per 100 000 of the population per year.

Several terms exist for such public health goals. Ideally, the goal would be to reduce all (sea)food borne diseases to "zero risk", however, this is technically and financially not possible. It is important to understand that there is no such thing as "absence of risk". Therefore, the public health goal is expressed using different terms such as "appropriate level of protection" (ALOP). Realising that no risk is really ever appropriate, the ICMSF (2002) has suggested to use the term "tolerable level of risk" (TLR).

Table 3.4 Baseline number of cases of listeriosis from ready-to-eat foods as predicted by the FDA/FSIS dose-response model (after FAO/WHO 2001).

Maximum log dose at consumption (log CFU/serving)

Number of servings at the specified dose

Number of cases1 per year attributed to a specified dose level



5.93 x 1010


1 case per 100 years


2.50 x 109


1 case per 200 years


1.22 x 109


1 case per 50 years


5.84 x108


1 case per 10 years


2.78 x 108


1 case per 2 years


1.32 x 108


2.4 cases per year


6.23 x 107




2.94 x 107



1.39 x 107



3.88 x 106



2.67 x 106

1 580

8.0 and above

very few


6.41 x 1010

2 130


1. The number of cases is predicted based on the dose and the number of servings containing that dose.

Food Safety Objective

Levels of disease attack rate are difficult to measure and target by food managers in government and industry and therefore the term Food Safety Objective (FSO) has been introduced. The FSO translates risk into a measurable goal and is expressed as the concentration or frequency of a hazard in a food [at point of consumption] that is considered "safe" or meeting the level of protection/risk set by society. The FSO has been used in broad terms by several (Jouve, 1996; Hathaway, 1997) but was explicitly defined by the ICMSF (van Schothorst, 1998).

Food Safety Objective

Concentration or frequency of a hazard in a food [at point of consumption] that is considered safe or meeting the level of protection set by society

If a quantitative risk assessment has been conducted, the FSO is simply the translation for the Y-axis (with disease risk or cases) to the X-axis (with the number or frequency of the pathogen).

FSOs can - and are often - set even when quantitative risk assessments and the risk characterization curve are not available. Investigations of food borne diseases, epidemiological surveillance programmes, industry records and knowledge of the influence of food processing parameters can (and has for decades) provided information about which foods cause adverse health effects, which pathogens are implicated, and, to some extent, which levels of pathogens are involved. In effect, the setting of microbiological criteria for foods has been and is an indirect way of setting an FSO - and thus implies a desired public health goal. Many examples of this are present. One is the standard for Staphylococcus aureus in cooked crustaceans (n=5, c=2, m=100/g and M=1000/g). This criteria contains an evaluation of the risk related to the concentration of the hazard (growth and high concentrations are required to produce the amount of enterotoxin causing disease) (FAO/WHO, 2002).

It is important to realise that FSOs are not equivalent to microbiological criteria but that, if appropriate, criteria can be derived from FSOs. An FSO is a public health goal whereas a microbiological criteria defines acceptability of a food product or a lot of foods and should indicate sampling plan, method, number of units that must conform etc. (see Chapter 13). An example of an FSO is a concentration of 100 L. monocytogenes per gram at point of consumption for ready-to-eat-foods (van Schothorst, 1998; ICMSF, 1994). Criteria for L. monocytogenes at earlier points in the chain will typically be lower than the 100 cfu/gram.

It must be evaluated if the FSO as expressed by risk managers is achievable. If not, it must be decided (i) if changes in the industry has to be enforced, (ii) if the product should be taken off the market or (iii) if the product should be labelled as carrying a risk. Examples of such procedures are (i) the mandatory pasteurisation of milk, (ii) the ban of tetrodotoxin containing fish species for the EU market and (iii) the notice by restaurants in several US states that eating raw oysters may be detrimental to health. Examples of FSOs are shown in Chapter 12.

Implement risk management decisions

When a public health goal has been set, it is the responsibility of risk managers in industry (and government) that measures are taken to control the risk. With respect to food-borne pathogens, the risk can in principle be controlled at three levels:

The primary tools available to the food industry to control safety risks are GHP and HACCP programmes. Incorporated into these programmes may be various processes and criteria that ensure that the FSO (ultimately) is met.

A performance criteria describes the outcome of a process or step. This can for instance be that a canning procedure should ensure a 12D kill of C. botulinum spores or that only 3% of freshly produced cold-smoked salmon must contain L. monocytogenes.

Process and product criteria are statements of values for specific processes, such as time x temperature combinations during hot-smoking, or values such as NaCl-% and pH in the product. For instance, the control of C. botulinum in lightly preserved fish is not carried out by sampling and testing for C. botulinum but by ensuring that the combination of salt and temperature is sufficient to prevent growth.

Acceptance criteria are measurements or statements of conditions that distinguish acceptable from non-acceptable products. These may be based on sensory evaluations, on chemical measurements and may in some cases be microbiological criteria. These should specify the agent to be measured, the number of samples and the method used. As described later (Chapter 13), sampling and microbiological testing is best used for detection of high concentrations or frequencies of microorganisms.

Overall the interaction between government's and industry's roles in food safety activities can be described as below (Figure 3.5).

Risk communication

An integral, and very important step, in all stages of a risk analysis is the communication of risk to stakeholders, including industry and consumers. An important part of the risk communication is using the findings of the risk assessment for training purposes and in the process of setting specifications.

Figure 3.5 Interaction between the government's and industry's food safety activities (modified from Jouve 2000, Jouve et al., 1998).


CAC (Codex Alimentarius Commission) 1999. Principles and Guidelines for the Conduct of Microbiological Risk Assessment. CAC/GL-30. Food and Agriculture Organization / World Health Organization, Rome, Italy.

CAC (Codex Alimentarius Commission) 2001. Food Hygiene. Basic Texts. 2nd ed. Food and Agriculture Organization / World Health Organization, Rome, Italy.

Corlett, Jr. D.A. 1998. HACCP Users Manual. An Aspen Publication, Gaithersberg, Maryland, USA.

EC (European Commission) 1998. Food - Science and Techniques. Reports on tasks for scientific cooperation. Microbiological criteria. Collation of scientific and methodological information with a view to the assessment of microbiological risk for certain foodstuffs. EUR 17638.

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FAO/WHO (Food and Agriculture Organization/World Health Organization) 1997 Joint FAO/WHO Expert Consultation on risk management and food safety. 27-31 January, Rome, Italy.

FAO/WHO (Food and Agriculture Organization/World Health Organization) 2001. Risk Assessment of Listeria monocytogenes in ready-to-eat foods. Preliminary report. Authors Buchanan, R., R. Lindqvist, T. Ross, E. Todd, M. Smith and R.C. Whiting. FAO/WHO, Rome, Italy.

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Hathaway, S.C. 1997. Development of risk assessment guidelines for foods of animal origin in international trade. Journal of Food Protection 60, 1432-1438.

ICMSF (International Commission on Microbiological Specification for Foods) 1986. Microorganisms in Foods 2. Sampling for Microbiological Analysis: Principles and Specific Applications. University of Toronto Press, Toronto, Canada.

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Jouve, J.L. 2000. Good manufacturing practices, HACCP and quality systems. In: Lund, B.M., T.C. Baird Parker and G.W. Gould (eds) The Microbiological Safety and Quality of Foods. Aspen Publishers. Gaithersberg, Maryland, USA. pp.1627-1655.

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[7] The rules were agreed during the Uruguay Round of Trade Negotiations and apply to members of the World Trade Organization (WTO). Food safety matters are ruled by the Agreement on the Application of Sanitary and Phytosanitary Measures (the SPS agreement).

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