The food processing/manufacturing industry is also involved in high-volume ... The control of package weight and quantity, which is regulated under ..... Notes. 1. Escherichia coli. 2. In England and Wales, some aspects of food safety ...
Statistical process control in UK food production: an overview Nigel P. Grigg Glasgow Caledonian University, Glasgow, UK
Statistical process control in UK food production 223 Received July 1996 Revised July 1997
Introduction The benefits which statistical process control (SPC) can accrue to manufacturing processes have long been recognised in the engineering-related industries, particularly in high-volume manufacturing situations, and in those where product quality is synonymous with safety or reliability. Such benefits include accurate assessment of process capability, predictable levels of process control, timely detection of process drift or “special causes” of variation, quantifiable customer quality assurance and effective recording of qualityrelated data (e.g. Cheng, 1994; Chiu and Huang, 1996; Gaafar and Keats, 1992; Gelinas, 1994; Sulek et al., 1995; Wu, 1994; Xie and Goh, 1993;). The food processing/manufacturing industry is also involved in high-volume production, and is one in which product quality control is paramount, owing to the delicate and perishable nature of the product and the potentially severe consequences of a lapse in process control (such as were demonstrated in 1996 when contamination of some meat products in Scotland with the E. coli[1] pathogen had severe and widely reported consequences for the supplier). It might reasonably be expected that SPC is equally widely used in this industry, if not more so. However, while many food companies do make use of SPC, and indeed report benefits from so doing (as reported in this article), others either consider it unnecessary, or else (more importantly) find it so difficult to understand and implement that they are unable to do so effectively, if at all. This paper examines where and how SPC can be of benefit to food producers within the operational frameworks of the relevant consumer protection legislation. Through a survey supported by short case studies, the paper then looks at the nature and extent of current usage of SPC in the industry, in order to ascertain whether more can or indeed should be done to promote or encourage its use within the sector. Food industry legislation and enforcement The main legislatory requirements governing food manufacturing and processing relate to the following two principal areas: •
The safety of food products, which is regulated under The Food Safety Act 1990, and enforced by Environmental Health Officers[2]; and
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•
The control of package weight and quantity, which is regulated under the Weights and Measures Act 1979, and enforced by trading standards officers.
Although these two areas of legislation are mutually exclusive, wherever either Act is of relevance to a food producer, the producer is then obliged to take due cognisance of that legislation in their quality system. The reason is that in the event of an offence under either Act being detected, the producer’s only recourse to avoid prosecution is through claiming the statutory defence that they took “all reasonable precautions”, and exercised “all due diligence”, to avoid the offence (Department of Health, 1995; Fowler, 1994; Schothorst and Jongeneel, 1992). The possession of a documented quality system is, in most cases, sufficient to demonstrate “reasonable precaution”, and evidence of its effective routine operation (i.e. records) sufficient to demonstrate “due diligence”. It is, of course, axiomatic that the routine use of an effective quality system should prevent the occurrence of such offences in the first place, and hence negate the need for such a defence. Food industry guidance literature To assist the food producer in establishing effective quality assurance (QA) systems, based on good manufacturing practice and capable of routinely complying with the legislation, there is a wealth of advisory documentation available from government and industry bodies at European and UK level (e.g. Codex, 1993a, 1993b; DTI, 1979a; ICMSF, 1988; IFST, 1991). The food sector is, however, an extremely diverse one, comprising organisations ranging from small, labour-intensive, family-sized businesses to multi-site, capital-intensive operations employing several thousand people. No less diverse is the range of products, raw materials, production methods and even food safety assurance criteria[3] (Miyagishima et al., 1995). For this reason, specific codes of practice exist, produced by various sources such as CAC, CFDRA[4], BMMA[5] and many others, covering all types of food product and methods of preparation. While these provide detailed recommendations on QA aspects such as hygiene, handling and prescribed limits for process parameters such as in-process temperatures and pH levels, it is not generally the case that they provide any specific information on SPC tools and methods, or indeed recommend use of these. The following sections explore in greater detail the above aspects of food legislation, the main associated publications, and the applicability of SPC within these recommended frameworks. European food safety legislation Regulations under this legislation require food businesses to assess and control potential food hazards. It is recommended that this be carried out “on the basis of the principles used to develop the hazard analysis critical control points
(HACCP) system” (Department of Health, 1995; Ehiri and Morris, 1995; Fowler, Statistical process 1994; Schothorst and Jongeneel, 1992). control in UK The HACCP system This system for food safety control was introduced into European food legislation under the EU Food Hygiene Directive 93/43/EEC in June 1993, and into the UK via the Food Safety (General Food Hygiene) Regulations, which took effect on 15 September 1995. The approach involves identifying, controlling and monitoring critical process areas where the safety (or quality) of a food product may be compromised. It covers the whole scope of a food processor’s operations (from growing, harvesting or slaughter through to final packing and consumption), and places the emphasis on prevention and control rather than the more traditional end-product testing (Codex, 1993b; Ehiri and Morris, 1995; Kirby, 1994; Miyagishima et al., 1995; Moy et al., 1994). Together with BS EN ISO 9000, with which it can be effectively combined (Miyagishima et al., 1995; Jouve, 1994; Spriegel, 1994), it has become “the internationally accepted approach for assuring the safety of food”, and an essential element of the “due diligence” defence (Moy et al., 1994).
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The HACCP principles The Codex Alimentarius Commission (CAC)[6], in its advisory monogram (Codex, 1993b), identifies seven principles for HACCP, summarised in Table I. Principle
Action
1
Identify potential hazards associated with food production at all stages. Assess the likelihood of occurrence of the hazard and identify preventive measures for their control
2
Identify points/procedures/operational steps that can be controlled to eliminate the hazard(s) or minimise the the likelihood of its occurrence (critical control point (CCP))
3
Establish target values and critical limits which must be met to ensure the CCP is under control
4
Establish a system to monitor control of the CCP by scheduled testing or observations
5
Establish the corrective action to be taken when monitoring indicates that a particular CCP is: (1) Out of control; (2) Moving out of control
6
Establish procedures for verification to confirm that the HACCP system is working effectively
7
Establish documentation concerning all procedures and records appropriate to these principles and their application
Table I. Seven principles of HACCP (modified from Codex, 1993b)
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The approach involves identifying the key process stages critical control points (CCPs) at which hazards (such as the multiplication of potentially harmful bacteria) may be introduced, and establishing control limits and/or targets at these points. On-line control is then implemented on the CCP, and records kept for monitoring, trend analysis etc. (Codex, 1993b; Ehiri and Morris, 1995; Miyagishima et al, 1995; Moy et al., 1994). Examples of such critical controls are pH levels (Ehiri and Morris, 1995), and heating/refrigeration temperatures (Kirby, 1994; Miyagishima et al., 1995) of food products at various stages in processing. The approach, almost analogous to Taguchi-style process “robustisation”, is designed to be applicable to any food manufacturing process. SPC and the HACCP system Although the Codex (1993b) guidelines do not make reference to SPC, the process of setting targets and limits for CCPs, and monitoring production against these on an on-line basis is exactly analogous to SPC control charting. Like BS EN ISO 9000, HACCP cannot make specific requirements for the use of SPC tools, since processes vary, as does the nature of their CCPs. Neither, it must be remembered, does it require the use of SPC. Nonetheless, the HACCP system provides an ideal framework onto which SPC methods can be applied, whether it be control charting, or acceptance sampling of incoming product/ingredients. The application of such methods will further assist the organisation by allowing it to systematically, predictably and (most importantly) demonstrably control the CCPs. A simple example of the above is the use of mean and range charts to monitor and control oven temperature and/or cooking duration, where heating of food has been identified as a CCP. Problems with implementation Ehiri and Morris (1995) report that food organisations have not embraced the HACCP strategy with the enthusiasm originally anticipated. Difficulties, the authors claim, are due to the voluntary status of the approach, coupled with a limited understanding of the strategy itself among operators. This applies particularly, as Kirby (1994) states, to small- and medium-sized enterprises (those with less than 500 employees), where there may also be insufficient technical resources. To whatever extent this is the case with HACCP, it is likely to be equally if not more true with regard to the understanding and application of SPC techniques. The model of a fully operational HACCP system coupled with SPC on the CCPs therefore represents something of a holy grail. Weights and measures legislation This second key area of legislation applies to most organisations which pack goods (not just food). It has more concrete and specific implications relating to appropriate SPC systems and procedures, details of which are provided in the Code of Guidance produced by the Department of Trade and Industry (1979a), although adoption of such techniques is again non-mandatory.
The average system Statistical process Under European law, certain packaged goods, which include drink and control in UK foodstuffs, must conform to the average system, which replaced the “minimum food production system” on 1 January 1980, being introduced under the Weights and Measures Act. The system applies to any food “package” (this being defined as the combination of a container and the goods it contains) which contains goods prescribed by the regulations which are either: 227 (1) subject to any lower or upper quantity limits, or; (2) marked with the “e” mark and bear a quantity marking within the range 5g to 10Kg (or 5ml to 10L). The declared weight or volume of package contents is known as the “nominal quantity”, often accompanied on the packaging by an “e”-mark, which, although not obligatory, is a guarantee recognised throughout the EU that the goods to which it applies have been packed in accordance with the relevant EU directive. If the actual contents of any package are less than the stated nominal quantity, the difference is referred to as negative error. For any given weight or volume there is an associated tolerable negative error (TNE), which represents a permissible amount by which some packages may be underfilled. The TNE values for a given quantity are available from a published table, reproduced in Table II. Nominal quantity (Qn) g or ml 5-50 50-100 100-200 200-300 300-500 500-1,000 1,000-10,000 10,000-15,000 Above 15,000
Tolerable negative error (TNE) As percentage of Qn g or ml 9 – 4.5 – 3 – 1.5 – 1
– 4.5 – 9 – 15 – 150 –
The Act is enforced in the following way. For any given sample of packages taken for testing by a trading standards officer (TSO), the following three rules must be satisfied; otherwise an offence will have been committed under the Weights and Measures Act: Rule 1: The actual contents of the packages shall be not less, on average, than the nominal quantity. Rule 2: Not more than 2.5 per cent of the packages may be non-standard i.e. have negative errors larger than the TNE specified for the nominal quantity.
Table II. Tolerable negative errors (DTI, 1979a; 1979b)
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Rule 3: No package may be inadequate, i.e. have a negative error larger than twice the specified TNE. The process of testing packages for compliance with the average system under the three rules for packers is known as “reference testing”. This involves the TSO drawing a sample from a range of packages at a retailer’s premises (informal reference test), or from the packing facility itself (formal reference test). For the formal test, packages are normally taken from an hour’s production (using on-line sampling with a random number generator selecting the elements) or from a batch of not more than 10,000 packages from the same production run, from stock. The officer merely checks the sample taken against the above three rules for packers (DTI, 1979b). Ensuring compliance: SPC and the average system Though apparently simple, these rules have far-reaching ramifications for a packer’s control systems in ensuring that all three requirements are met for any sample which may be taken. There are two basic methods which organisations use to ensure compliance. The first method is to pack or produce to a mean target weight which is higher than the declared nominal quantity. This method will necessarily result in a high level of product “giveaway”, where packages are overfilled at the expense of the packer. In many cases where the product is relatively inexpensive, this is not seen as a problem, and despite its obvious drawbacks, overfilling is not uncommon. Some bakeries which produce bread and flour confectionery use this method, since the raw materials involved are relatively inexpensive. There are, however, two problems with this approach. First, any significant overfilling is itself an offence under the Act, and second, while a sufficiently high mean weight can be ensured this way, if process variance is not monitored, then more than the permitted proportion of packages may fall below minimum TNE values. Although it is likely that these will be picked up and rejected during final checkweighing of the package prior to storage or shipment, if undetected, they will constitute an offence under the Act and against the consumer. The second method involves the use of SPC to routinely monitor and control the mean and variability of package quantities. This involves: • accurately assessing short-term and medium-term process standard deviation (denoted so and sp respectively) via a process survey; • using sp and the properties of the normal distribution to obtain a target weight setting which will just satisfy all three packers’ rules for all samples under normal production; and • then using mean and range (or s o ) based control charts to monitor subsequent production runs. To assist the producer with this, the DTI (1979a) manual provides detailed advice on proper sampling methods, correct and accurate calculation of so and
sp, and construction of the relevant control charts. Without some element of Statistical process statistical training, however, it is no trivial matter for the quality or technical control in UK manager to understand, interpret and apply the advice given in this document. food production It may also be for this reason that some producers merely opt for the former strategy of overfilling. Empirical research To gain an overview of the nature and extent of SPC usage among UK food companies, a survey, with follow-up interviews (case studies), was conducted on a sample of 200 organisations of various size and specialism. The survey objectives were: (1) To establish the extent to which the producers are applying the techniques of SPC within their routine manufacturing operations. (2) To identify the most common techniques used, the scope of usage, and the normal sources of information used in setting up the systems. (3) To investigate whether such systems are found to be beneficial to organisations, and whether there is a need for more to be done to promote use of SPC within the industry. Methodology Companies were selected from a directory of British food companies (Turner, 1996), with questionnaires only being sent to companies involved in the manufacture and/or packing of produce (as opposed to those who only distribute or retail). There are ten standard industrial classification (SIC) groups within the food industry which are of interest under the above criteria, and within these, the largest two to three firms typically account for upwards of 50 per cent of the overall market share (Burns and King, 1993). Each sub-sector was represented, with the largest companies included wherever possible. The survey excluded manufacturers of drinks and beverages, and very small labour-intensive enterprises (any with less than ten employees, high street butchers, cake decorators etc.). For the sake of reliability replies were kept anonymous, but respondents were requested to state the size of their firm, number of sites, and main specialism for purposes of analysis. Results of the survey Responses were received from 71 separate processing sites, and results are summarised in Figures 1-4. Responding organisations ranged in size from small independent companies with around 40 employees, to large multi-site facilities employing several thousand, in some cases tens of thousands. A tripartite categorisation dividing companies into small, medium or large size on the basis of number of employees has been used. Considered together, slightly under half (45 per cent) of the responding organisations make use of SPC techniques, and, as might be
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Figure 1. General information
Total Sites OPERATIONS Processing/Mfg Packing SIZE Small (10-99) Med (100-499) Large (500+) SPECIALISM Bread, Biscuits & Flour Sugar Confectionery Animal & Fish Products Prepared Foods Ingredients/Mixes Milk and Dairy
Key All Sites Sites using SPC
0 10 20 30 40 Number of Respondents
50
60
70
80
expected, the relative proportion of organisations using SPC increases with organisation size. Use of SPC is present in all categories represented[7] among the responses, although a sub-sectoral breakdown of the industry is outwith the scope of this article. Figure 2 shows information relating to the organisations quality systems. As shown, 69 per cent of organisations have a quality or technical manager, and 86 per cent indicate having a quality system in place. Only 23 per cent have, or are working towards, registration to BS EN ISO 9000, due mainly to the fact that most supply only to the consumer. Many organisations make use of SPC, but consider BS EN ISO 9000 unnecessarily burdensome (60 per cent of those using SPC), which situation is illustrated in Case 1 below. Most quality systems relate primarily to food safety, which is to be expected, since such a system is mandatory, and provides evidence for the due diligence Total Sites Quality Manager Quality System BS EN ISO 9000 Yes In Process No Unnecessary QA SYSTEM Weights & Measures Food Safety Figure 2. QA information
Key All Sites Sites using SPC
0 10 20 30 40 Number of Respondents
50
60
70
80
defence. Only a small proportion of producers use SPC in these systems, which Statistical process reflects the relative lack of guidance literature in this area, as mentioned control in UK previously. In contrast to this, although relatively fewer quality systems relate food production to the control of weights and measures, a far larger proportion (almost all SPCusers), make use of SPC in this area. The reason is conversely that there is quite specific guidance available on using SPC for such systems (DTI, 1979a). This is 231 amplified in Figure 3, which shows that over half (56 per cent) of all SPC users have obtained their system from this publication, with 25 per cent using other sources, such as BS 6001 covering acceptance sampling. As Figure 3 also shows, the most common techniques are Shewart mean and range (or standard deviation) charts, while use of attribute control charts, acceptance sampling and process capability studies is generally less widespread. Again, this may be due to relative lack of industry-specific guidance on these methods. SPC is not commonly used for incoming material control, and tends to be used mostly for in-process and packaging control. All these organisations provide training, evenly comprising formal and informal approaches. With regard to the use of software packages, 66 per cent of the SPC users make use of software to help with analysis. Of these, only four use dedicated offthe-shelf QA or statistical packages, most preferring the spreadsheet or other custom-written programs, presumably owing to the perceived relevance of such software to their own systems and processes. This indicates that although there is a range of dedicated SPC packages, companies lack the necessary in-house expertise to make effective use of these. Finally, but perhaps most importantly, all but two responding organisations who use SPC reported that they find it beneficial to the organisation. The stated benefits are summarised in Table III. Eight companies indicated that they would like more information on SPC, and help with establishing systems, of these, three are existing users who would like to make more effective use of the techniques. These cases are of most interest to this study, and are represented by Case 3 below. Case studies Follow-up interviews indicated three main approaches to SPC taken by organisations in the sector, these being: companies who apply SPC to some or all processes; those who do not consider it necessary; and those who recognise its potential benefits, but are unable to implement due to lack of necessary skills or personnel. The following three cases, taken from sample elements, typify these approaches. Case 1: “we can, and we do” The first interviewee is a small to medium sized organisation with around 50 employees, involved in the manufacture of fish products. The organisation supplies both small and large retailers. The quality manager, having successfully implemented ISO 9002, is now phasing this out, owing to the large
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232
Mean Charts Range Charts Std Dev Charts Attribute Charts Process Capability Acceptance Sampling SPC SCOPE Goods Inward In-Process Final Packing TRAINING Formal Informal Formal and Informal OTHER INFORMATION Find SPC Beneficial Use Software
Figure 3. SPC user information
0 5 10 15 Number of Respondents
20
25
30
35
amount of “unnecessary” paperwork which this generates, but remains convinced as to the benefits of SPC. The organisation’s SPC activities, derived from the DTI (1979a) manual, are centred around the control of weights and measures and extend to the use of mean and standard deviation(s) charts to control package weights. Operators and controllers, although not statistically trained, simply follow written procedures. The procedures specify sampling intervals, sample size, necessary calculations for control chart limits, and the corrective action(s) to be taken in the event of an out-of-control signal, e.g. thickening or thinning batter, or
Reported benefit Reduction of “giveaway”/waste reduction Improved in-process control Compliance with average system requirements Improved customer quality assurance Process capability assessment/limit setting Ease of trading standards inspection Improved packaging efficiency Process improvement Improved employee awareness
Number of respondents
Percentage
13 8 7 5 3 2 2 1 1
41 25 22 16 9 6 6 3 3
varying the quantity of fish. All activities are manual, including data collection, calculation of means and SDs, and plotting data on control charts. The organisation has no means of computerising these activities, as no employee is sufficiently trained in statistics or IT trained to operate statistical software, or to write their own custom package. The necessary investment in hardware, software or training is moreover considered an unnecessary expense, since the system operates effectively at present. The organisation reports the normal benefits of reduced “giveaway”, increased custom (from the assurance provided by demonstrable use of Shewart charts), and ease of external inspection, since records are methodical and readily available. In terms of limitations of the system, because of the lack of statistically trained staff, the procedures, although perfectly adequate on a working level, fall short of the full recommendations within the DTI manual with regard to the establishment of an accurate measure of medium-term process variance, for which it recommends using large data sets, collected over longer periods of time, on an infrequent basis (after a significant change to a process, or on establishment of a new process). The system is, however, practical and workable, and perfectly adequate for its purpose. Case 2: “we can, but we don’t” The second case concerns a large bakery which supplies its own chain of shops. This organisation produces a wide range of produce, which it supplies to a network of local retailers. The organisation employs around 650 people (exclusive of those in high street shops), and has a quality manager. Although dedicated to TQ principles, it has decided not to implement ISO 9000, which it considers unnecessary, and it has also not implemented any form of SPC for the same reason. The control of weights and measures is in this case achieved through a higher than specified average fill, i.e. loaves of bread might be produced to a declared weight of 800g, but the process is set to exceed this amount, thus ensuring no underweight items.
Statistical process control in UK food production 233
Table III. Pareto analysis of reported benefits
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The manufacturing methods in this organisation are largely traditional in nature, which provides much of the appeal of its products. The organisation therefore sees no need to institute SPC since they are financially successful, the ingredients are inexpensive (compared to meat products, for example) and their system, such as it is, succeeds in satisfying the legislation. The problem of giveaway (as mentioned above) is acknowledged, but offset against the time, effort and cost involved in implementing SPC procedures “from scratch”. In these respects, the organisation is typical of many in the industry. The author was not surprised to note, however, that just prior to his visit to these premises, a complaint about overfilled bread had led to a visit from trading standards. Case 3: “we want to, but we can’t” The third case is a high volume production facility which is part of a much larger UK organisation. The organisation has several such facilities, some of which use extremely rigorous SPC procedures. The location visited was, however, experiencing problems with the implementation of SPC, due simply to a lack of available in-house expertise. Experts from another of the sites had visited and had established procedures some time previously and SPC software had been bought in to help with the task, but ultimately the factory had lacked the knowledge base to fully understand and implement the procedures, and had subsequently abandoned them. It was, nonetheless, recognised that the procedures should be implemented, and (at the time of writing), work is ongoing using assistance from local universities. This case highlights a typical problem experienced by food companies. The sector has traditionally concentrated on employing individuals with expertise in the specific manufacturing processes, and in general principles of food technology, microbiological food safety control, etc. It has not previously been the case that these individuals are also trained in areas such as statistical methods or general operations management. For the non-statistician, the DTI manual is a difficult document to understand and interpret, and many companies only use it as far as obtaining the necessary TNE values. The system then extends only as far as setting a mean filling level high enough that the three rules are met, and nothing more. Conclusions First, although not a mandatory requirement in the food industry, SPC can prove beneficial to organisations in the sector regardless of their particular specialism and size. This comes across in the positive comments received from organisations using SPC (Table III). It has a substantial role to play in the quantity control, and to a varying degree in food safety control, although this is more difficult to apply, in the absence of specific guidance literature. It is important to bear in mind that small, manually-driven systems can prove as effective as hi-tech, automated ones, so SPC-based control systems need not be expensive to set up. There is also no particular need to source statistical
software, as manual charts can be just as effective, and can enable operators Statistical process and other users to understand the mechanics of the system. control in UK Second, the efficacy of SPC appears to be to some extent a function of product food production range. Expensive products such as meat, fish, chicken etc. have a large operating cost associated with “giveaway”, making statistical quantity control relatively more critical or attractive to companies dealing with such produce 235 than to others for whom the product is inexpensive, or easily reusable. Similarly, some products are less safety-critical than others. For these reasons, certain organisations perceive SPC as more beneficial than others who may be unconcerned with making the necessary investment. The organisations most in need of assistance are those who are unable to make use of SPC, although they perceive benefits from so doing, and those who feel that they could be making more use of it than they are, but lack the necessary guidance. For these organisations, the best way forward, besides consultancy, is most likely to be through some combination of the following initiatives: (1) Training of new graduates/diplomates entering the industry in the principles of QA principles and statistical methods. (2) Training the existing workforce and management in interpreting the relevant literature, and applying statistical control procedures to processes. (3) Upgrading the available guidance literature to produce something more specific. The role of academic institutions The process of educating the next generation of food industry management has begun within tertiary education, with more courses of study in the food area covering elements of quality assurance and SPC[8]. Organisations involved in the survey described in this paper were asked for their attitudes towards these skills in new graduates. As summarised in Figure 4, most believe them to be desirable qualities. The academic sector can further assist the sector through the provision of short courses for existing management and operators, to update their knowledge of these aspects. Teaching company programmes The establishment of teaching company programmes represents one of the most effective methods for higher education to assist the food industry in exploring the potential of SPC and other such techniques. In these programmes, graduates (known as “associates”) are employed by the higher education institution (HEI) and seconded on a full time basis into the partnered organisation for a period of two years, during which time they undertake a project of potentially significant benefit to the organisation. In this way, the HEIs can provide expertise and “technology transfer” at minimal cost,
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Figure 4. Education/training developments – industry perceptions
Key Very useful Quite useful Not useful Unsure
Development of NVQs in Stats/Quants
Stats/Quants ability in new graduates
Knowledge of TQM principles in graduates
0 5 10 Number of Respondents
15
20
25
channelled through graduates who can develop high levels of practically-based expertise in the area. National vocational qualifications Regarding training existing staff, these awards, regulated by the National Council for Vocational Qualifications, once incorporated into an organisation’s training schedule, can be used to provide demonstrable fulfilment of quality system training requirements. As Thomson (1995) reports, it is likely that they will become important references of competence and performance, necessary for the demonstration of the “due diligence” defence. While development work into NVQs in the food processing sector is on-going, it will be useful if institutions and bodies involved in this process are aware of the need for the qualifications to contain an appreciation not just of quality assurance in general, but of SPC and its potential role within HACCP and the average system, so that industry may begin to establish higher levels of expertise and awareness among existing operational staff. As Figure 4 shows, many organisations are unsure about the efficacy of these, but most again favour the introduction of such methods. The role of the Government Miyagishima et al. (1995) suggest that workers, directors and management should fully understand the importance of food safety assurance, and that the Government has a role to play in such dissemination. This they believe can be achieved through the implementation of a national plan of action for nutrition, incorporating the twin aspects of quantity and quality aspects of food, and involving: • Development of a national food safety policy. • Development and extension of legislation and enforcement.
• Promotion of voluntary quality assurance. Statistical process control in UK • Education of workforces. food production • Applied research. It is certainly the case that while the DTI (1979a) publication is widely used in the establishment of SPC for quantity control, there is less available adequate 237 guidance on where SPC might be used for food safety control, and other potential areas of application. Notes 1. Escherichia coli. 2. In England and Wales, some aspects of food safety legislation are also enforced by trading standards officers. 3. These criteria include microbiology, chemistry, toxicology, immunology, veterinary medicine, epidemiology and many others. 4. Campden Food & Drink Research Association. 5. Bacon and Meat Manufacturers Association. 6. An organisation comprising the Food and Agriculture Organization of the USA (FAO) and the World Health Organization (WHO). 7. Some of the categories used are “catch-alls” including a degree of further diversity, such as “prepared foods”, which includes canned foods, pasta, chilled foods, ready meals and sandwiches. These have been used to simplify the analysis. 8. Glasgow Caledonian University offers two such programmes, being the BSc in Food Technology, and the BA in Consumer and Management Studies (food product development route). References Burns J. and King R. (Eds) (1993), Training in the Food and Beverages Sector in the United Kingdom, European Centre for the Development of Vocational Training, Berlin. Cheng, T. (1994), “A quality improvement study at an aerospace company”, International Journal of Quality & Reliability Management, Vol. 11 No. 2, pp. 63-72. Chiu, H.-N. and Huang, B.-S. (1996), “The economic design of x control charts under a preventive maintenance policy”, International Journal of Quality & Reliability Management, Vol. 13 No. 1, pp. 61-71. Codex (1993a), Procedural Manual, Codex Alimentarius Commission, FAO, Rome. Codex (1993b), Guidelines for the Application of the Hazard Analysis Critical Control Point (HACCP) System, Codex Alimentarius Commission, FAO, Rome. Department of Health (1995), Food Safety (General Food Hygiene) Regulations, HMSO, London. DTI (1979a), Code of Guidance for Packers and Importers, Department of Trade and Industry, HMSO, London. DTI (1979b), Manual of Practical Guidance for Inspectors, Department of Trade and Industry, HMSO, London. Ehiri, J., Morris, G.P. and McEwan, J. (1995), “Implementation of HACCP in food business: the way ahead”, Food Control, Vol. 6 No. 6, pp. 341-5. Fowler, B. (1994), “The new food regulations”, Quality World, Vol. 20 No. 10, pp. 686-7. Gaafar, L. and Keats, B. (1992), “Statistical process control: a guide for implementation”, International Journal of Quality & Reliability Management, Vol. 9 No. 4, pp. 9-20.
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