orid Health Organization / ` °,
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The World Health Organization is a specialized agency of the United Nations with primary responsibility for international health matters and public health. Through this Organization, which was created in 1948, the health professions of more than 150 countries exchange their knowledge and experience with the aim of making possible the attainment by all citizens of the world by the year 2000 of a level of health that will permit them to lead a socially and economically productive life.
The WHO Regional Office for Europe is one of six Regional Offices throughout the world, each with its own programme geared to the particular health problems of the countries it serves. The European Region has 33 active Member States,' and is unique in that a large proportion of them are industrialized countries with highly advanced medical services. The European programme therefore differs from those of other Regions in concentrating on the problems associated with industrial society. In its strategy for attaining the goal of "health for all by the year 2000" the Regional Office is arranging its activities in three main areas: promotion of lifestyles conducive to health; reduction of preventable conditions; and provision of care that is adequate, accessible and acceptable to all.
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a Albania, Algeria, Austria, Belgium, Bulgaria, Czechoslovakia, Denmark, Finland, France, German Democratic Republic, Federal Republic of Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Monaco, Morocco, Netherlands, Norway, Poland, Portugal, Romania, San Marino, Spain, Sweden, Switzerland, Turkey, USSR, United Kingdom and Yugoslavia.
Cover: The Wedding Feast by P. Bruegel the Elder.
Reproduced by kind permission of Kunsthistorisches Museum, Vienna.
World Health Organization Regional Office for Europe Copenhagen
Mass catering
R.H.G. Charles
Senior Medical Officer Department ofHealth and Social Security London, United KingdomWHO Regional Publications, European Series No. 15
ISBN 92 890 1106 8
© World Health Organization 1983
Publications of the World Health Organization enjoy copyright protection in ac- cordance with the provisions of Protocol 2 of the Universal Copyright Convention.
For rights of reproduction or translation, in part or in toto, of publications issued by the WHO Regional Office for Europe application should be made to the Regional Office for Europe, Scherfigsvej 8, DK -2100 Copenhagen 0, Denmark. The Regional Office welcomes such applications.
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The mention of specific companies or of certain manufacturers' products does not imply that they are endorsed or recommended by the World Health Organiz- ation in preference to others of a similar nature that are not mentioned. Errors and
omissions excepted, the names of proprietary products are distinguished by initial capital letters.
The views expressed in this publication are those of the author and do not necessarily represent the decisions or the stated policy of the World Health Organ- ization or of the Department of Health and Social Security, London.
TYPESET IN INDIA PRINTED IN ENGLAND
CONTENTS
Page
Foreword vii
Acknowledgements ix
Introduction 1
Bibliography 2
1. GENERAL PROBLEMS 3
Contamination 3
Premises 5
Supply of raw ingredients 7
Hygienic practices 8
Workforce 10
Nutrition I 1
Bibliography 13
2. GENERAL METHODS OF CONTROL 15
Planning and licensing 15
Management and inspection 16
General hygiene 17
Raw material 18
Laboratory tests 19
HACCP 21
Water 22
Personal hygiene 23
Epidemiology 24
Bibliography 25
3. RECENT TECHNOLOGY 27
Cook -freeze and cook -chill 27
Slow cookers 28
Microwave cooking 28
Convenience foods 29
Electronic thermometers 29
Anaerobic packing 31
Bibliography 31
v
4. TRAINING 33
Bibliography 35
5. INSTITUTIONAL AND WELFARE CATERING 37
Hospitals 37
Schools and old people's homes and clubs 38
Meals -on- wheels 40
Bibliography 41
6. CANTEENS IN FACTORIES AND OTHER
COMMERCIAL ESTABLISHMENTS 43
7. OPEN AIR CATERING 45
Disasters 45
Festivals 47
Bibliography 48
8. TOURIST HOTELS AND HOLIDAY CAMPS 49
Bibliography 51
9. TRAVEL CATERING 53
Aeroplanes 53
Ships 56
Other vehicles 59
Bibliography 60
10. OTHER CATERING FOR TRAVELLERS 61
11. BANQUETING 65
12. SUMMARY 69
Foreword
With the increase in urbanization, industrialization and tourism, mass catering systems are becoming increasingly popular throughout the world in both industrialized and developing countries. They provide a convenient and economical means of catering for large numbers of people. Traditional forms of catering have been associated with many outbreaks of food poisoning and other foodborne disease in the past. Mass catering operations, by reason of their scale and complexity, have the potential to produce even more disastrous consequences for health, if the strictest principles of hygiene are not maintained. Since mass catering may account for much of the dietary intake of large sections of the population,
particularly of highly vulnerable groups such as children and the elderly, careful nutritional surveillance is necessary. Because of the health implications of mass catering, it is important that both the health authorities and other officials and commercial interests should be aware of the problems. Staff employed in catering should understand what they need to do and why, and it is the responsibility of the food safety authorities to provide adequate training facilities. This book is therefore intended for health officials who have little knowledge of commercial catering, and for food, trade and other officials and commercial interests that have little knowledge of public health. It does not set out to be a technological manual or a text book of food hygiene or the epidemiology of foodborne disease. Its aim is to draw attention to the relationship between mass catering and public health and to show where further information can be found.
While many of the principles of hygiene, food safety and nutrition are common to all forms of catering, many systems of mass catering and situations in which mass catering is employed present their own peculiar problems. This book therefore starts by dealing with the general aspects of public health in relation to catering, planning, monitoring and training, and then goes on to deal in subsequent chapters with the specific problems of particular aspects of catering, such as travel catering, institutional catering, banqueting and so on. A selected bibliography of useful reference books and papers for those who require more information about the subject appears at the end of most chapters.
vii
On behalfof WHO I wish to thank all those experts in many countries who have assisted Dr Charles in the preparation of this book, and particularly those in Bulgaria, the Federal Republic of Germany and Sweden who so kindly arranged and took part in visits by the author and his collaborator, Mr Hughes.
"Der Mensch ist, was er isst"
Feuerbach
Leo A. Kaprio WHO Regional Director for Europe
Acknowledgements
The author wishes to express his thanks for all the assistance he has been given by friends and colleagues in government service and the catering industry in many countries, especially Professor Shindolev, Professor Kaloyanova, Professor Efremov, Dr Stroeva
and Dr
Gheorgiev in Bulgaria, Dr Kobbe in the Federal Republic of Germany, Dr Florin and Dr Augustinsson in Sweden, Mrs Cynthia Sadler for the illustrations and Mrs Maureen Simpson for all her invaluable help.
He particularly wishes to express his gratitude to Mr H. L. Hughes, Environmental Health Officer, late of the Department of Health and Social Security, who collaborated closely in this work. Not only did Mr Hughes assist with his wide knowledge and experience, but also visited Sweden and the Federal Republic of Germany for the author.
ix
Introduction
It is becoming increasingly common for people to come together in large numbers, usually outside their own homes, for medical care, social
activities, education, employment, etc. and in
the course of these
activities to eat food that they have not prepared themselves. This is seen to the greatest extent in the industrialized countries. For example, it has been estimated that in 1976 in the Federal Republic of Germany at least 20 million people regularly had meals outside the home. Of all expenditure on food in the United Kingdom one sixthis on food
prepared outside the home. With the increase of urbanization, industrialization, mass travel and tourism in the developing countries, similar trends in eating habits are beginning to appear there.
Such eating habits may be associated with many very different human activities, in factories, schools and hospitals, on ships and aeroplanes, at arts and music festivals and tourist hotels, in cafeterias, and at take -away premises, wedding receptions and formal banquets. All these different activities have at least one thing in common: they increasingly demand the provision of food in a form that is ready to be eaten by a large number of people at the same time, or within a period that is relatively short in relation to the numbers to be fed.
This demand cannot be met economically by traditional forms of catering. In traditional catering, the meals are individually ordered for one customer, or at most a small group of customers, and are prepared at the time of ordering and served with very little delay. In contrast with this, modern catering requirements make it necessary for large quantities of food to be prepared in advance of demand and served rapidly, indeed almost simultaneously, to a large number of people. The food may also
have to be served at more than one outlet, often at many outlets distributed over a wide area. The advanced technology and the
expensive and specialized equipment usually needed for the satisfactory production of food in bulk may make it more economical to prepare all the food at a single central kitchen.
To use this equipment and trained staff efficiently and cost -effectively it may be advantageous to have a continuous operation throughout the
working day. The importation of new technology and intensive
centralized food production may create serious difficulties in countries that lack the appropriate technological and sanitary infrastructure. In any country, centralized food production may lead to long delays between cooking and eating. There may also be a considerable distance between the place where the food is cooked and the places where it is to be served and eaten. Special precautions are needed during storage and distribution to keep the food both safe and appetizing.
The term "mass catering" is conveniently applied to all these techniques
of bulk preparation and cooking of food, which are
performed without prior consideration of each individual consumer. The term "time -shift catering" is used to describe systems that embody an interval of more than two hours, and often several days or weeks, between cooking the food and serving and eating it. The different situations in which mass catering is employed have similar basic requirements. They may also have their own specific problems, which will be considered in the appropriate chapters.
Bibliography
King, S. Eating behaviour and attitudes to food, nutrition and health.
London, British Nutrition Foundation, 1981.
Economic Commission for Europe & Food and Agriculture Organization of the United Nations. Proceedings, Symposium on Technical and Economic Aspects of Catering, Budapest, 20 -23 April
1982. Budapest, Hungarian Central Technical Library and Documentation Centre (in press).
2
1
General problems
Contamination
In mass catering, as in all catering, the most important problem is that of ensuring that the food does not injure the health of the consumer.
Food becomes harmful because of the presence of undesirable chemical or biological agents. Some harmful biological agents are disease -causing bacteria such as the food poisoning salmonellae or the dysentery organisms, parasites such as the tapeworms or Giardia spp., or viruses such as those causing infective jaundice. Other biological agents are toxins produced in food by bacteria such as Staphylococcus aureus and Clostridium botulinum, or occurring naturally in the living animal or plant such as algal poison in shellfish or the toxins in some fungi.
Chemical poisons may enter plants and grazing animals from the environment; they may be present naturally, as lead in some soil, or may be caused by industrial pollution. Contamination of food or animals with synthetic chemical substances may follow accidental environmental pollution or their deliberate use as insecticides or growth -promoting antibiotics. If these are used without proper control, undesirable levels of residues will be found in the food. Contamination can also occur if food is stored where it comes into contact with poisonous substances, or if poisonous metals dissolve from the surface of food containers or equipment. There are frequent reports from all over the world of outbreaks of acute poisoning due to the storage of acid foods, such as cooked fruit, in copper containers or lead -glazed vessels, from which
some of the metal has dissolved into the food.
A serious outbreak of liver disease occurred some years ago in England, following the consumption of bread made from flour that had accidentally become contaminated with fungicide carried in the same lorry. The deliberate adulteration of food with cheaper substances can be a hazard to health if the adulterants are harmful. Sometimes, as happened in Spain in 1981, even the perpetrators of the fraud may not be aware that the adulterants contain highly poisonous substances.
Properly produced raw food ingredients should be free of undesirable levels of chemical additives and contaminants. Harmful microorganisms are constantly present in the environment or in food animals themselves,
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and it must be assumed that they will be present in all raw food. This is true even when the food comes from the most modern and apparently hygienic farms or slaughterhouses. At this stage it is rare for microorganisms to be present in sufficient numbers to cause illness. The few that will cause illness even in small doses, for example the typhoid bacillus or the hepatitis virus, are inactivated by cooking and often by other processes used in food preparation such as pickling and curing.
There are some microorganisms, however, that will survive normal cooking, such as the spores of C. botulinum and C. perfringens, but these do not cause illness unless they can grow in the food. Food can be contaminated with harmful organisms after cooking, sometimes from an infected food handler, but much more often directly or indirectly from raw food. This is usually only a question of small numbers of organisms, and the food remains safe if it is held at temperatures at which the contaminating organisms are unable to increase and reach an infective dose or produce toxins in the food. To prevent the activity of dangerous microorganisms, food should be kept at a temperature above 60 °C or below 10 °C. If the food is to be kept cold for more than 6 hours it should be below 5 °C. Fish should ideally be kept below 3 °C since the type of C. botulinum found on fish, type E, will grow slowly at temperatures over about 3.5 °C. At these low temperatures and under normal conditions, psychrophilic spoilage organisms grow faster than
C. botulinum and make the fish unpalatable before it becomes
dangerous. If the fish is partially cooked or cured, however, these spoilage organisms may be destroyed or unable to grow and will not therefore give an indication that the food is unsafe to eat.
The scale of mass catering means that workers, food handling practices, equipment and premises must reach the highest standard of hygiene that can reasonably be obtained.
Premises
Many catering premises are not purpose -built and, though satisfactory for small -scale catering, cannot be adequately adapted to the larger scale and different techniques of mass catering. However prestigious or long established an hotel or restaurant may be, mass catering should not be undertaken there unless there is certainty that it
can be done
satisfactorily. Mass catering cannot be performed safely merely by increasing the size or quantity of the type of equipment traditionally used in conventional kitchens for the preparation of individual dishes.Only properly designed equipment is satisfactory for bulk cooking. It is not adequate to have domestic types of cooker on which large pans have to be balanced across several burners or heating elements; instead, cookers with solid continuous tops should be provided. Rather than
locally modified large saucepans and frying pans, there should be heavy - duty commercial steamers, pressure cookers and bratt pans. Forced -air convection ovens are usually essential for the proper cooking of large poultry carcasses and joints of meat. Equipment for the accurate
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6
monitoring of the time and temperature of cooking helps to ensure thorough cooking while minimizing the
loss of nutrients and the
expenditure of energy. All equipment must be designed to be cleaned thoroughly and frequently. There must be appropriate and sufficient storage facilities for raw ingredients and for cooked food, refrigerated if necessary. When new premises are planned fora mass catering
operation, the site should be carefully chosen. It should lend itself to the hygienic layout and construction of the premises and should have easy access for supplies and employees. Appropriate sanitary services should be readily available.
Economic and cultural factors may influence the choice of site, for example a remote area of great natural beauty that is attractive to tourists, a traditional centre of mass recreation or entertainment, or an industrial area where there are rail, road and power facilities and a large number of factory workers close at hand to provide an immediate market for the catering services. Industrial areas may, however, present problems of contamination from fumes and smoke, while remote rural areas, particularly in some developing countries, may lack an adequate sanitary infrastructure for a large -scale food manufacturing operation.
Supply of raw ingredients
There should be an adequate supply of raw materials of satisfactory quality; this can impose a serious strain on the local food supplies. The pressure to increase food production may lead to the use of undesirable amounts of natural or synthetic fertilizers
and manures, and of
pesticides and growth -promoting substances. These can all cause increased chemical or microbial contamination of food. While raw food containing infectious microorganisms can usually be made safe by thorough cooking, there is very little that can be done with food that is contaminated with undesirable chemical substances or that contains residues of such substances as pesticides or antibiotics. This can only be avoided by proper control and by the intelligent and informed use of such substances. To achieve this the national government must establish an appropriate organization for the control of these substances and must provide proper advice and instruction for farmers and agricultural
workers.
The manager of a mass catering establishment must be prepared to exercise some form of quality control over the raw materials that he buys. If necessary he may have to lay down commercial specifications for his suppliers and develop some laboratory or other means of checking that these specifications are met. This becomes even more important if he is buying -in partially prepared ingredients that have not been processed under his direct control. He may have to buy such ingredients routinely or he may buy them only as a temporary expedient to meet unexpected demand.
7
Hygienic practices
In many countries the supply of suitably skilled workers is insufficient, leading to the use of a high proportion of unskilled workers who need careful training and skilled supervision. Many mass catering systems use relatively advanced technology and require standards of hygiene that may be unfamiliar to the traditional food workers in some countries.
The manager must at all times ensure that all workers understand and maintain the general principles of food hygiene, cleanliness, adequate cooking, avoidance of contamination, and proper conditions for the
storage of raw and prepared food.
These problems apply to any industrial food manufacturing operation, but large -scale catering operations are particularly hazardous because of the nature of the food produced and the way it must be stored and handled for rapid service. Most of the food prepared by mass catering establishments readily permits the growth of microorganisms if held in the temperature range that those organisms require. Between 1970 and 1979 in England and Wales, of 1044 carefully analysed outbreaks of food poisoning 67 % were caused by food produced on a large scale; in more than 60 % of the outbreaks the food was prepared at least half a day before consumption and underwent inadequate temperature control.
Mass catering establishments provide not only food that is generally
perishable but also food that is eaten at the same time by a large
number of people. The consumers have little or no choice in, or controlover, the preparation or serving of this food.
The consumers may often be physically very vulnerable, for example children, the elderly or hospital patients. Other consumer groups may be economically sensitive, such as workers in an essential industry. A large outbreak of food poisoning in a factory canteen can temporarily, but completely, shut down a factory that may be vital to the economy of the
region or even the country. In addition to the immediate loss of
production, the delay in delivery dates may cause loss of contracts or of whole markets, which it may take a long time to regain. Travellers and holiday- makers are another economically important group: an outbreak of food poisoning on an aeroplane or in a tourist hotel can easily give that airline or tourist area a bad reputation. This may seriously damage its use by tourists and other travellers who are very important as a source of foreign currency for many countries. Furthermore, it may be necessary to pay large sums in compensation to holiday- makers whohave had their holidays ruined, or to businessmen who have lost
contracts because of illness.Convenience in the supply of raw material or in preparation and handling makes certain types of food popular for use in mass catering.
These foods may, however, present particular hazards. Frozen meats and poultry are convenient to store and supply in large quantities but they can be difficult to thaw satisfactorily and to cook properly. The intensive rearing of food animals may be necessary to produce sufficient
8
quantities of meat of a consistent size and quality for large -scale food preparation. It does, however, seem to increase the risk that the food animals, particularly poultry, will carry food poisoning microorganisms.
Boned rolled joints of meat are convenient for cooking and carving into identical portions, but the operation of removing the bone and rolling the meat will transfer microbes from the surface to the centre of the joint, where they are better protected from the heat of cooking.
Cooked meat and poultry are sliced more easily when they are partially cooled. If this delays complete cooling, pathogenic organisms may grow and survive to cause food poisoning, especially if the food is not then adequately reheated before serving. Indeed, when food is intended to be reheated, it may not be completely cooked in the first place, so as to avoid over -cooking when reheated. To prevent the growth of surviving microorganisms, it is essential to cool the food quickly and to store it at a safe temperature. Very large joints of meat are extremely difficult to cook or cool satisfactorily.
When hot meals are prepared for immediate consumption by heating canned food or commercially produced ready -to -serve frozen foods, it is unusual for health problems to arise. On the other hand cold foods, especially elaborate cold buffets, require the greatest care if safety is to be ensured.
Some aspects of mass catering demand that very large quantities of food are served in a very short time, such as for a banquet or in the lunch break at factory canteens. To give an even workload, and as far as possible to avoid antisocial hours of work, it is common to spread the preparation of such food over the whole of the working day or over
several days by employing time -shift systems. Time -shift catering techniques are bound to increase greatly the delay between cooking and eating. This makes it essential to cool the food rapidly and to store it safely at chill temperatures (0 -3 °C) or deep frozen ( -18 °C or below) and to reheat it rapidly and thoroughly before consumption. For this to be done safely, properly designed and equipped "cook- chill" or "cook - freeze" systems must be used (see Chapter 3). This requires that the appropriate technology is made available and correctly employed by workers who are well trained and who fully understand what they are doing and the hazards involved. If it is not possible to provide suitably trained workers who can use, monitor and maintain technologically advanced catering equipment properly, then it is safer not to dabble in highly sophisticated catering systems. Instead, simpler systems should be devised which do not require such technology and which are within the capabilities of the available workforce.
Since chilling and freezing have different effects on the quality of different foods, it is often convenient to use a mixture of frozen, chilled and fresh foods, even for just one meal. The catering system will then have to be designed or adapted to cope with the range of techniques required. This may make the work more interesting for the kitchen staff, but it also requires them to have a thorough understanding of the techniques involved.
Other recently developed items of cooking equipment, such as slow cookers and microwave ovens, can present problems if not properly used. The vacuum packing and inert gas packing of prepared foods will
reduce the growth of spoilage organisms but may not affect the growth of pathogens. These methods are all discussed more fully in Chapter 3.
Not only do the kitchen staff need to be properly trained, but so also do the staff who finally serve the food. The food may be reheated, dished up, portioned, served and consumed at a point very remote in both space and time from the point of production. The manager of the central kitchen may not be able to exercise any form of direct control over the staff at remote serving areas. It is therefore necessary that the food be prepared and distributed in such a way that it can be served with the minimum of interference by the servers, thus reducing to a minimum the amount of training and supervision that they need and the harm that they can do by mishandling the food. Alternatively, the government health authority, or the commercial or public institution responsible for the site or premises where the food is to be served, must take suitable steps to ensure that the serving staff are properly trained, equipped and supervised.
The temperature control
of food
is just as important during distribution as during storage. Refrigerated vehicles or containers may be necessary if it is to be carried any distance. The experience in Sweden is that during a journey of not more than 11 hours, the temperature of chilled food in unrefrigerated containers does not rise by more than 2 °C.Sweden is a country with a generally cool climate; the temperature rise of unrefrigerated food will be much greater in hot countries. In any country, if food is not to be eaten within an hour or two of reaching a distant serving point, facilities for refrigerated storage must be provided at that point. All refrigerated vehicles, stores, cabinets, etc. should be fitted with direct -reading thermometers, and preferably also with recording thermometers. These usually measure only the air temperature in the container or chamber, so supervisory staff and other workers responsible for storing or receiving chilled or frozen food should be equipped with hand thermometers to check the temperature of the food itself. Direct -reading electronic thermometers are by far the most suitable for this purpose. Even these must be properly maintained and regularly checked. Staff need to be trained in their use and encouraged to use them on all occasions.
Workforce
Workers in the food industry tend to come from the lower socioeconomic levels. Because of limited education they may have communication problems, read poorly or not at all, and find it difficult to grasp the more advanced technological concepts. Formal training is often not available in the traditional food industry, and even when training is given these people often do not find it easy to take advantage of it, which means that they are unlikely to rise above menial
10
occupations. This reduces job satisfaction and these workers tend to change their employment frequently, throwing an even greater load on the training facilities. Even without a rapid turnover in employees it is hard to explain the relationship between cleanliness and health to new workers from an inadequate socioeconomic and educational back- ground.
These problems may be even greater in developing countries, where understanding of and expectations for health, general sanitation and food hygiene and safety are likely to be low even in the better educated sections of the population. In an investigation carried out in an eastern Mediterranean country faecal organisms, including a wide selection of intestinal pathogens, were found on the hands of over half the people examined, most of whom were from the professional classes. Similar investigations in north -western Europe have not given such results and have demonstrated that faecal organisms can be removed from the skin by thorough washing with soap and warm water. The disturbing findings in the eastern Mediterranean country suggest that toilet practices and hygiene are unsatisfactory throughout the population, possibly for cultural or religious reasons that are common to all classes.
Nutrition
Mass catering provides a means of ensuring a minimum nutritional intake for several sections
of the
population, especially children, although this depends on how much of the meal provided is actuallyeaten. In Finland it was found that only about one quarter of the
nutritionally important foods provided in school meals were actually consumed whereas it had previously been thought that these meals were providing one third of the childrens' total nutritional requirements. A recent study in a Swedish general hospital showed that 7 % of patients did not eat the meat served at lunch and 1 % did not eat the meat served at dinner, while 15 % did not eat the vegetables served at either meal.Failure to eat all the food provided is obviously more important in countries where nutrition is barely adequate. The introduction of mass catering may cause serious problems to a population with little or no previous experience of mass -produced food, since it may create significant alterations in traditional dietary habits.
Epidemiological and nutritional studies may show that it is desirable to make changes in traditional diets, such as by reducing the fat content.
Even with modern technology, however, it may be difficult to reproduce the flavour and texture that makes fried food so popular. It must also be remembered that dietary requirements may vary with climate as well as with age, occupation and so on. Some methods of cooking and storing, including traditional methods, may affect the nutritional content of
food;
there may for
instance be significant lossesof vitamin C.
Whenever new catering systems are introduced, samples of food should be tested for their nutrient content, particularly those likely to be
EVEN (3ASIC HVÇIENE LAU- MAKE ALL 'THE DIFFERENCE
12
affected by the processes, and other sources of the nutrient should be added to the diet if necessary.
While much of the economic advantage of mass catering is to be found in the repeated large -scale buying of a limited range of foods, and in bulk cooking, some flexibility is necessary to allow the provision of a small number of individual meals for those who require special diets for medical or other reasons. This is especially important when catering for groups that cannot easily obtain meals elsewhere, such as children in boarding schools and hospital patients. There is one overriding rule in mass catering: if you cannot ensure the safety of the system that you have chosen, and monitor all its aspects, either do not do it at all or choose a system that is within your capabilities. Time -shift catering, in particular, requires sophisticated technology, intensive monitoring and considerable capital outlay. If these are not all available then simpler systems, with little delay between food preparation and service, will be safer and more satisfactory, though much more labour intensive.
Bibliography
Longree, K. Quantity food sanitation. New York, Wiley Interscience,
1980.
Hobbs, B. C. & Gilbert, R. J. Food poisoning and food hygiene, 4th ed.
London, Edward Arnold, 1978.
Treneva, M. & Demireva, M. [Mass catering, outlook, management and efficiency]. Sofia, Tehnika State Publishing House, 1981.
Bachman, M. R. Technology appropriate to food preservation in developing countries. In: Thorne, S., ed. Developments in food preservation. Barking, Applied Science Publishers, 1981, Vol. 1, pp.
1 -37.
Blaxter, K. & Fowden, L. Food, nutrition and climate. Barking, Applied Science Publishers, 1982.
Management ofgroup feeding programmes. Rome, FAO, 1982 (Food and Nutrition Paper, No. 23).
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2
General methods
of control
Planning and licensing
It is an advantage if some form of licensing can be applied to premises engaged in mass catering
to ensure at
leasta basic standard of
equipment, construction and layout. It is usually not possible to establish more than very general rules about the legal standards that must be achieved before a licence is granted. The detailed requirements for buildings, equipment, etc. will have to vary widely according to the type of food expected to be produced, the size and nature of the population to be served, the local building materials available, the restrictions imposed by the site, and the availability of power, sanitary facilities and raw materials. The licensing inspector must consider first and foremost the implications for the health of the consumer, the worker and people living near the intended premises.Where licences for the setting up of mass catering premises are issued by a central government department, all such licences should also be approved by the ministry responsible for health. It may be useful for central government health departments to send special teams of experts to assist in setting up mass catering projects and to reinforce the local health authorities in dealing with special problems, such as major outbreaks of food poisoning. Central assistance may also be needed at special times, such as at the start of the tourist season when all mass catering premises in tourist areas may need to be inspected.
When considering the introduction of highly sophisticated technology to a new or existing mass catering industry, attention should be paid to cost - benefit and practicability. An assessment should be made of the local availability of suitably skilled labour. Is
it worth the cost of
training local people from scratch? Are spare parts easily obtained or will they have to be bought from abroad, using up foreign exchange and causing delays? Will the benefits of the system outweigh the cost of providing sufficient power, water and waste disposal facilities? Often a simpler scheme may be quite adequate to provide all the meals that are needed and will give more local employment, especially to people lacking advanced technical skills.Countries or organizations without previous experience of mass catering would be well advised to seek the advice of experts in this field, when drawing up or approving plans for the design, construction and equipment of individual premises. Help can be obtained through the World Health Organization (WHO), through governments of countries with experience of mass catering, or from commercial enterprises manufacturing or selling mass catering equipment. Whenever possible, inexperienced managers and inspectors should visit mass catering establishments of the type they wish to install, in order to familiarize themselves with the technology involved and with its problems and special requirements.
When choosing sites for mass catering premises care should be taken that they are well away from pens and lairages for live animals, rubbish tips, etc. which can encourage vermin and may be sources of pathogenic microorganisms. The premises should be protected from flooding and from seepage of possibly contaminated water in low -lying marshy sites.
If mass catering premises are to be set up in industrial areas, thought should be given to protecting them from industrial pollution.
Management and inspection
Any form of mass catering should use modern managerial techniques such as systems analysis, the evaluation of procedures and the auditing of results. This should be done as much for hygiene and safety reasons as for the sake of production and profits. It is essential at all stages that managers understand the health aspects of the processes for which they are responsible.
There should be a free exchange of information between those responsible for production and those responsible for safety. Ideally, each establishment should have a hygiene and quality control officer with status equal to that of the production manager. The official health control agency then has the responsibility only of ensuring that the establishment's own quality control is satisfactory, and of giving advice if necessary. The day -to -day running of the establishment can be left to its own quality control and production managers. This may not be possible when mass catering systems are first introduced to some developing countries where there is no experience of managing such systems. In such cases the official agency must exercise more continuous and detailed health control. Health agencies nonetheless should not become involved in supply and production problems unrelated to health, though other government agencies may need to do so. Health control needs to rest ultimately with an agency that has no responsibility for trade or economic matters. Such control should be exerted as far as possible by advice and education, but there must also be legal powers to ensure safety if premises or procedures are so unsatisfactory that there is
a danger to health.
Legislation may need to be stricter and more detailed when mass catering is being introduced to a population that has no previous experience of such techniques.16
It may provide an incentive to good hygiene if a certificate of satisfactory hygiene is provided for establishments that have passed regular inspection. This certificate could be displayed for customers to
see.
It may also be of value to have a legal requirement that managers must be able to produce evidence of a basic knowledge of hygiene and food technology, such as by having attended an approved course or having passed a recognized examination. Both official inspectors and commercial managers should be kept informed of new food technology and newly recognized hazards.
This may need an exchange
of information and experience among countries as well as among different commercial enterprises. This may conflict with commercial and possibly with national interests and it is therefore best effected through international meetings, expert advisers, publications and other activities of non -commercial and non -political international bodies such as WHO, the Food and Agriculture Organization of the United Nations (FAO), and the Codex Alimentarius Commission.General hygiene
Some foods should be handled only where adequate technology exists to ensure that they can be processed safely. The mass production of elaborate made -up meat dishes requires careful temperature control in cooking, cooling, storage and distribution, and should not be attempted
if the facilities for all this are not available. Provided limitations of this nature are properly appreciated, sensible organization, intelligent management and adequate process control and monitoring can accomplish a great deal, even in the absence of highly sophisticated equipment. The aim should be to achieve a steady flow of work, making full use of the equipment available, but without overloading or creating hold -ups at any point.
All equipment and utensils must be easy to clean, without any damaged areas, crevices, cracks or small apertures that cannot be properly cleaned. Otherwise food, debris and dirt will accumulate and microorganisms, including pathogens, will grow if they are introduced from raw food, from the environment or on workers' hands or clothing.
It is equally important that walls, floors, ceilings and other structures are clean, free from cracks and in good repair. Drains should be kept clean and clear of rubbish, and covered with grills to keep out vermin.
For the same reason windows and doors should be screened.
When a large bulk of food
is cooked, cooled or stored, it isimportant to be able to measure the temperature at its centre; it should not be assumed that this is the same as the temperature of the air in the oven or in the chiller or refrigerator.
Raw and cooked food should be stored and handled completely separately to prevent any direct or indirect transfer of microorganisms from the raw to the cooked food. Wooden working surfaces, chopping
blocks, knife handles, etc. can never be cleaned satisfactorily and should be replaced by steel or synthetic materials.
When food is cooked rapidly and served immediately after cooking, it is often possible to get away with a less than adequate standard of hygiene because there is no time for pathogens to grow in the food.
Sooner or later, however, this is likely to lead to disaster, especially if on occasions there are delays before the food is eaten. Therefore, bad hygiene should never be allowed to persist in any catering establishment, and only the highest standards can be permitted when time -shift catering is being performed.
Staff should be employed at work consistent with their level of training; they should understand what they need to do and why. If employees do not understand the reasons for their instructions they will not be motivated to follow them strictly, and hygiene is likely to suffer.
At all times
it is essential that managers set a good example by observing the same hygienic rules as the employees, especially concerning washing hands, wearing protective clothing, and refraining from eating and smoking in areas where food is handled. This applies with equal force to official inspectors, and to distinguished visitors to food premises.The use of temporary employees should be avoided as
far as
possible. They certainly should not be used in highly vulnerable areas of work such as the handling and chilling of cooked food. It is common to employ such casual, frequently unskilled, and lowly paid workers for washing the equipment and utensils.
If they must be used for this
purpose, intensive supervision is necessary. Washing up must be done thoroughly and correctly to ensure that all items are free from contamination. A properly controlled disinfecting rinse with chemical disinfectant or hot (at least 80 °C) water is always essential at the final stage of cleaning, and care should be taken that subsequent contamination is avoided. Automatic mechanical dish and equipment washers are often more reliable than manual washing up, but have high capital and running costs. The running costs can be somewhat reduced by installing heat recovery systems.Raw material
It is important to ensure that there are sufficient supplies of good quality raw material. There should be adequate space to store it under good conditions, properly protected from pests and the environment. As far as possible, raw materials should be supplied frequently and regularly, and excessive quantities should not be stored. There should nonetheless be sufficient reserves to meet any unexpected increase in demand, rather than having to make ad hoc purchases from local small - scale producers of materials of uncertain quality. Commercial specifi- cations must be devised as part of the contracts with suppliers. To increase the value of these specifications in ensuring and controlling the quality of raw material, it is desirable to have long -term contracts with
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reliable suppliers who have been shown to have adequate and consistent quality control.
Laboratory tests
Each mass catering establishment should have access to facilities for the chemical and microbiological analysis of raw materials, finished products and in- process samples. Care must be taken that pathogenic microorgan- isms isolated in
the laboratory of a food establishment are not
inadvertently carried back to the food -handling areas. If the establish- ment does not have its own laboratory, use can often be made of a reliable commercial or government laboratory. However much testing is done by the establishment's own quality and hygiene control staff (autocontrol), the official health control agency will wish to check this from time to time by sending samples to an official laboratory. The bacteriological methods used in clinical bacteriology are not necessarily the same as those required for the examinationof food.
The conventional medical or veterinary microbiologist may need further training in food microbiology. A number of WHO- approved courses are available, at the Institut Pasteur in Lille, at the University of Surrey, at Zeist in the Netherlands, and through the FAO /WHO Collaborating Centre for Training and Research in Food Hygiene and Zoonoses, Berlin (West).Even if a mass catering establishment does not possess its own laboratory, quality control production
be able to perform a few simple chemical and microbiological screening tests for general hygiene, compositional quality, and the presence of common contaminants.
When considering any test it is necessary to look at its weaknesses as well as its advantages. All tests have their inherent errors and lack of sensitivity, microbiological more so than chemical tests. The agent that the test is intended to detect may not be distributed evenly through the consignment being sampled; again, this is more likely to occur with microbial than chemical contamination. It is often not economically feasible to take and test sufficient samples to get a result sufficiently representative of the entire batch. Indeed, particularly with some forms of microbial contamination, one could test and find satisfactory all but one item out of a batch of several million and still not be absolutely certain that the last item was not contaminated. Testing therefore cannot take the place of proper supervision of the hygiene of all aspects of preparation, storage and distribution. Laboratory testing is a useful aid in providing further checks on that process control, but on its own it can never ensure safety.
Laboratory resources and trained staff are expensive and in short supply in all countries especially, of course, in the developing countries.
Laboratory tests should therefore be used only when they will be effective and where no other less expensive method of control can be used.
Ingredients should be of reasonable microbiological quality, but they need not necessarily be free from pathogens if they are to be cooked or treated in such a way as to kill microorganisms or render them non - infective. Simple bacteriological tests, such as total mesophilic colony
counts and coliform counts, may be of value in giving a general
indication of the cleanliness and freshness of raw ingredients. Often,however, these counts do not correlate well with the presence or
absence of pathogens and it isnot wise to use them as absolute
indicators of the microbiological safety of raw foods. Furthermore,much if not all of the food is
likely to have been processed and consumed before the results of the test are known. Such tests can be used to provide a retrospective assessment of the level and consistency of the quality of the raw material provided by different producers, thus assisting the catering manager to check that his quality and hygiene standards have been met by the supplier. As he gains experience this will enable him to buy only from suppliers who can maintain adequate standards. Chemical testing can be done rather more quickly; again, it is probably not practicable to test all consignments. It is far moreimportant that some form of assurance be obtained that the raw
materials have not been exposed to undesirable contaminants, or that pesticidesor growth promoters have not been used
in excessivequantities or used within a certain period before slaughter or harvesting.
Producers or official agencies may be able to provide certificates to this effect, or official certificates may be given after appropriate testing. The results of even these official tests may be affected by sampling errors or laboratory variations. If official tests are not performed the catering manager may well wish to do occasional spot checks for additives and contaminants that are a local problem, in order to verify the reliability of his suppliers.
Routine microbiological testing of the end -product is probably never cost -effective. Nonetheless, samples may be taken for testing from critical points in the production process. Simple tests such as total counts and coliform counts are generally most useful for this purpose.
They are inexpensive and can be repeated frequently, and the results are available relatively quickly. The catering manager will probably need to establish his own normal limits based on intensive testing. This testing should be carried out when any mass catering establishment first goes into operation, and different numerical limits may be needed for different types of food. If there is any significant change in equipment or techniques of production or in types of food, then these tests will need to be repeated. Once the norms are established, any deviation from them should be used as an indication that something has gone wrong and should lead to intensive investigation as to the cause.
It may not
necessarily indicate that the food is unsafe, but it must lead to further checking. In addition to testing the food at appropriate points along the production line, it may also be necessary to swab working surfaces and equipment to detect any build -up of organisms. The efficacy of cleaning and disinfecting procedures should also be checked in this way. It needs 20to be remembered that normal values for food are significant only for the point in the production line where they have been established. It is extremely unwise to assume that a normal value derived from tests on food sampled immediately after cooking and just before chill or frozen storage, will be equally applicable to the food at the end of the storage period, during distribution or after reheating.
Convenient and repeated microbiological testing can be done with dip slides. These are plastic slides covered with a choice of general or selective growth media. They can be dipped into fluid or pressed against solids. They were originally devised for testing urine, but it has been shown that they can be applied to the sampling of a wide range of liquids or solid surfaces. After inoculation the slide is replaced in its sterile container and incubated for a specified time. Visible colonies are then counted. These slides
are made by
a commercial medium manufacturer and, though relatively expensive, can be used by people with little training in microbiology. The catering staff can easily be shown how to use them to establish normal limits for different parts of the kitchen or serving areas. They can then identify points where a build -up of organisms may occur, recognize when such a build -up is occurring, and assess the relative effectiveness of different cleaning and disinfecting regimes. This test is also extremely useful in demonstrating to staff that microbiological problems exist, how they occur and how they can be avoided.When an establishment or process first goes into operation, it may be of value to look for pathogens relevant to the raw material or to the procedure. For example, it may be useful to look for the survival of salmonellae in cooked food of animal origin, or for Staphylococcus aureus or Clostridium perfringens in food that is extensively manipulated, in order to assist in determining that the procedures used will produce safe food. This needs to be done as a pilot investigation before the establishment goes into full commercial operation. Under normal commercial conditions the food will have been distributed and eaten before the results are obtained.
Chemical testing of the end -product for undesirable additives and contaminants is probably unnecessary if there is adequate control of the raw materials or assurance that the raw materials are free from chemical contamination, and if there is no reason to suspect that undesirable additives or contaminants have entered the food during processing. It is important to be sure that not only the main raw materials but also spices, salts, and processing adjuvants are all of a chemical purity satisfactory for human consumption. The level of purity normally required for some industrial chemicals, sodium chloride for example, may not be adequate for their use in foods.
HACCP
A procedure that is being extensively adopted in the United States of America involves the concept of a "hazard analysis critical control
point" (HACCP). A food or group of foods is identified as hazardous
on the basis of the technical details of the process or subsequent
handling, or evidence of illness or spoilage. A detailed and systematic investigation of the entire procedure of production, distribution and use of the food is then carried out. The results of this investigation are analysed to identify how and where these hazards arise, at which pointscontrols should be established, and what control and monitoring
procedures should be applied at these points. These pro- cedures may consist of the microbiological testing of samples of the food taken at each critical point, or other tests that may be more appropriate, such as time and temperature monitoring or pH measurement. None of this is particularly new, but what is important is the greatly increased emphasis on systematic analysis of the hazard and on identifying the critical points, and the concentration of resources on the most appropriate means of control at those points. At some critical points, of course, complete control by objective test may not be possible. Then, the detection and prevention of cross contamination may rely more on the supervision and proper training of workers than on a microbiological test.
Use of this method seems likely to be considerably more cost - effective than intensive end -product testing, which it will largely or entirely replace. Essential concomitants of the HACCP procedure are the retention of all process records and results of monitoring, a means of identifying all batches of the food, and a system for preventing the
use or distribution of hazardous food. While this procedure was
developed to deal with microbial contamination, a similar approach can be devised for chemical contamination.Water
It is imperative that the mains water supply be of the highest standard for drinking water recommended by the World Health Organization.°
All water entering the premises for use in food preparation, including the washing of utensils and equipment, must be of this standard, that is that no coliforms should be detectable in 100 ml. If supplies of water of lower quality enter the premises, for fire -fighting or cooling for example, care must be taken that there is no connection with the drinking water supply. Non -drinking water must not even be used for washing the floors in food handling areas. If there is any leak from the non -drinking water system that might contaminate food such food must be rejected, or at least washed to remove any chemical contamination and given a bactericidal cook. The official agency responsible for health must be consulted before attempting to salvage any such food. If the quality of the water is likely to deteriorate after entering the premises, by storage in a tank for example, samples taken at a number of outlets should be
a International standards for drinking water, 3rd ed. Geneva, WHO, 1971.
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regularly tested. Coliform tests should be performed at least monthly.
The water should at all times meet the criteria of the WHO drinking water guidelines, and if it is to come into contact with food that will not receive a thorough cook before consumption, no coliforms should be detectable in any 100 -ml sample. A weekly total colony count should also be performed after three days' incubation at 22 °C. From the results of repeated tests, a normal value for the total colony count should be found for each catering establishment; any deviation from this should be intensively investigated to discover the cause and its significance for health. As a general rule, the limits should be below 100 colonies in 1 ml. This testing may be done by the official health agency or by the establishment's own quality control laboratory, but it is the responsi- bility of the official agency to satisfy itself of the reliability of the establishment's own control, by checking results and sending samples to an official laboratory as necessary. Before the catering establishment goes into operation, sufficient samples of water should have been analysed to show that the water in the mains supply and the distribution system is consistently of a satisfactory quality. If there are any doubts about the water reaching the premises or distributed in the premises, it should be treated appropriately. Microbial contamination is the most
likely hazard, and if there is any fear of this the water should be
chlorinated or otherwise disinfected on the premises. If chlorine gas or hypochlorite is used, sufficient should be added to give a residual free chlorine concentration of at least 0.2 mg /litre in water entering the distribution system. This should be measured at least twice a day.Disinfection of the water does not remove the need for
regularmicrobiological testing.
Personal hygiene
The routine clinical and microbiological examination of food handlers is not recommended as a means of preventing the contamination of food with the organisms that cause food poisoning and other foodborne diseases. It is very expensive in medical and laboratory resources and can never guarantee that all carriers of intestinal diseases are excluded from food handling. Anyway, carriers among food handlers are responsible for only a very small proportion of outbreaks of foodborne disease; disease is usually due to contamination from the raw food ingredients or from the environment by way of dust, polluted water, pests, etc. Risks from carriers can be eliminated if proper hygiene is always observed, especially by thorough washing of the hands after visiting the toilet, and if at all times the food is handled and processed in such a way that no pathogenic organisms or their toxins can survive in an active harmful form in the finished food. Whilst routine medical and laboratory examination of food handlers is not recommended, it is important that anyone with an obvious infection of the skin, nose, ear or throat, or any gastrointestinal upset, should not be allowed to work where he could contaminate food, without the consent of the medical
authorities. It is a good idea for the manager or supervisor to inspect the workers daily for signs of infection of exposed areas of skin. This also affords the opportunity to remind them to report any gastro- intestinal symptoms in themselves or their immediate families. Workers with diarrhoea should never be allowed to handle open food, even if no pathogens can be isolated from their stools; many organisms, especially enteroviruses, cannot be detected on routine culture.
Even if they have already washed their hands in the toilet or
changing room, all people (workers, managers, inspectors, etc.) should wash their hands thoroughly with soap and warm water immediately on entering the food handling area. Workers handling raw food should wash their hands before touching cooked food or entering an area where cooked food is handled.The hand -washing basins must be quite separate from the sinks used for washing food or equipment and utensils. There should be a good supply of suitable soap and warm water, or hot and cold water.
Preferably the taps should be of the type that do not have to be touched by the hand. If towels are used for drying the hands, they should be the kind that are used only once.
Kitchen staff should not be allowed to bring any food into the food handling areas, or to smoke, eat or drink there, since this may spread contamination from their mouths and noses to the food that is being processed. They should have all their meals in the main canteen or in a staff dining -room quite separate from the kitchen.
Epidemiology
While the actual organisms associated with foodborne disease may differ somewhat from country to country, the basic principles of food hygiene remain the same. It is not necessary for a great deal of time and money to be spent on obsessively detailed research into prime causes when enough is already known (as it usually is) about the immediate cause to enable preventive measures to be taken to reduce the risk of illness significantly, even if not to eradicate it totally. There is no need for every country that wishes to develop a mass catering industry to hunt for every organism that might be present in the national food supply, and then to perform even more prolonged research to establish if these organisms are in fact pathogens. The experience of countries with long-
established food industries and programmes for monitoring the effect of food on the public health indicates clearly that it is best to assume that all raw food contains pathogenic organisms. It is equally clear that these can be killdd, removed or reduced to concentrations that are harmless by appropriate treatment of the food. This includes cooking or washing, with or without a mild disinfectant, then preventing recontamination as far as possible, especially from raw food, and keeping the food at temperatures that will not permit the growth of pathogens. These measures are valid for all foods in all countries.
A great deal of information is already available about the effect of
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