A well-planned, well-executed and controlled cleaning and sanitation programme for rooms, machines and equipment is very important to achieve a hygienic standard. Cleaning and sanitation alone, however, will not assure a hygienic standard in production where process hygiene as well as personal hygiene are important factors.
Well-planned working routines may assure a better cleaning standard during processing. For example, cleaning during processing, removal of solid waste and sufficient space in processing rooms are factors which facilitate cleaning.
Adequate personal hygiene assures the overall cleaning process. Deterioration of the cleaning standard may occur if microorganisms are transmitted to well-cleaned surfaces from unwashed hands before processing starts.
Neither process hygiene, personal hygiene nor cleaning and sanitation alone can assure a sufficient hygienic standard but together, if carried out in an optimal manner, they will guarantee a complete hygienic standard.
It is impossible to give an adequate definition of process hygiene because the critical points will vary, depending on:
processing buildings (site, size, buildings)
permanent or non-permanent personnel (working routines, training)
water and energy supplies
liquid and solid waste disposal
The slaughterhouse should be situated away from residential areas. Access for animals - either by road, rail and/or stock route - must be assured. The slaughterhouse should be located in areas where flooding is impossible.
An abundant supply of potable water as well as adequate facilities for treatment and disposal is important.
The land acquired for the proposed slaughterhouse should be sufficient to permit future expansion as overcrowding of facilities may give sanitation problems.
Where the “slaughterhouse” is more or less an open slaughterplace, trees may provide some shade or even be used as a part of the structure. If the slaughterhouse consists of regular buildings the ground should be free of shubbery or vegetation in close proximity to the structure.
There should be a reasonable relationship between the size of slaughter facilities and the number of animals to be killed.
Sufficient space for lairage and tripe and hide treatment is required. The space required for lairage will often depend on local and even climatic conditions. In specific areas it will only be possible to transport the animals in the dry season while slaughtering may only be carried out in the rainy season because of water requirements.
Sufficient space is required to dig pits for condemned animals, compost stacks, lavatories etc., and for disposal of liquid and solid waste.
Buildings / facilities should be so constructed that clean and unclean processes and products do not mix.
The floor must be hard, smooth and impervious, sloping sufficiently towards a drain thus allowing cleaning with water.
Walls, if any, may be made of local construction materials. In certain dry areas walls are not necessary. Materials, which can be cleaned by water, are recommended, e.g. stone, lava blocks, bricks or concrete.
Roofs, if any, may be constructed of materials available (tiles, corrugated iron, asbestos or aluminium).
Roofing is recommended:
to protect and allow the slaughter process to be independent of the weather
to provide shade and keep down the internal temperature
to enable the collection of rainwater in water tanks.
For detailed planning and construction of slaughterhouses/ slaughter facilities reference is made to “Slaughterhouse and slaughterslab design and construction”, FAO Animal Production and Health Paper no. 9, by P.J. Eriksen, FAO, Rome, 1978 and “Guidelines on small slaughterhouses and meat hygiene for developing countries”, VPH/85.56 by I. Mann, WHO, Geneva, 1984.
The main principle for equipment such as tables, hooks and machines, etc. should be that it is easy to dismantle or remove to facilitate cleaning and that it should be made of non-corrosive materials.
Essential for the hygienic handling of carcasses and meat is equipment for hoisting the carcasses, when slaughtered. Hoists, when possible, should be preferred to working tables. Procedures assuring a periodical or continuous cleaning of hoists are recommended.
Cleaning and disinfection will often be complicated or impossible because of the complex construction of machines and when choosing and buying machines, hygienic production and possibilities for cleaning and disinfection must be considered.
Many large slaughterhouses have permanent personnel performing all work in the slaughterhouses. Organization will depend on the type of production. Where personnel is permanent, a few lessons regarding process hygiene, personal hygiene, and cleaning and disinfection may be given.
Ideally, personnel should be organized in a way that part of the staff is occupied with cleaning and disinfection. This group of personnel must be educated and trained especially in cleaning and disinfection procedures as well as general hygiene.
Where the slaughterhouse/slaughter facilities cover the need for slaughtering in big areas in developing countries, the slaughterhouse is often owned by municipalities and organized with a manager and no permanent staff. Slaughtering is done by local butchers and a team employed by these butchers and thus it will be difficult to give them sufficient education and training in hygiene.
It is therefore recommended that the manager of the slaughterhouse/slaughter facilities employ a team which is responsible for maintenance of a hygienic standard. This team should do some clearing and cleaning during slaughtering hours or instruct the butchers and workers to do this during and after slaughtering. This team will be responsible for cleaning and disinfection at the end of the working day and in maintaining the hygienic standard.
Climatic conditions will influence hygiene and processing. Different precautions should be taken depending on the climate in the area as they are not the same in a temperate as in a tropical climate.
Requirements regarding buildings, (see 2.1) processing (see 2.7) and working vary according to climatic conditions.
In a tropical climate it will often be necessary to start slaughtering during the night hours before sunrise and distribute the meat for sale in the morning hours. Slaughterhouses/slaughter facilities in these areas may be very weather-dependent (outdoor temperature, rainy/ dry periods, water supplies etc.). The floor and wall surfaces etc. in this kind of slaughterhouses will in dry periods be allowed to dry completely thus assuring that no microorganisms will multiply. If water supplies are insufficient, e.g. in dry periods, surfaces should be scraped clean and then sun-dried if possible. This procedure will presumably give the same or even better hygienic results than a cleaning process with insufficient amounts of water.
In large, commercial slaughterhouses in tropical climates the working routines will be the same as those in large slaughterhouses in temperate climates. For this type of slaughterhouses, work will be almost independent of weather conditions.
Water points, hoses, sterilizers for hand tools etc. and cleaning equipment must be provided in sufficient numbers. Where possible sterilizers should be supplied with hot water instead of chemical disinfectants.
Sanitary facilities must also include a sufficient number of toilets/latrines and arrangements for hand-washing or even possibilities for bathing (showering). These facilities must be kept clean and well maintained.
To avoid back-flow from toilets in case of flooding the toilet outlets must be separated from common waste water outlets.
Areas/rooms for resting and eating may be required assuring that food for the personnel and the carcasses/meat cannot be mixed.
If sufficient water of drinking quality is available, it will be possible to plan processing and cleaning procedures in a way which assures hygienic products. The water supply may be from the premises own well or from the community supply. Working routines should be planned to economize the consumption of water because of waste water disposal.
Energy supplies will be necessary if the slaughterhouse is more or less automatic. Energy supplies will also be necessary for automatic cleaning and could be provided through windmills, biogas production, fuel and electricity and water could also be heated by solar energy.
If water and energy supplies are sufficient it will be the responsibility of the management of the slaughterhouse to see that these supplies are used efficiently and that sufficient water and energy are used for hygienic purposes.
The elements of hygiene will differ depending on the type of processing. There will be significant differences between the hygiene standard required in a plant manufacturing meat products, which are sold as sliced, prepackaged meat products, and the hygienic standard required in a place where the animals are slaughtered.
The main hygiene principle in processing is that clean and unclean operations are efficiently separated. This requires a wellplanned plant layout, where the purpose of any structure should be to protect the products against unintended contamination.
Processing principles are shown in the following flow-diagram (Fig. 3).
Fig. 3. Flow-diagram showing the principles in a slaughtering process. The subprocesses are divided in “dirty” and “clean” operations.
Hanging/chilling, cutting/deboning, and/or freezing depend on local conditions.
Lairage: there should be sufficient space and a sufficient supply of potable water for drinking purposes. A spraying system where the animals can be cleaned before entering the slaughterhouse is recommended, if sufficient water is available. The floor should be constructed of concrete and sloping towards drains in order to facilitate cleaning.
Regulations concerning feeding and watering of the animals before slaughter should be considered.
These processes must, if possible, be separated from the operations which follow. If the blood is not intended for use it should be drained away into a separate pit and should not be allowed to drain into the waste water. The animals should be hoisted to facilitate bleeding and decrease the risk of contamination of the carcasses.
This area should be constructed with a slope towards drains (ref. FAO 1978).
The process varies according to animal (poultry, pigs and cattle).
Skinning or dehairing may be carried out in a separate room/area or in the slaughtering place. However, it should be carried out separately from the evisceration process. The same principle applies to plucking of poultry.
The unskinned/undehaired carcass must never enter the clean area, but as soon as possible after skinning, dehairing, or plucking, it must be hygienically transferred to the clean area (evisceration room/or area). It is important to handle the carcass carefully to minimize contamination.
To secure and improve cleanliness and efficiency hoists and overhead rails are required for the skinning/dehairing process. If hoists and overhead rails are not available, the carcasses should be kept above floor level by means of cradles. Procedures assuring cleaning of hoists, overhead rails and cradles should be established.
Special rooms/areas should be available for treatment of hides.
During the evisceration process care should be taken to minimize contamination. Special care must be taken to avoid damaging the intestines. Edible organs must be handled in a hygienic way (stored/ removed in separate containers etc.). Waste must be removed rapidly from the floor in the evisceration room/area.
A sufficient number of sterilizers for hand tools, knives, etc. must also be available in the evisceration area.
Carcasses may be chilled or divided in halves or quarters and then distributed for sale as soon as possible. When chilling is carried out, there must be sufficient chilling capacity and space to assure sufficient chilling.
Carcasses can even be chilled when they are just hanging up and are air-dried, chilling being caused by evaporation.
If cutting and/or deboning is carried out care must be taken to minimize contamination of the meat. The carcasses must be cut, preferably hanging or on surfaces (tables, cutting planks, chopping blocks), which are regularly cleaned. A sufficient amount of sterilizers must be available for cleaning of hand tools, knives, etc. The meat must be removed and/or stored in clean containers, which solely are used for meat. Disposable containers will assure hygienic transport and storage, but will be costly.
The meat may be packaged ready for the retail trade. If this is done, the packaging must be done in a way to prevent contamination of the meat. The packaging material must be clean and approved for food.
If the meat is frozen the freezing capacity must be sufficient to assure correct freezing.
A separate lockable room or area for keeping condemned material until the end of the working day should be provided. An incinerator or a deep pit should be available for disposal of condemned material.
The easiest disposal method is to divert effluents into existing pools, rivers or lakes. However, this method cannot be recommended in view of the consequent contamination of water sources for humans, and domestic and wild animals.
For the safe disposal of liquid and solid waste, the following action should be taken:
Separation of blood
Screening of solids
Trapping of grease
The blood from slaughtered animals will coagulate into a solid mass, which may block up both open and closed drains. It is therefore recommended that the blood is collected and used for human consumption, stockfeed production or fertilizers, if the religious and cultural traditions allow the use of blood.
Solids (meat or skin trimmings, hair, pieces of bones, hooves, etc.) must be screened. This may be done by providing the drains with vertical sieves.
Effluents from slaughterhouses always contain small amounts of fat (melted fat or small pieces of fatty tissues). Grease traps should be installed in the drains. The fat solidifies, rises to the surface and can be removed regularly.
The final effluent disposal will depend on local conditions and legislation. Disposal of the effluents into a lake or permanent river should not be allowed because it will contaminate the stream.
For further details see FAO (1978), Mann (1984), and the Danish Academy of Technical Sciences (1985).
Environmental hygiene and its implementation will depend on the area where the slaughterhouse/meat plant is situated. The precautions to be taken will be different if the site is in a town or in the country.
The main principles of environmental hygiene will consist of:
proper fencing (public, dogs, etc.)
pest control (rodents, insects)
liquid and solid waste disposal
To prevent access of unauthorized persons, the public, dogs and other animals fencing must be erected around the slaughterhouse area. The fencing should have contact with the ground at the lower edge and should be high enough to prevent access to the grounds.
Pests (insect, rodents and birds) should be controlled to prevent their access to slaughterhouses, production areas and storage departments. This is best achieved by the construction of buildings and working places where access of insects, rodents and birds is hindered, but it will be almost impossible to secure buildings totally against pests. However good design and construction may delay the entry of pests which is a worthwhile objective of an overall rodent control programme. Even if the buildings are well-constructed and as pest-proof as possible it will be necessary to have a regular pest control.
Principles in insect control may be:
Biological control through emphasis on the natural enemies of pests.
Cultural control through alteration of the environment to make it unfavourable to pests. Sanitation programmes and water management are examples.
Physical and mechanical control. Burning and sticky adhesives are examples.
Autocidal control, disrupting the breeding cycle of a pest (release of sterilized male insects or genetically altered insects).
Behavioural control, which involves the identification, production, and application of chemical attractants which draw the insects to a trap or interrupt and confuse breeding patterns.
Chemical control, which is the most obvious control method, but also the most controversial of all control methods. This method includes chemical insecticides but non-chemical methods should be employed if possible.
These principles can also be used for the control of rodents and birds but the slower generation time of these animals reduces some of the above-mentioned alternatives.
The most effective way to control rats is to separate them from food supplies forcing the rats to migrate in search of food thus depressing the reproduction rate. This can only be done through careful management of hygiene standards in food production.
Other principles in rodent control are:
The most used method for chemical control of rodents is to prebait which overcomes most problems of shyness and avoidance when baiting. In prebaiting a non-poisoned bait is introduced for a rat population over a period and then the non-poisoned bait is replaced with the identical poisonous variety of bait.
The rodenticides used as baits can be divided into two main types, multiple dose of chronic chemicals, and single-dose (acute) rodenticides. According to the situation, each type can be recommended.
The type of bait station used will depend on its location. It is important to prevent spread of rodenticides in the production areas and the bait stations must be inspected regularly.
Chemical control may include the use of rodenticides as tracking powder. These materials kill rats when the animal grooms itself after having been in touch with the powder. Tracking powders (like other baits) should not be used in production areas.
The best known method of physical control is traps. Trapping is of special importance in an environment where food is produced, handled or stored because poisonous baits cannot be used for safety reasons.
Rodents (rats) have natural enemies such as cats and dogs, but these animals should not be permitted to control (kill) rodents in food production areas.
The best control is to prevent the birds from having access to buildings. It is important to understand the relationship between birds and their environment. Bird attractants may be food supplies, water, special vegetation around buildings, etc. and these attractants must be removed or modified.
Toxicants, shooting and trapping may be used to control birds.
Handling of liquid and solid waste influences both hygiene in processing and of the environment (see 2.7.9), the latter depending on the precautions taken to avoid contamination with liquid and solid waste.
Personal hygiene will usually be the main element in the term “hygiene”; the reason being obvious. Bacteria causing diseases or spoilage may be carried and transmitted to surfaces and food by workers handling the food products.
Careful and frequent hand-washing will do much to reduce contamination. Therefore hand-washing facilities must be sufficient if the water supply is adequate.
Basically there should be two sites where the staff can wash their hands - the rest room and the working area where sufficient handwashing facilities must be placed close to the working places. If the hand-washing facilities are situated in particular areas away from working places, there is a great risk that they will not be used.
It must be impressed on the staff that hand-washing must be done:
before work starts
after using the toilets
after touching dirty objects and materials
after smoking and eating
It must be impressed on the staff that hands will be contaminated if used for scratching the skin or the hair, correcting clothes and picking the nose. Bacteria may be transmitted to the hands by these acts and thereafter transmitted to meat (food) which is handled by hand.
Special guidelines concerning hand-washing must be followed. The management of slaughterhouse/slaughter facilities or the authorities may require the use of a special bacteriostatic soap or dipping of the hands after washing in a germicidal rinse etc. Use of a nail brush is recommended because bacteria often hide along and under the nails.
The clothing of slaughterhouse workers must be clean. The purpose is not to protect the worker against contamination but to protect the meat/food against contamination. Working clothes must be used exclusively in the working area and nowhere else. If possible, it is advisable to avoid admittance from the unclean area to the clean area without changing clothes. Working routines should be planned in a way that the staff works either in the clean area or in the unclean area. The staff may eventually be allowed to go from clean to unclean work but never in the opposite direction, except when they have changed working clothes and washed hands.
Working clothes should be comfortable and easy to wash. Their design should encourage good hygiene habits. Light coloured working clothes show the need for cleaning earlier than dark coloured working clothes.
In tropical climates a loincloth is recommended dispensing with working clothes.
In areas where more clothes than loincloths are necessary, aprons made of washable or even waterproof materials, such as rubber, are recommended.
Working clothes should be free of loose adornments (buttons, sequins etc.). During work jewellery, wrist-watches etc. are prohibited as these objects may be sources for contamination and make hand-washing difficult.
Working clothes should ideally be supplied by the slaughterhouse and a laundry service is recommended to assure a certain level of hygiene.
Arrangements for storage of aprons and tools should be available outside toilets and rest rooms.
Human hair and beards are normally heavily contaminated with bacteria and to prevent contamination of food a hair or beard covering in the process area is a necessary part of the working clothes.
Many different types of hair coverings are seen in the food industry. It is important that the hair is completely covered and that the covering is clean. Disposable or washable hair and beard coverings are recommended.
If the use of gloves is indicated they must be kept in the same good hygienic conditions as hands, otherwise it is better to avoid their use. Gloves may be of rubber or plastic and they are used to protect the meat against contamination. They may also be used to protect the hands against knife cuts and will then be made of steel. Great care should be taken to keep a certain hygienic standard of these gloves.
Good health is important for workers in the meat industry. Ill persons will often be carriers of more microorganisms (pathogenic microorganisms) than is usually the case. These microorganisms may then be transmitted to the meat/food with the risk of causing disease to the consumers. Illness must always be reported to the manager and/or the meat inspector of the slaughterhouse who will decide if the worker can stay or has to leave.
The cleaning programme (see 7) must be performed regularly, dependent on the demand for cleaning in the specific areas. The requirements for cleaning have to be defined before establishing cleaning programmes (see 7.4).
The disinfection programme should follow the cleaning programme and must be planned in relation to the previous cleaning programme and specific requirements.
Sanitation includes more than disinfection, and procedures concerning sanitation (pest control, waste disposal, maintenance of buildings, proper fencing, etc.) should be planned and carried out accordingly.
It must be impressed on everybody employed in the meat/food industry, that hygiene concerns both:
and that regulations in this regard must be observed.