Utility Services

While studying the ideal layout of modern abattoir you must have noticed a utility block.

The utility block comprises of uniform change room for male and female workers, showers, laundry room and dispensary. Actually the section is meant for utilization by people rendering their services to plant. It should be designed and planned properly.

Following facilities should be provided in the utility block:

Entrance: Preferably separate entrance should be designed for male and female workers. The privacy should be ensured.

Lockers: Each and every individual should be provided a separate shelf with key and lock facility where they can keep their valuable purse, rings, clothes etc. Although a locker facility/cloak room is being provided at the main entrance itself, still a small shelf is needed in utility block section. 

Toilet/Urinals: There should be separate toilet/urinals for male and female. The number of toilets/urinals should be sufficient according to strength of workers. Usually 4 to 6 toilets/urinals att sufficient for 100 workers. Care for proper cleaning of toilet/urinals should be taken. There must be an exhaust in each toilet and its direction must be properly guided. There should be separate sewage line connecting to toilet/urinals. Some antiodourous tablets must be kept in urinals. 

Shower: All members working in the factory should take shower and change their clothes. Separate showers for male and female workers and sufficient number must be provided i.e.,one for every 15 employees. 

Dressing room: Adjacent to bath room there should be dressing room where the wet clothing could be put off. Soiled clothing should be separately kept in containers for washing every day. In dressing room there must be a mirror but any type of hard cosmetics should be prohibited. 

Apron, caps, mask and gloves: Every individual should be provided a sterilized apron, cap and mask. Its colour may be different as per working section. All individual should wear cap in such a manner that the chances of hair fall could be minimized. Mask is meant to prevent any contamination from worker's mouth or nose. Gloves are provided to workers of specialized section to prevent contact of meat with bare hand. 

Gumboots/shoes: Gum boots for abattoir workers and shoes for clean area workers should be provided. Foot dip with disinfectants for foot wears at entrance and exit is required.

Wash basin: Wash basins or elongated washing troughs with individual taps must be provided one for every 15 employees. The taps should either be foot or knee operated to prevent contamination. Some soap solution must be provided which should not be possesses a strong odour. 

Canteen: There should be canteen for the staffs preferably separate for workers of clean and semi-clean areas. Alternatively, shift systems should be introduced first for the clean area workers followed by workers from unclean area.  

Dispensary: Facilities for first aid and medical treatment should be available in the abattoir. General check up is required for all workers before their appointment and also periodically once in three/six months. 

Veterinary office: It should be adequately equipped for exclusive use of veterinary services including diagnosis of animal diseases. 

Training hall: A training hall should be there to train employees and meat inspectors for maintaining hygiene and quality control of meat and meat products and sanitation in the abattoir. 

Audio-visual system: It may be introduced for the workers to learn the latest techniques.

Common room: There should be a common room with means of entertainment such as Television, Transistor, indoor games etc. 

Meeting hall: There should be a meeting hall for discussion of activities going on and any type of disputes or complaint etc. 

Utility Services and Plant Management

A modern abattoir/meat plant is not merely a slaughterhouse where animals are killed for meat but it is a food factory where all the operations are dictated by standards of hygiene and animal welfare. Therefore, to produce wholesome meat for the consumers, it is essential to maintain quality parameters related to health, hygiene and sanitation during the entire process. Personal hygiene and cleanliness practices followed by the worker are very important in this regard. Persons with clean hands, clothing and good hygienic practices are absolutely essential to the production of high quality meat. For smooth running of an abattoir number of personnel are placed in different divisions with defined job responsibility which includes production manager, quality control manager, veterinary doctors etc. 

The yield of the by-product (blood, skin, bones etc.) from meat animal is about 45-55 per cent of the live weight and if not utilized properly can lead to economic loss and environmental pollution. Therefore, recovery of by-products and their conversion into value added products such as sausage casings from animal intestine, tallow and lard from animal fat, wool from sheep's skin, hide from cattle, animal scrap, bone (used in poultry and other feeds), blood, gelatin, etc. forms an integral part of the meat plant.

Permission from Concerned Authorities

Practices at abattoir such as bleeding, skin removal, deboning, meat cutting are not very pleasant to see. It needs their operation in an isolated area i.e.,away from residential area The municipality/local bodies take care of such things. During an abattoir practices a number of waste material is also produced and if allowed to accumulate may lead to grave situation of offensive odour and biomass. Proper disposal of waste, problem of sound during abattoir practices have to be taken care. Usually, abattoir is located in the outskirt of town or city. As discussed earlier abattoir practices produces a lot of wastes. Their treatment and disposal is under the governance of State/Central authority. The spread of bone and flesh attract a number of birds and, therefore, an abattoir must be away from airports to prevent bird menace to aircraft's. While establishing an abattoir like other industrial plant, no objection is needed from many of the organization like Municipality/Local bodies, Pollution controls Board, State/central Government. No objection from local airport authority is also required. 

Religious Consideration

Our nation has a diverse out turn. Here people from different communal backgrounds live together. We are having a population of vegetarian who do not favour the slaughter of animal. Not only this, even among non-vegetarian community some opposes the slaughter of pig while others oppose cow. The sentiments of these people are linked to their religion and, therefore, it should not be hurt in any way to keep peaceful communal harmony. It all mean to say an abattoir dealing with pork must not be established in area with population of Muslims and similarly those dealing with beef must not be established in area with Hindus. There are people who do not favour animal slaughter and in this locality no abattoir should be established. 

Direction of the Sun and Prevailing Wind

The sun and prevailing Wind have bearing on the location of site. The site of the abattoir should be such that it does not pollute nearby residential areas. Like all other buildings lighting and ventilation is of primary concern. Direct sunlight is supposed to be a very good natural disinfectant, therefore, their presence particularly in area of effluent treatment must be ensured. 

Site Dimension

Surplus Land for Expansion 

There could be various programme of expansion on lines, of primary, secondary or tertiary processing of meat. You should know that in an abattoir, primary processing pertains to slaughtering of the animal which is converted into carcass while secondary processing refers to the production of commercial cuts including chilling and freezing and tertiary processing means production of ready to eat items such as nuggets, sausages etc. Therefore, it is ideal to have surplus land and for further expansion of the plant as and when required. 

Environment

Freedom from Pollution from Other Industries 

The meat is such a commodity which easily picks up odour of environment and if any such odour prevails as a result of pollution, it affects the quality of meat. The abattoir should be situated away from chemical industries as the pollution caused by chemical industries such as paint, odour, dust, smoke and ash suspects clean and hygienic production of meat. Moreover, the presence of pollutant in environment also affects the livestock in lairage and working manpower. The abattoir should be at sufficient distance from any river to avoid water pollution. 

Distance from Other Buildings 

The abattoir should be at a reasonable distance from local housing and other development to avoid complaints about noise and smell. 

Avoidance of Birds and Insects 

A large amount of solid wastes and by-products is produced from on abattoir. These wastes and by-products attract birds and insect. Therefore, the bushes and trees should be cleaned/cleared around 20 meters of the meat plant for above purpose.

Services

Water Supply 

An adequate supply of potable water must be available. While mains water is to be preferred, well or bore water will also be suitable provided the water meets drinking water standard. Abattoir practices need a lot of water even more than 10,000 liter/ton dressed carcass weight.

Requirement of water for slaughter and dressing of different animal 

The water for drinking/factory use is to be tested from authorized organization. The chemical and microbiological quality of water must be checked carefully. The water is being used for carcass washing, instrument washing, plant washing and other day-to-day practices. Besides these, boiler units, refrigeration units and effluent treatment also need water. The use of hard water may lead to deposition of salts (scale) on the equipment and therefore, should not be used. Source of water requires attention while selecting a site for an abattoir. 

Electric Supply  

Electricity is required not only for lighting of premises but also essential for a number of mechanical operations. With advancement of the technology, the manual practices have been replaced by mechanical one for which electricity is needed. Boiler plant, refrigeration unit, rendering plant, even lighting at inspection point, chiller etc. all require electricity and therefore, site should have a regular electric supply. 

Effluent Disposal 

An effective system for the disposal or renewal of effluent must be provided. The building should be connected with main sewage line or the effluent disposal scheme has to be based on subsurface irrigation and soak-age. The site should therefore, be free draining and not subject to water logging or flooding. Land used for subsurface irrigation need not necessarily be within the abattoir boundary although control over cropping operations above subsurface irrigation trenches would be essential. 

Geological Structures and Features

Analysis of Soil 

Before constructing an abattoir building, the quality of soil should be examined carefully. The soil should be able to bear the load of structure. It should be suitable for good foundations including piling. Sandy and rock soil as found side by the river is considered unsuitable for good foundations. Similarly area with rock soil is also not a preferred one. 

Level of Site 

The site for an abattoir should be at a higher level compared to its surroundings. It is to prevent accumulation of water around the plant and surroundings. Moreover, location of abattoir at higher level facilitates proper drainage of waste water/effluent water. Lodging of water acts as breeding site for flies, insects etc. 

Accessibility

Availability of Road/Rail Transport 

Abattoir is just similar to a processing plant for which raw materials are animals and the carcass/meat is the processed product.Similar to any industries/processing plant/enterprise it is necessary that raw materials should reach to processing site and ready product should be cleared from there timely. It requires the connectivity of site through road/rail line so that raw and processed product could be transported easily. Your native place may be devoid of any broiler farm or layer farm even though the chicken and egg shops are common. This is what transportation is doing now-a-days. Transport to and from the abattoir by road/rail should be available throughout the year for efficient function. 

Proximity with Production/Market Area 

Of course now-a-days distance has been overcome by better transportation facility even though you must be thinking about concentration of industries in a particular area. In fact while setting an establishment, it is of utmost importance to consider about the production area of raw material as well as market for processed product. Nobody would like to spend much in transportation because besides cost it also affects the quality of product. So abattoir should be situated in such a place where it could get regular supply of animals for slaughter i.e., good availability of stock nearby, have good market for meat or have better connectivity with road/rail for quick and safe despatch. 

Availability of Labor 

The abattoir practices involve extensive labor work. Technical and skilled manpower should be available in nearby area. The abundance of it prevents any type of monopoly which helps engage labors at reasonable wages. 

Selection of Site for an Abattoir

Many of you might have gone to purchase meat for own consumption. Have you observed some uniqueness? If you belong to a rural area you must have seen the places where animal is slaughtered. However, in urban areas the animals are slaughtered at a place and after examination and certification of carcass, it is being transported to retail shop of your residential area in a hygienic way.Slaughterhouse, 'Abattoir' and 'Meat plant' all three are synonymous. By saying slaughter a pity picture of animal, which is bleed to death comes in our mind. Therefore, now-a-days it is in practice to use the term 'abattoir' which is a slaughter house, having license from local authority. Meat plant is similar to abattoir but in most of the cases it is private one, whereas abattoir is supposed to be a public/Government property. 

Again returning to uniqueness of an abattoir/slaughterhouse/meat plant you all must have noticed that usually respect to other premises, it is called site and the site selection is one of the important aspect for any enterprise. 

At the outset it should be ensured if there is a need for a new plant that will operate to the capacity, as inadequate business will lead to serious financial losses. The following points you should consider for selection of a suitable site for an abattoir. 

Slaughter Slab

In rural areas of developing countries, the slaughter of animals for meat consumption is often carried out under less than ideal conditions. In villages and small towns where there are no slaughtering facilities in view of only a few animals are slaughtered, the animals are slaughtered under a tree. The animals are hoisted on tripod bamboo stand for skinning, dressing and evisceration. Meat produced under such conditions lacks veterinary inspection, is often contaminated and must be considered a hazard to human health. Alternately slaughter slab can be built with or without roof observing principles of a regular slaughter house. The slaughter house should have boundary walls and division of semi-clean and clean area of slaughter and evisceration. A permanently installed slaughter slab requires the construction of a concrete floor and a metal roof. The roof gives protection from sun and rain and allows slaughter to take place in all weather. The site should be fenced to prevent access to stray animals and  unauthorized persons. 

A lairage should be constructed for both cattle and small animals. Drinking water should be available for the animals at all the times. There should be floor rings to hold animals, skinning cradles for cattle and small stock, rails for hanging the carcass and an adequate and convenient water supply. The area surrounding the slaughter slab should be paved with concrete or bitumen to improve both sanitary and working conditions.

We recommend in general, stunning and bleeding on clean slaughter slab. Rest of the operation like skinning/dehiding, evisceration can be done on mechanical gravity rail conveyor system.This will be simple, economical for primary processing and maintaining hygiene and sanitation.

Rails for Bleeding, Dressing and Chilling

After stunning, all the other activities like bleeding, dressing and chilling can be either done on floor or on overhead rails.

In rail dressing systems, rails with hooks of suitable rust proof metal and a number of equipment's like hide puller, brisket saw, hock cutter and moving top table etc. should be provided. The rails and hooks should be suitably cleaned and sterilized regularly.

Height and Length of rails for bleeding and dressing

 Space requirement per carcass and the distance between the rails in hanging or chill room 

Construction

During construction of an abattoir/meat plant following points should be considered:

Premises: It is required to be approved and registered by local authorities. While submitting plans for an abattoir, it is usual to submit two sets of drawings and four sets of specification to the responsible authority for approval. The plans include site plan, floor plan and plumbing plan. The site plan must show complete premises and the location in relation to roads, railways, waterways, adjoining properties and their function, catch basins, water and sewer lines, storage tanks etc. The floor plan must explain layout of walls, doorways, windows, partitions, rail system, equipment benches, platforms, toilets, chutes, conveyors, stair cases, hot and cold water connections, ventilation, fans, work positions of operatives, position of drainage gutters and floor gradients etc. The details of drainage system should be in plumbing plan. The plant building floors, walls, ceiling, partitions, doors and all other parts of the structures shall be of such material, construction and finish that they can be readily and thoroughly cleaned.

Roofing: It provides framework of the roof of wood or steel. The roof may be made of corrugated aluminum, asbestos or iron. Galvanized steel plates for the bottom of the doors are used on the outside for protection against rodents.

Construction material: The general principle regarding the choice of materials for constructing slaughterhouse is that the materials must be durable and be able to resist deterioration or destruction from external influences such as the weather. The materials must be impervious to water and blood and not stained by fat. We must consider the use of local materials for building abattoir to minimize the construction cost.

Coves: It provides rounded corner for sanitation at the juncture of walls and floor.

Floor: It should be impervious, non-absorbent, non-slippery and should have suitable gradient for drainage's. To make the non-slippery surface carborundum or aluminum oxide is incorporated.

Interior walls: The walls required to be smooth, flat and constructed of glazed, bricks/tiles or other non-toxic and non-absorbent, durable, light colored material. There should be a washable finish up to height of not less then 3 m from the floor. Wall sheets are often used in the form of plastic laminates, aluminum, polished asbestos, stainless steel or PVC-faced metal free from rust.

Ceilings: It should be of good height, minimum 5 m, smooth and flat, cement plastered, water resistant and impervious to minimize condensation, mould development and easy to clean.

Window ledges: It should slope at 45C to promote sanitation. Window sills should be 1200mm above floor level. There should be mechanical venting in roof structure.

Doorways and doors: It should be at least 2.5 m high, 1.5 m wide and made up of rust resistant metal.

Pest control: The ingress of rats, mice and insects can lead to serious problems as they are carrier of a number of zoonotic diseases. Insect and rodent screens should be provided in abattoir. There should be air curtain at reception, despatch, landing and off loading platform.

Anteroom: There should be an anteroom at main entrance where the air curtain exists.

Vehicular areas: Properly drained and concrete paved areas extended at least 6 m from building or livestock platforms should be provided at places where vehicles are loaded or unloaded. Pressure washing jets and disinfection facilities should be provided for tracks carrying animals.

Drainage: There should be efficient drainage system. All washing's or wet cleaning must course over the slaughter floor into a collecting drainage and empty eventually outside the building. As a general rule, one drainage inlet should be provided for each 37m^2 of floor space and a slope of 20 mm per meter to drainage inlets should be there for usual condition. Suitable removable metal screw plugs should be provided in the floor drains. Floor drains should not be provided in freezer room and dry storage room. Each floor drain should be equipped with a deep seal trap and drainage line should properly be vented to the outside air. Drainage line for toilet, urinal should be separate and drainage systems should discharge into a septic tank. Floor drainage valleys are essential under the dressing rails and such valleys should be 600 mm wide and should slope at 10 mm per meter to drains with the valleys.

Light and ventilation: Abattoir should be constructed in such a way that adequate natural light and ventilation is available. For natural light windows should face to north with provision for glass. Uncolored glass may be used in skylights and windows. The glass area should be approximately one-fourth the floor area of a workroom. Artificial light and ventilation should be provided alternately by mechanical means. The type of lighting must not distort colors. It is generally recommended that the overall intensity of light should not be less then 540 lux (50 ft candles) at all inspection points, 220 lux (20 ft candles) in work rooms and 110 lux (10 ft candles) in other areas. The intensities of light are usually taken at levels of 0.9 m from the floor, except in inspection areas where the height is 1.5 m. Ventilation is necessary to overcome excess heat, steam, condensation, odour, dust accumulation etc. There should be sufficient and suitable means for ventilation to the outside air. Care should be taken    that in no case the dressed carcasses are exposed to direct sunlight.

Water supply: An abattoir should be provided with sufficient, safe, potable and constant supply of fresh chlorinated water with adequate pressure. The water distribution plant may be located at the load centre. A constant supply of clean hot water (not less than 82C) should be available for frequent sterilizing of equipment. Suitable facilities should be there for washing of hands and floors. For fire control, non-potable water should be provided in completely separate lines.

 Average water consumption in an abattoir 

Equipment construction: Equipment should be constructed of rust-resistant metal with smoothness of high quality. Stainless steel, galvanized metal or plastic may be used for this purpose. Where high resistance to corrosive action of food products and cleaning compound is required, galvanized metal should not be used there. Equipment made of copper, cadmium, lead or with painted surface or enamel containers should not be used in the edible product zone. Water-washing equipment such as, soaking and cooking vats, can sterilizers etc. should deliver waste water through an in tempted connection into the drainage system. All equipment's having water on the working surface should be provided with turned up edges. All permanently mounted equipment should be installed sufficiently away from the walls and above the floors to facilitate cleaning and inspection. To provide comfortable working condition to labours, the working table should be at waist height of the workers to work in standing position.

Disposal of abattoir effluent: The volume of waste water from abattoir is 80-85% of the water intake. This waste water typically contains the following contaminated waste material: blood, bits of meat, fat, paunch contents, urine and dung. Each of these waste materials contributes to a high organic load as well as considerable amount of suspended material in the waste water.

source of effluent in an abattoir

The disposal of organic waste from slaughterhouse and the effluent treatment will be discussed in course BPVI.

Plant Layout and Design

We will always look for appropriate plant layout, design and construction for efficient and hygienic production of meat. Therefore, abattoir has to be planned 1 separately for different categories of livestock such as cattle/buffalo, sheep/goat, pig and poultry, keeping in mind the public acceptance and their religious sentiments.

Maximum number of animals and kind of animals to be slaughtered per day is taken into account for layout of plant. During designing an abattoir, we have to consider the purpose of the abattoir, whether it is meant for slaughter and dressing of the animals only or it requires full processing of animals including byproduct processing.

An integrated modem abattoir for export of meat would require around fifty acres of land for lairage, slaughter halls for buffaloes, sheep and goat, chilling, deboning, freezing and cold storage. The capacity of daily production may be around 1000 buffaloes and 10000 sheep/goat. Abattoir for about 400 capacity and 800 capacity animals per day would require two to four acres of land. Careful consideration is to be given to the size and location. 

Smaller plant can be set up close to production area and hence would be economical compared to large meat plants, which are expensive. Many large plants under utilize their capacity due to various reasons such as transport cost, non-availability of enough livestock in and around the location. 

The abattoir shall have the following facilities: 

a) Resting places for animals before slaughter. 

b) Ante-mortem inspection. 

c) Carrying out humane slaughter. 

d) Flaying, dressing and washing of the carcass. 

e) Handling by-products.

f) Inspection of meat and disposal of meat unfit for human consumption.

g) Laboratory. 

h) Staf-welfare

i) Segregation ward for sick/diseased animals. 

j) Adequate water supply. 

Abattoir shall have an adequate separation between clean and unclean section. The sections should be arranged in such a way that from the introduction of a live animal into the abattoir up to the emergence of meat and offal classed as fit for consumption, there shall be a continuous process, without any possibility of reversal, inter-section or over lapping between the live animals and meat, and between meat and by-products or waste.

 Main Components of An Abattoir :

The modern abattoir layout is as follows keeping in view humane method of slaughter and hygienic, wholesome and safe meat production.

(i) Stockyard: It is meant for collection and marketing of livestock in a large number. It should be roofed to protect animals and staff. There should be facility to unload the stock particularly from lorries. All the stock must be handled gently and quietly. As per nature animals prefer walking up slopes rather than down steep gradients and it should be kept in mind while designing stock yard. Stock yard should have enough open area for vehicle turn and usually should be located opposite to the side from where processed product I meat is despatched. Here the animals are examined by veterinarian before sending to lairage. Unless all animals are arriving on hoof, proper ramps for direct unloading of animals from trucks or railway wagons should be provided and the ramps should directly Plant Layout, Design and Construction of An Abattoir lead to ante-mortem area with office room for veterinary inspector. This area should have water and feeding facilities. There should be separate isolation pens with watering and feeding arrangements for (i) animals suspected to be suffering from contagious and infections diseases and (ii) fractious animals in order to segregate them from the remaining animals. Suspected animals are sent to isolation pen directly from stockyard. This area also should have water and feeding facilities. 

(ii)lairage: It is meant to keep two to three days stock for slaughter. After passing through reception area the animals reach to the lairage where these are rested before slaughter. The rest is being given to restore their normal physiological condition. Usually animals travel long distances to reach abattoir and if not rested properly the quality of meat is adversely affected. The lairage should be equipped with all facilities to feel animal comfortable and for this it should be protected from heat, cold and rain. It should be spacious enough (2.8m^2f of each large animal and 1.6m2f or small animals) to accommodate the large animals that will be slaughtered in 2 days and small animals for one day slaughter. Lairage should be provided with abundant water and feed. This section should be so constructed that the animals can be kept separately depending upon their type and class. The lairage should have adequate facilities for ante-mortem inspection. There should also be the separate isolation pens for suspected and fractious animals as in case of stockyard. Where separate lairages are to be provided for livestock meant for different method of slaughter like Halal, Jhatka or Jewish slaughter, complete visual separation shall be effected and entrances shall be kept as far apart as possible.

(iii) Slaughter househall: From lairage, animals are transferred to slaughter hall, which is usually situated at a distance of 10 meter from lairage. Wherever required, separate provisions for slaughtering, dressing and processing of small animals and also for slaughtering of animals under different slaughter method should be made in an abattoir. Exits to such sections should be kept as far apart as possible. It has several sections:

a) Drive/races: Firstly, the animals reach to holding pen and then they are driven to stunning pen through drive/races. Drive is usually a curved path with single file accommodation and stop gate. Animals are continuously being guided by a person to stunning pen.

b) Stunning pen: It is the area where animals are made unconscious before killing. Its design depends on type of stunning procedure to be followed.

c) Bleeding area: Immediately after stunning, the animal has to be bled to death. This area should possess a good gradient for collection of blood. This area should be so located that the blood shall not be splashed on other animals being slaughtered or on the carcass being skinned. Blood drain and collection should be immediate and proper. The minimum diameter of the blood drain shall be 150 mm and-shall be sloped not less than 170 mm per meter to the discharge point. The bleeding trough for large animals shall be at least  1.5 m wide and 1.1-1.2 m for small animals and swine. It should be enclosed on both sides and shall have a smooth impervious surface such as stainless steel. For small stock bleeding area,galvanized steel or aluminium grating shall be provided.For large animals,the overhead bleeding rail should be there. A hand wash basin and knife sterilizer should be provided in this area for the sticker to sterilize knife.

d) Carcass dressing area: In this area a number of operations are carried out such as removal of hide and skin, head removal, evisceration, splitting, trimming and final wash etc. Dressing of carcass should not be done on floor. Adequate means for immediate disposal of hides or skins should be provided. The hides and skins, should never be spread on slaughter floor for inspection. There should be provisions for immediate disposal of legs, horns, hooves etc. Floor wash point, adequate number of hand wash basins with sterilizers and hot and cold water outlets should be provided in this area Sufficient space should be provided for the deborning, removal and thorough washing of heads. If pigs are slaughtered, then the swine scalding tank and dehairing equipment should be separated from the rest of the dressing area. The scalding tank should be equipped with overflow facilities. For a slaughter house with higher slaughter rate (25 or more cattle/hr or 150 or more swine/hr), a moving top evisceration table should be provided with cold water sprays to remove blood and extraneous material and be synchronized with the eviscerating rail. This also should be installed together with the facilities for the systematic removal of all organs and parts. There should be facilities such as racks or trays or equivalent means to accommodate and maintain the identity of organs and parts detained for veterinary diagnosis.

e) Inspection area: Before evisceration the carcass has to be examined carefully for any pathological lesions. Once the carcass is ready for sending to the next section all its visceral organ and the whole eviscerated carcass are reexamined carefully. Then, it is decided whether the carcass has to be sent to chilling section or condemned meat room or detention room, Adequate facilities and space should be there for inspection of the viscera of various types of animals slaughtered. Hand wading, tool sterilization, floor washing and facilities for separation and disposal of condemned material should be provided in this area. Adequate arrangements for identification, inspection and correlation of carcass, viscera and head should be made there.

f) Carcass washing area: A separately drained area or an area of sufficient size slopped to a floor drain should be provided for washing of the approved carcasses with a jet of water. This area should be well curbed

(iv) Cold storage: If the meat is to be consumed immediately after dressing i.e., in hot condition, the carcass has to be sent immediately for sale and cooking. Otherwise in all other cases carcass should be chilled soon after the postmortem inspection. As per EEC regulation, chilling temperature for carcass should not exceed 70°C while for offal it should be below 40°C. Chilling is practiced to set up the meat firmly and check any microbial growth. The carcass is held in chilling room for three days and this process is also known as ageing. All blast freezers and holding freezers should be capable of maintaining temperature of - 25°C or lower and -18°C or lower respectively. There should be provision for measuring relative humidity and temperature. Chill doors should be sliding or single or double-hinged. Internal finishing shall be durable, impervious and with good insulation and floor drainage. All freezers should be equipped with thermographs an facilities for securing with locks.An area in the cooler shall be provided for the chilling and storage of detained carcasses and parts, This area Should be segregated from the remainder of the cooler and shall be equipped with seal and lock.

(v) Cutting and deboning room: Once the carcass is firmly set in chilling room, deboning (separation of meat from bone) becomes easier and cut into pieces. The operation is performed in controlled temperature (10-12°C) area by skilled and efficient worker. An adequate number of knife sanitizers should be provided at strategic locations and the area should have illumination of 220 lux.

(vi) Packaging and despatch section: Adjacent to cutting and deboning room there is packaging room where the meat chunks are packaged and after freezing they are kept under frozen condition (-40°C) before despatch. The despatch area should be adequate in space and shall allow for the orderly and efficient loading of meat into transport vehicle. At the time of loading, docking system is practiced whereby there is no air movement into the despatch area or vehicle.

(vii) Condemned meat room: It is directly connected with inspection area. An adequate space, refrigeration and drainage along with supply of durable and lockable container and weighing facilities are essential in order to arrange for sorting and holding of materials unfit for human consumption prior to despatch. This room should be provided with only one door located outside the building and should be provided with lock. At the planning stage of plant due attention should be given to condemned meat room.

(viii)Detained meat room: Suitable and sufficient facilities should be provided for the isolation of the meat requiring further examinaton as sometime the inspector/veterinarian may be neither in a position to discard the carcass nor to pass it to chilling section. In such cases a detailed report from quality control laboratory and viscera examination section is needed. Detained meat room should be located adjacent to the main slaughter hall inspection point and also to be connected with condemned meat room as well as chilling section and after clearance of pending decision, carcass is accordingly sent. If carcass has to detain for longer time there must be facility for chilling. Enclosure and lock should be provided

(xi) Quality control laboratory: This is meant for detailed examination of specimen from carcass and their respective viscera. Microbiological test, trichinoscopic test etc are conducted here. This area should be well equipped for detail examination of the carcass and the organs because the final decision of acceptance or rejection of the meat and the offals depends on the report of quality control laboratory. This area should be directly connected with the slaughter hall.

Accessories Sections of An Abattoir 

Besides these main components of an abattoir, plant should have following accessories sections:

Blood collection: It is underground to bleeding area and may be divided into two-edible blood collection section and inedible one. Blood has got nutritional as well as commercial importance and it cannot be allowed in waste as in traditional slaughter system.

Hide and skin store: Along with other by products, hide and skin need to be stored before despatch Their safe storage and primary processing needs a separate section.

Gut and tripe room: A separate room and hanging space should be provided for emptying and cleaning of stomach and intestine and this room should have a separate exit. In this area, there may also be a provision for the preparation of casing, tripe and edible fat.

Red offal room: Many of visceral organs have commercial as well as food value. Among these liver, lungs, heart, kidney etc. are the organs which should be trimmed and then placed in a chill or freezing room depending on ultimate system of disposal. The temperature of offal room particularly those to be used as food should not exceed 3°C. This room should be divided into edible and inedible sections for further processing. These sections should be preferably separated from the slaughter floor except for one or two connecting doorways with self closing doors.

Rendering plant: This section deals with extraction of fat from carcass parts, condemned carcass/diseased one by applying high temperature processing. The materials left after fat extraction may be used for animal feed-fertilizer. The whole section of rendering plant my be divided into edible fat section and inedible fat section.

Inedible area: All materials unfit for human consumption with exception of hides and skins should be kept in the section away from edible areas called inedible area.

Equipment wash: An equipment wash section must be designed to avoid buggies, bins and washing of equipment at improper places. The one-way system of passing in equipment, wash section ensures the entry of dirty equipment's entry from one side and exit of only clean equipment's from other side.

Manure bay: A large amount of dung from lairage, emptying of rumen and intestine need a separate section to deal with this huge mass to avoid problem of flies etc. Floors and walls of this area should be impervious, easily washable, properly drained and can be easily disinfected. The floor should be at lower level than other floors in the slaughter-house.

Veterinary office and laboratory: This section should have essential facilities and equipment's to carry out inspection work.

Vehicle washing: There should be separate sections for cleaning of meat transport and animal transport vehicles.

Facilities for personnel: The abattoir building should have well located toilet rooms Sufficiently away from slaughter walls, separate hall with lockers and shower facilities, changing room, adequate facilities for drinking water, washing, canteen and first aid at convenient location, parking areas and security arrangements etc. as per number of staffs. We will read these facilities in detail in the next unit.

Effluent treatment plant: This is the section, which deals with treatment of waste before their safe disposal in environment. We will read this effluent treatment else where in this chapter.

Layout of Modem Abattoir Meat Plan

Plant Layout ,Design and Construction of an Abattoir

We may be aware that present conditions of slaughterhouses are unhygienic and create environmental pollution. The pollution control departments of the State and Central Government face tremendous task to prevent and control pollution arising out of meat industry and to make available hygienic and disease free meat to consumers. 

Abattoir Practices Setting up of modem abattoir and modernization of existing slaughter house will result in benefits as follows: 

• The production of meat and poultry products will be hygienic and wholesome in organized slaughter houses. 
• Illegal and unauthorized slaughter and slaughter of diseased animals will be restricted. 
• Effluent treatment plant and disposal of wastes will prevent surrounding water and air pollution.
• Flies, mosquito menace in the area will be minimized due to disposal of slaughter house wastes hygienically. 
• New opportunity in and around the plant will open up to provide employment. 
• Export of surplus meat will earn valuable foreign exchanges. 
• Primary producer will be benefited by organized marketing and proper grading of livestock. 
• Finally local authorities and Government will fulfill their responsibility to provide hygienic, safe and wholesome meat to consumers. 

The Municipality/Local bodies, State and Central Government, Airport Authorities provide clearance to establish such units. A good plant layout, design and construction ensure: 

• Appropriate maintenance, cleaning and disinfection of plant and building to minimize contamination 
• Surface and material which a in contact with meat a nontoxic, suitably durable and easy to handle, maintain and clean. 
• Facilities are provided for air circulation, temperature and humidity control. 
• Effective control of flies, insects and other pests. 
• Production of safe meat for marketing and human consumption. 

The plant layout, design and construction of an abattoir facilitate for efficient and hygienic processing of meat. It is desirable to have separate abattoir for cattle, sheep, goat, pig and poultry as per local requirements. The number of animals to be slaughtered depends on market requirement of meat and provision for disposal of byproducts, hides, skins, offal's, blood and condemned material. We used to decide the capacity of the abattoir depending on number of factors such as type and number of livestock to be handled, their availability within the range of abattoir, transport cost of live animals and finished meat and meat products to market. Also average age of animal slaughtered and average dressed weight of carcass are important for meat quality and economic returns. 

Mechanized abattoirs have advantage to provide quality meat for domestic use and surplus for export. However, for rural area and small town where the meat is consumed on the same day of slaughter, hot carcass meets the local requirement. 

Species/Breeds of Meat Animals

Introduction:

A group of animals (within a species) related by descent and similar in most characters like general appearance, feature, size, configuration are said to be a "breed". There may be considerable differences between individuals, still they as a group have many common points which distinguish them from other groups or breeds. Thus, breed is a group of animals within a species having common characteristics. The purity of the breed is maintained by confining mating of animals within the breed. A strain is a similar homogenous group having some similarity, but not recognized as a breed. Although we have large number of breeds in each livestock species, majority of the animals in each species are non-descript. Non- descript animals do not belong to any particular breed and repsent the admixture of a number of types which & yet to be purified and fixed by judicial mating programme

Livestock Market

India has over 2000 markets where livestock are traded. There are a few privately owned markets. Meat animals are eventually taken on foot or by truck to the terminal livestock markets, located in close proximity to the slaughterhouses. The animals are sold to meat traders and get slaughtered by them. Livestock markets are under the jurisdiction of the state governments although the direct operation and supervision would generally fall within the preview of the local bodies. State Acts regulate marketing of agricultural produce and the marketing committees are responsible for implementing and enforcing the provisions of the act. The market for live animals in the country unfortunately has not developed on scientific lines.

Some of the constraints of Livestock market are as follows:

• No separate markets for different species of animals. 
• No separate enclosures for different species/animals.
• Market facilities are generally inadequate and poorly maintained. 
• Weighbridges, ramp facilities for loading and unloading, feeding and watering and veterinary facilities are not available. 
• Brokers facilitate most of the trade. Wholesale marketing margins amount to about 30 per cent of the consumer price. 

Export of Meat

India has now started exporting meat particularly to the South-Asian countries. At present, India is exporting meat to more than 60 countries. Buffalo meat constitutes the major item of Indian meat exports due to domestic availability, price differential between domestic and export markets and export policy (buffalo meat is permitted for export while beef is banned). Buffalo meat export is more than 90 per cent of total meat export in quantity terms and 85 per cent in value terms. Export of sheeplgoat meat, pig meat, poultry meat, edible offals and meat products is in small quantities. 

The potential advantages of Indian meat export includes: 

• Large raw material resource 
• Price competitiveness 
• Cheap labor costs 
• Proximity to importing countries and I Preference for Indian lean meat produced on natural grazing and liberalized economic policies.

The export of meat and edible offals from India in 2004-05 is presented in Table  

SourceDirectorate General of Statistics & Commercial Intelligence, Calcutta, (DGCIS), referred by Ministry of agriculture, Govt. of India in Basic Animal Husbandry Statistics, 2006. 

 Export of Meat and Edible Offals in 2004-2005

Future Prospect of Meat Export:

With large animal population, India has good potential to export meat. At present, the major destination of buffalo meat exports are Malaysia, UAE, Jordan, Phillipines, Oman, Mauritius etc., while mutton is exported mainly to UAE, Saudi Arabia, Oman, Bahrain etc. Sheep and goat meat are generally exported in fresh and chilled form whereas, buffalo meat is generally exported in frozen form. Now- a-days, many corporate firms have set up modern integrated meat complexes having state-of-the-art facilities for livestock holding, slaughter, carcass deboning, packing, chiller and frozen storages, by-products processing, effluent treatment etc. Despite of owning about 56 per cent world's buffalo population, 14 per cent of the cattle and goat population of the world, India produce only 2.32 per cent of the total world's meat production (FA0 Statistical Year Book, 2004). The present status of the processed meat industry is not satisfactory. Most of meat is consumed as fresh meat, only two per cent of the total meat is  converted into processed meat products. 

Major constraints affecting India's meat export includes: 

• Animals are not scientifically reared for meat purpose (except broilers). 
• High prevalence of zoonotic and other diseases like Foot and Mouth Disease (FMD), Hemorrhagic Septicaernia (HS), Brucellosis etc., importing countries are not interested in Indian meat. 
• Inadequate modem abattoir facilities, inadequate slaughtering, processing, storage and transport facilities as per international standards. 
• Inadequate quatity control programmes both in the government and meat industry such as HACCP, Risk Assessment and Sanitary and Phytosanitary (SPS) measures. 
• Negative propaganda of some social groups against meat export and 
• Lack of pragmatic slaughter policy for effective utilization of livestock resources

Meat Production

Country is endowed with more than 11  per cent of the World's livestock population comprising of variety of meat animals such as buffalo, goat, sheep, pig, cattle and poultry. Effective utilization of livestock resources is essential for sustainable animal production. The per capita animal protein availability is about 10 grams dry as against (world average of 25 grams dry) the targeted minimum requirement of 20 grams per capita per day for animal protein. Out of this 20 gm, four grams comes from meat and remaining 16 grams from other livestock products. ICMR recommended 34 gram meat/head/day against the availability of only 14 gm meat/head/day . According to ICMR recommendation, for 70% non-vegetarian population in India, the estimated demand of meat for the present population would be 8.68 million tonnes as against the present production of 6.03 million tonnes (FAOSTAT, 2004). Therefore, significant gap exists between the demand and supply of meat and meat products. 

Meat Production in India

Source: FAO, 2006 (FAOSTAT Website). 

In India, meat production is largely a by-product system of livestock production utilizing spent animals at the end of their productive life. Cattle and buffaloes, which contribute about 50 per cent of total meat production, are primarily reared for milk and draught purpose and in the end, utilized for meat purpose subject to many limitations. Buffalo population was less than half of cattle population, but buffalo meat production is equal to that of beef from cattle. This was due to effective utilization of buffalo meat both for domestic anaport market. According to FA0 estimate, 11 per cent buffaloes are slaughtered, but there is sufficient reason to believe that the actual slaughtering rate may be as high as 20 per cent. Buffalo is now used for triple purposes namely, milk, meat and draught. A few states have made laws restricting slaughter of buffalo calves and productive buffalos.

Buffalo calves in urban areas suffer from early death for various reasons. There are millions of buffalo calves that need to be saved from early death. Meat production potential of buffaloes could be considerably increased under an ideal management and efficient production system. 

Cow slaughter is banned largely in the country. However, all the bovine animals can be slaughtered in West Bengal, Assam, Kerala and Tamil Nadu on 'fit-for- slaughter' certificate which is given if animal is over certain age like 10 years, 12 years or 14 years of age and is unfit for work and breeding or has become permanently incapacitated for work and breeding due to injury, deformity or any incurable disease, In Bihar, Andhra Pradesh, Uttar Pradesh, Pondicheny, Orissa, Maharashtra, Karnataka and Goa, male bovine animals can be slaughtered on 'fit-for- slaughter certificate' provided they follow the same condition as already mentioned for the state of West Bengal, Assam etc. The States of Meghalaya and Nagaland do not have any legislation on cow's slaughter. Slaughter of all cattle is totally prohibited in Delhi, Gujamt, Punjab, Haryana, Himachal Mesh, Rajasthan and Jammu and Kashrnir. (Source: http://dahd nic. in/ch2/an2.8. htm). 

Sheep and goat meat has a high domestic demand and returns from sale of skin are considerable due to the growth in leather industry. Slaughter of under-weight lambs/kids is adversely affecting meat production potential which needs to be corrected with appropriate programmes. Sheep and goat, which contribute to considerable domestic meat demand, are mainly reared under extensive and Livestock Population and nomadic system without serious effort for productivity improvement.

Pig rearing has largely remained under nomadic system of rearing (scavenging) with the weaker sections of the society both as a source of income and a choice of meat for consumption. Cost of inputs and returns were not a serious concern in this system. However, availability of quality pork for a variety of consumers is a scarce item. In the recent years, entrepreneurs have shown interest in pig production, processing and marketing activities as an organized enterprise. India could consider exporting pork products, as potential markets exist in South- East Asian countries. 

Poultry industry has grown in more organized manner compared to other livestock species and the country has adapted modem production system. However, meat processing sector is largely under traditional system in spite of increase in volumes of processing. Most of the birds are slaughtered in the roadside butcher shops. Improvements in small-scale processing of poultry are required to process chicken under aesthetic conditions and ensure consumer demand. The poultry processing industry is still in a nascent stage of growth. Presently, 97 per cent of the poultry meat is sold as live birds. Only three per cent is processed and sold as fresh I chilled or frozen. The share of further processed and ready-to-cook products is even lesser at about half-a-per cent. The market for processed chicken is confined to the metro cities and a few large urban areas. This limited market is shared by more than a dozen processors. The obstacles in the way of growth of poultry processing industry are high incidence of duties and    taxes both on the processed products as well as on the equipment for processing and outbreak of the emerging disease like bird flu etc. 

Livestock Population

There has been drastic changes in livestock population over the past 5 years which has been presented in Table 

Let us see the species-wise changes in population: 

Cattle Population 

In India, cattle are fairly distributed all over  the country. Total cattle population has decreased from 204.58 million in 1992 to 185.18 million in 2003.The important changes observed in cattle population are: 

• Cattle constitute about 38.2 % of the livestock population in the country. 
• There has been a marked shift from work  animals towards milch animals.
• Within cattle crossbred cattle constitute 13.3% where as 86.7% are indigenous cattle.
• Crossbred cattle have grown at a much faster rate (22.82 %)than the indigenous stock which has decreased by (-) 10.23 percent. 

         

 Changes in livestock  Population in India over the last 5 years 

Source: DAHD, 2003. 17* Indian Livestock Census. 

• Maximum number of cattle is found in Uttar Pradesh (10.2 %), followed by West Bengal (10.0 %), Madhya Pradesh (10.0 %), Maharashtra (8.6 %),  Orissa (7.4 %), Bihar (7.0 %), Rajasthan (5.8 %), Karnataka (5.1 %) and Andhra Pradesh (5.0 %) . 
• As per the 17th Livestock Census (2003), the total male and female crossbred cattle below 2.5 years is 3.08 and 7.44 million respectively and the corresponding figures for indigenous cattle is 21.85 and 30.75 million, respectively. Majority of the male calves particularly crossbred calves are dying due to starvation and negligence. These calves remain underutilized for meat production, as cattle slaughter is not permitted in most of the states. 

Buffalo Population :

The buffalo population has increased by 8.9 per cent during the period from 89.92 million (1997) to 97.92 million (2003). 

• Buffalo constitute about 20.2 % of the livestock population in the country. 
• As per 17th Livestock census (2003), buffalo is found mostly in Uttar Pradesh (22.3 per cent), Andhra Pradesh (11.0 per cent), Rajasthan (10.8 per cent), Madhya Pradesh (7.8 per cent), Gujarat (7.3 per cent), Haryana (6.3 per cent), Punjab (6.2 per cent), Maharashtra (6 per cent), Bihar (5.5 per cent) and Karnataka (4.1 per cent). 
• Maximum meat production in India comes from buffalo. However, male calves born in the suburban areas (City Dairies) die due to starvation and negligence. They could be saved and reared for meat production. 

Goat Population:

• During last three decades, goat population in India had increased at the fastest rate among all major livestock species, in spite of the fact that more than 30 per cent of goats are slaughtered annually while about 15 per cent die. 
• Goat population reached 124.36 million (2003) from 122.72 million (1997) with an increase of 1.33%. 
• Goats constitute about 25.6 % of the livestock population in the country. 
• According to 17th Livestock census (2003), major goat producing states are West Bengal(15.6 per cent) followed by Rajasthan (14 per cent), Uttar Pradesh (10.3 per cent), Maharashtra (8.5 per cent), Bihar (7.0 per cent), Madhya Pradesh (6.7 per cent), Tamil Nadu (5.3 per cent) and Andhra Pradesh (5.2 per cent). 

Sheep Population: 

• Sheep constitute about 12.7 % of the livestock population in the country. 
• During last three decades, there has not been much increase in sheep population. But in the last decade, sheep population started increasing and reached to about 61.47 million in 2003 compared to about 57 million in 1997 with an increase of 6.91%. 
• As per 17th Livestock census (2003), sheep population is maximum in Andhra Pradesh (35 per cent) followed by Rajasthan (16.4 per cent), Karnataka (12 per cent), Tamil Nadu (9 per cent), Jarnrnu and Kashmir (5.5 per cent), Maharashtra (5 per cent) and Gujarat (3.2 per cent). 

Pig Population: 

• There is an increasing trend in pig population. It was 12.78 million in 1992, 13.29 million in 1997 and 13.52 million in 2003. 
• Pigs constitute only 2.8 % of the livestock population in the country. 
• According to 17th Livestock census (2003), maximum number of pig are found in Uttar Pradesh (1 7 per cent) followed by Assam (11.4 per cent), West Bengal (9.6 per cent) and Jharkhand (8.2 per cent). Pig is very common in north- easter states including Sikkim. 
• Population of crossbred pig is also increasing. It increased at the rate of 2.78 % per annum from 1997 to 2003. Eighty three per cent of total pigs are indigenous. Crossbred pigs are predominant in north-eastern states and Uttar Pradesh. 

Camel, Yak and Mithun Population :

• There is a decreasing trend in camel population whereas, Yak and Mithun population increased in 2003 when compared to 1997 census. 
• Camel population decreased from 9.12 lakh (1997) to 6.32 lakh (2003). 
• Mithun population showed an increasing trend. It increased from 1.77 lakh (1997) to 2.78 lakh(2003). 
• Livestock Population and Meat Production in India 
• Yak population increased from 0.59 lakh (1997) to 0.65 lakh (2003). 

Poultry Population 

• According to 17th Livestock Census (2003), there is sharp increase in the chicken population in the country during the period from 315 million (1997) to 457 million (2003). The population of other birds like ducks has increased marginally, from 32.2 million in 1997 to 31.61 million in 2003. Out of total poultry, around 93.5% are fowls (Chicken) and the rest 6.5% are duck, drakes, ducklings, turkey and other poultry birds. 

 Poultry Population in India as per 17th Indian Livestock Census 

Source: DAHD, 2003. 17th Indian Livestock Census

Livestock Population and Meat Production in India

India has vast resources of livestock, which is growing at a steady rate in the last five decades. To find out the total number of animals in each category of animal, livestock census is being conducted in the country. After Independence, the first livestock census was conducted in 1951 and subsequently it is being canned out every five years. The 1 P Livestock Census: All-India Summary Report (2003) is the last published data released by the Department of Animal Husbandry and Dairying & Government of India The total livestock which includes cattle, buffaloes,sheep, goats, pigs, yaks, million, camels, horses, ponies, mules and donkeys have increased from 293 million in 1951 to 485 million in 2003. Similarly, the poultry population has increased hm 73.5 million (1951) to 489 million (2003).

As per the 1 P Livestock Census (2003), there were 185.18 million cattle (including 24.68 million crossbred cattle), 97.92 million buffaloes, 61.47 million sheep, 124.36 million goat, 13.52 million pigs, 0.28 million mithun, 0.07 million yak and 489.01 million poultry . Population of all the major livestock species is increasing except cattle population, which has declined by (-) 6.89 per cent over 1997 census.

Livestock Population in India

Source: DAHD, 2003. 17'" Indian Livestock Census In the world, India Ranks:

• First in buffalo population
• Second in cattle and goat population
• Third in sheep population and
• Seventh in poultry population

Source: Economic Survey - 2006-2007, Ministry of Finance, Go1

Bacteria in Food

Bacteria make up the largest group of microorganisms and therefore, we will deal the same in details. People often think of them only as germs and the harm they do. Actually, only a small number of bacterial genera are pathogenic (disease causing). Most are harmless and many are beneficial. The bacteria and fungi are most important in relation to food. The most important genera of bacteria known to occur in foods are listed below in alphabetical order:

Acetobacter, Acinetobacter, Aeromonas, Alcaligenes, Alteromonas, Bacillus, Brochothrix, Campylobacter, Citrobacter, Clostridium, Corynebacterium, Entereobacter, Erwinia, Escherichia, Flavobacterium, Lactobacillus, Leuconostoc, Micrococcus, Moraxella, Pediococcus, Proteus, Pseudomonas, Salmonella, Serratta, Shigella, Staphylococcus, Streptococcus, Vibrio and Yersinia.

Some of these are highly desirable in certain foods, while others bring about spoilage or cause food poisoning gastroenteritis in humans. One-third of bacteria causing food poisoning belongs to the family Enterobacteriaceae.

Shapes and Arrangement of Bacteria

There are thousands of different kinds of bacteria. Some differ only slightly and it takes a highly trained person and a number of biochemical tests to identify them. There are also groups, which differ greatly in growth habits and appearance (morphology), and are quite easily identified. But regardless of minor differences, most bacteria can be classified into five basic cell shapes namely cocci (roundshaped), rods (elongated) spirochete (spiral), vibrio (comma-shaped) and filament bacteria (branched). In addition to their different shapes, their cell arrangement also varies. For example, some round-shaped bacteria (cocci) are always grouped in pairs (diplococci), some in chains (streptococci) and some in the form of bunch of grapes (staphylococci). Diplococci are the kind that causes pneumonia. Streptococci are often associated with 'sore throat'. Staphylococci are familiar to many because of their role in infections causing 'pus formation' and some types of 'food poisoning'. Bacteria also vary somewhat in size, but average about 1125,000 inch. In other words, 25,000 bacteria laid side by side would occupy only one inch of space. One cubic inch is big enough to hold nine trillion average size bacteria.

Bacterial Cell Shapes and Arrangements

The replication of bacteria

Bacteria reproduce by a process called 'binary fission', one cell divides and becomes two. Some can reproduce at a very rapid rate under proper conditions. If food and moisture are adequate and the temperature is right, certain bacteria can reproduce within as little as 20 minutes. Within 20 minutes, one cell becomes two and in 40 minutes, there will be four, and so on. In only eight hours, the original cell will have multiplied to nearly 17 million new bacteria. Of course, conditjons don't remain favourable for such a rate of reproduction for long. If they did, we could be burikd in bacterial cells.

Binary Fission

We must use a microscope capable of magnifying 500 times in order to see a single bacterial cell. However, if that cell is allowed to grow on suitable food or solid media, it will reproduce rapidly into a colony consisting of millions of cells. The colony is visible to the naked eye. Plate counting, a technique which makes it possible to determine the number of bacteria (colonies of bacteria grown from single cells) in a food sample without the aid of a microscope. An important thing to consider in the growth ofbacteria is the ability of certain types to produce spores. A 'spore' is a dormant or resting state of a bacterial cell. There are certain basic differences between the spores and the active or vegetative bacterial cells. The spores develop inside vegetative cells at the central, subterminal or terminal (at pole) positions with or without bulging of the cells. Generally, these spores are formed only when environmental conditions are unfavorable for growth. Subsequently, these may be released in the environment as free cells. Spores are not easily killed. In fact, conditions that will quickly kill active bacteria have little or no effect on spores. A temperature of 72OC (pasteurization temperature) will kill bacterial cells within minutes, but bacterial spores can resist this temperature indefinitely. This is important to us since in all processing times for canned foods are calculated by using both the time and temperature required to kill bacterial spores. Bacterial genera producing spores are Clostridiurn and Bacillus.

Bacterial Spores

Environmental and nutritive requirements of bacteria

We know that the availability of oxygen is essential for survival of human beings and animals. However, in case of bacteria, the requirement of oxygen for growth varies greatly. Accordingly, bacteria may be placed into one of the three groups.

The 'aerobic' bacteria thrive in the presence of oxygen and require it for their continued growth and existence. Other bacteria are 'anaerobic' and cannot tolerate gaseous oxygen. such as those bacteria that live in deep underwater sediments or some of those which cause bacterial food poisoning such as botulism. The third group is of 'facultative anaerobes', which prefer growing in the presence of oxygen, but can continue to grow without it.

Bacteria may also be classified on the basis of source of energy. There are two categories: 'heterotrophs' and 'autotrophs' . The 'heterotrophs' derive energy from the breakdown of complex organic compounds available from the environment. It includes 'saprobic or saprophytic' bacteria found in decaying material, as well as those that rely on fermentation or respiration. The other group is called 'autotrophs', which fix carbon-dioxide to make their own food source. They may be fueled by light energy (photoautotrophic) or by oxidation of nitrogen, sulfur, or other elements (chemoautotrophic).

Viewing of bacteria 

Bacteria under microscope can be viewed in a smear (a film) prepared directly from a little amount of food item or a bacterial colony grown on an artificial media. The bacterial cells can be viewed easily under microscope once the smear is stained with special colouring reagents called stains. The most commonly used stain is the Gram's stain. On staining the smear with Gram's stains, the circular forms (cocci) or elongated shapes (rods) of bacteria which take pinklred colour are called as Gram-negative bacteria, while the blue/violet coloured as Gram-positive bacteria.

Classification of bacteria

Depending upon their staining characteristics and shapes, bacteria have been classified into different broad groups (families), specific groups (genus) and closely related members within the groups (species).

A) Gram-positive bacteria

i) Cocci

The family Micrococcaceae includes two genera (singular-genus) of significance i.e., Micrococcus and Staphylococcus. Representative of both the genera can be isolated fiom wide range of foods, of these the micrococci are principally spoilers of salted foods. Members of the family Streptococcaceae are facultative anaerobes and form non-motile cocci that occur typically in chains or tetrads depending upon the method of cell division. Three genera, Streptococcus, Leuconostoc and Pediococcus are involved in food spoilage and the foods involved include bacon, vacuum-packed meats and milk.

ii) Endospore forming rods

The genus Bacillus consists of species that are aerobic and facultatively anaerobic. Bacillus species are very commonly isolated from both raw and cooked foods.

iii) Asporogenous rods

Lactobacillus is the remaining genus comprising 'lactic acid bacteria'. Lactobacilli are non-motile rods that often occur in chains and they are anaerobic or microaerophilic (require small amounts of oxygen for growth). They cause spoilage of variety of foods, but like streptococci, they are used as starter organisms in the food industry.

B) Gram- negative bacteria

i) Spiral and curved bacteria: Only one genus, Campylobacter is significant in foods, being important cause of food poisoning.

ii) Aerobic rods and cocci: Most important genus in this group is Pseudomonas. Many species of this genus grow at low temperature causing food spoilage. Several species produce insoluble yellow, orange or blue pigments but these are not important in foods.

The genera Acetobacter and Alcaligenes occur particularly in dairy products and eggs causing spoilage problems while, genus Brucella cause foodborne illness in man either by contact with animals or typically, by consumption of unpasteurized milk.

iii) Facultative anaerobic rods: These Gram-negative, rod-shaped bacteria grow either under aerobic or anaerobic conditions. Two distinct families are recognized. The first, Enterobacteriaceae, contains eight genera of interest, namely, Escherichia, Salmonella, Shigella, Enterobactel; Serratia, Proteus, firsinia and Erwinia. The second family, Vibrionaceae, contains only two genera of interest, Vibrio and Aeromonas.

All organisms in the family Enterobacteriaceae are either motile with peritrichous flagella or non-motile. There is only one species E. coli, in the genus Escherichia.

It is important as an indicator of faecal pollution but many strains can cause food poisoning.

The members of genus Salmonella in the form of more than 2500 different serotypes are very important cause of food poisoning. The members of Shigella species are fairly related to salmonellae except that the former are non-motile and the latter are predominantly motile. Both genera are primarily associated with man and vertebrates, and Shigella organisms are again pathogenic to man causing food-borne infections.

Yersinia species is of no great significance in foods, but one species enterocolitica, is now recognized as a cause of food poisoning in man. The remaining genera, Serratia, Proteus and Erwinia, are sometimes implicated in food spoilage. Only one species, S. marcescens, is included in Serratia and it is characteristically pigmented bright red. Proteus species are important in the spoilage of eggs and raw meats held at ambient temperatures whilest Erwinia species are involved in the spoilage of vegetables.

Family Vibrionaceae contains species that are typically motile with polar (at one end of the cell) flagella. Mbrio species is important in food since different strains cause food poisoning, food-borne infections and food spoilage while Aeromonas are sometimes involved in food spoilage as well as an important fish pathogen.

Genus Flavobacteriurn comprises of yellow-pigmented species that are regularly found on fresh meats and fish. However, their growth tends to be overgrown by other bacteria during spoilage of these foods. It has been implicated in the spoilage of milk and milk products.