gahp. gahp in broiler chicken guideline to a good broiler chicken rearing practice introduction the...

GAHP in Broiler Chicken

• GUIDELINE TO A GOOD BROILER CHICKEN REARING PRACTICE• INTRODUCTION• The current market trend of chicken, irrespective whether international or

local, is getting more and more competitive. Price, quality and cleanliness of products are among the main factors contributing towards a guaranteed market. Public and consumer evaluation about food safety, nature quality, tranquility and animal welfare is also changing. The producer must be sensitive to changes in needs of public and market trend. Hence, methods of farm management should also change. A farm must be managed more competently in order to become more productive, competitive, farm activities environment friendly and products suitable for consumer needs. Animal and workers' welfare needs also must be given due attention. Confidence of public and consumers towards poultry farms need to be established, and with this will assure continuous production and investment returns.


1. MANAGEMENT • Workers' health

– Ensure all workers have good health status. Arrange health examination programme on a periodical basis.

• Duties of workers – Prepare a duty list for each and every worker– Each and every farm worker should be clear about their duty and

responsibility– Supervise, identify weaknesses and take appropriate action for

improvement• Training

– Prepare and carry out training programme for workers from time to time


2. DEVELOPMENT OF A FARM AND FACILITIES • Location

– Location site for the farm should not be within area/region under structural planning and development of district or nearby to areas that have high possibility to be developed for public needs

– Complete and good facilities, (Road accessibility, drainage system, electricity supply and others)good ventilation, not less than 0.5 kilometer distance from nearest poultry farm.

– At least 0.20 kilometer from developed areas like municipality, industrial, tourist attractions, public places and facilities.

– Not nearby lakes, ponds and others that are always stopped at by migratory birds

GAHP in Broiler Chicken• Pens :Pens should be built in areas separated from non-

productive areas and fenced up to separate the two.• Not in close proximity with roads frequently used for

transportation of chickens.• Design, size, construction and materials used permit:

– Optimum ventilation inside pens, comfortable and does not affect growth and health of chickens, as well as comfort and health of workers.

– Effective disinfection work. • Ventilation :

– Temperature inside pens below 30°C (optimum 22-26°C). Humidity rate less than 70 %

– Buildings or trees nearby pens does not obstruct air circulation

HousingOpen house system Close house system

Width Not more than 10 meters Not more than 12 meters

Length Depending on need Not more than 150 meter

Wall to roof height At least 2.7 meter -

Floor to roof height At least 3.6 meter 4 meter

Floor to ceiling height

- 2.1 – 3.0 meter

Ground to floor height

Manual waste collection 1.95 meter

Manual waste collection 1.95 meter

Length of roof side At least 0.9 – 1,2 meter Same

Roof gradient At least 1-20 degree Same

Housing

• Design :• Length axis of pens should be in east-west direction to reduce

effect of direct sunlight on chickens.• Distance between pens at least the same as width of pens• Design is such that chickens are not exposed to injury• Enough exit doors for safety of workers and birds during

emergency. For close house system, should install alarm signal• Plan of Farm

– Prepare a structural plan of farm showing main accessible routes to farm, development of surrounding areas like villages, towns and source of water supply nearby.

– showing location of pens and other farm facilities.


3. FEED • Feed

– Supply from feed mills that observe good manufacturing practice (GMP) or those recognized as its equivalent by the Department of Veterinary Services.

– Store in a place with good ventilation so as not to allow its quality to spoil, growth of fungus and breeding of pests.

– Store in clean, rat and bird proof place.– Do not keep poison materials in feed store.– Do not keep feed too long. For stores with cement or ground

flooring, feed should be kept on a base height not less than 15cm.– Monitor quality of feed and cleanliness from time to time.


• Water: Use water from supply that is clean or treated with chlorine and other sanitizers approved by the Government.

• Avoid contamination. Use covered drinkers that can be easily washed.

• Use drinkers that will not easily rust and not made from materials that can lead to poisoning

• Monitor quality (pH, chemicals, bacteria, metal, odour, colour) from time to time

Contents of good drinking water

• pH 6.5 - 8.0• Total soluble solids < 550 ppm• Chlorides < 250 ppm• Iron < 0.3 ppm• Sulphate < 250 ppm• Nitrates < 10 ppm• Nitrites < 1 ppm• Chlorine < 0.05 ppm• Oxygen 7 - 14

LIVESTOCK

• Chicks – Obtain chicks from breeder farms or hatcheries

accredited by the Department of Veterinary Services or which observe management procedures acknowledged equivalent to accreditation prerequisites.

– Check quality upon arrival.– Should be from same flock or same age. – Chicks from different sources are not to be reared

as one flock.

5. MANAGEMENT OF LIVESTOCK AND EQUIPMENTS

• Management Guide Prepare a farm management guide that includes management of livestock, feeds and water, pens, vaccination, use and maintenance of equipments, animal health and others.

• Put a brief guide on management in each and every pen for workers' easy reference.

• Quality Control Practice daily management, use and maintenance of facilities as well as equipments that will ascertain growth and good quality chicks.

• That will ensure farming does not cause : – pollution and interference to surroundings

• spread of disease • Prepare a quality assurance programme

MANAGEMENT OF LIVESTOCK AND EQUIPMENTS

• Records Farm records should be complete (source of chicks, feeds, death, culling, treatment, vaccination and others). Records should be kept well and updated from time to time.

• Monitoring performance Farm productivity norm indicators as a management guide.

• Evaluate management competence continuously.

6. HEALTH• Health Program Prepare a written document on health programme

for the farm and carry it out properly.• Planning and carrying out of programme supervised closely by a

recognized veterinary consultant. • Assessed and updated from time to time.• Disease Control Monitor disease status in farm on a schedule basis.

Keep complete, orderly and updated records of disease monitoring.• Ascertain farm is free from Newcastle disease, zoonotic diseases

(Highly Pathogenic Avian Influenza and Vancomycin Resistant Enterococci and diseases carried through feeds (Salmonellosis, E.coli 157, Campylobacter, Lysteria).

• Take immediate action to control its spread when a disease occurs in the farm.

Health

• Bio-security Prepare a written document on bio-security measures and carry it out properly.

• Provide full and complete facilities for bio-security – Entire boundary of farm to be fenced up at least with 'chain link'

and maintained well.• Have security guard at entrance to farm Facilities for

disinfection (roofed dip for tyres of vehicles and spray, foot bath, bathroom/mist spray). Buildings/structures constructed must ensure disinfection work can be carried out effectively. Facilities that fulfill bio-security requirements for visitors who wish to enter production areas.

Health

• Guide in carrying out bio-security rules and regulations. Only one passage way in and out of production areas used.

• Control system for movement of workers, visitors, vehicles, equipments and goods including baskets, chicks and feed in and out of production areas and between pens to make certain bio-security protocol stipulated is followed.

• Close house system where air sucked out from one house does not direct straight to next house.

• Bio-security rules and regulations put up in strategic places in the farm for attention of workers. Effectiveness of bio-security protocol monitored and evaluated from time to time and make improvements where necessary.

Health

• Drug, Poison and Chemicals Usage, handling and storage according to directions from manufacturers. Dosage, expiry date and storage place followed.

• Only keep quantity deemed enough for use within certain period of time before its expiry date.

• Only use those endorsed by the Government.

Vaccine and Vaccination Programme

Age Type of vaccine Method

1 day ND+IB Intranasal

7days ND+IB Intranasal

14 days IBD Oral

21 days ND+IB Oral

Prepare a written document on vaccination programme and carry it out properlyUse appropriate vaccine.Vaccines kept, handled and used according to directions from manufacturers.Do not use balance of vaccines already opened.Use only vaccines approved by the Government .Monitor effectiveness of vaccination done.

Health

• Disinfection Pens disinfected thoroughly after every production cycle and left empty for a suitable period of time (can stop breeding cycle of disease carrier) before a new flock is brought in.

• All farm equipments disinfected thoroughly after use and kept in a clean and dry place.

• Monitor effectiveness of disinfection work carried out.

7. SANITATION• Cleanliness

– Always keep farm premises and surroundings clean.– Maintenance of growth and grasses in farm.– Maintenance of drainage system.

• Disposal of Farm Waste – Dispose of dead chickens, pen litter and rubbish without delay. Practice

proper disposal system: bury in holes with suitable depth, cover, burn in enclosed places and compose fertilizers out of these waste materials.

– Dead chickens collected and handled properly to avoid possibility of spread of disease.

– Ensure method of disposal does not pollute surroundings and disrupt public tranquility.

– Special place for disposal far away from pens and source of water supply.

PESTS CONTROL

• Control Protocol Prepare a written document on control and carry it out properly. Evaluate effectiveness of protocol from time to time and improve if necessary.

• Construction of Pens and Store Bird and rat proof• Materials used, size and assembling to ensure birds

cannot enter pens. Periodical checks to make sure always in good condition.

• Make sure there's no place in the farm that will attract rats and birds to make their nests.

PESTS CONTROL

• Trees and Growth Trees that attracts birds to farm are not encouraged to be planted surrounding pens. Trees nearby should have branches well maintained.

• Control of Rats Monitor infestation of rats from time to time and keep complete records.

• Take steps to ensure rat index is not more than 10.• Take control measures if index is higher than this

number.

Rodent control• DeTour• DeTour for Rodents is a CONTACT repellent. DeTour will not harm

rodents. It is a contact irritant. In order for it to work it must be placed in areas where rodents will come in contact with it and get the product on them. Once a Rodent has come in contact with the product they will desire to exit the structure and will start looking for ways to get away from the area.

9. POLLUTION CONTROL

• Flies :Take measures so that fly infestation in the farm is at a minimum level. Draw up a fly control program and carry it out properly.

• Monitor fly infestation at all stages of rearing periodically and keep complete records of fly index (use Scuder fly grill); must not be more than 10. Take control measures if index is higher than this number.

• Smell: Take measures so that smell from farm does not disrupt tranquility of surroundings at any time.

• Take appropriate action on anything that may be a source of bad smell in farm and surroundings without delay.

9. POLLUTION CONTROL

• Dust Ensure air sucked out from close house system does not pollute air and disrupt surrounding areas.

• Noise Noise from farm activities and equipments used does not bother public in surroundings.

10.WELFARE OF BIRDS AND WORKERS

• Livestock Management Chickens are free from stress, injury and discomfort on arrival at farm and whole period of rearing, catching and transportation. – Chickens get adequate water and nutritive feed– Conform to stage of growth at all times – Adequate shelter and protection from weather that can be detrimental to

health– Suitable temperature according to stage of growth – Each chicken gets floor space in accordance with stage of growth

• Each chicken gets water ad feeding space and at a height in accordance with stage of growth. Catch chickens in a way which will not cause injury. Transport using vehicles with good ventilation system. Prepare a contingency plan just in case there's any breakdown in transportation.


• Ventilation Monitor level of ammonia, carbon monoxide, carbon dioxide, hydrogen sulfide and oxygen in closed house system from time to time to ensure it does not affect health of chickens and workers. Gas levels must be as follows:Ammonia below 20 ppm

• Carbon monoxide below 40 ppm• Carbon dioxidebelow 0.3%• Oxygen above 16%• Hydrogen sulfide below 5 ppm


• Facilities for Workers Housing quarters, resting place for food and refreshments provided at a distance at least 15 meters from pens.

• Toilets in housing areas and farm.• Clothing and safety measures for workers in

high risk or accident-prone areas.

Veterinary Health Mark (VHM)

Veterinary Health Mark• The "Veterinary Health Mark" logo is a symbol of

quality awarded to the livestock product processing plant under the Veterinary Inspection and Accreditation Program Department of Veterinary Services, Ministry of Agriculture Malaysia. The Logo also showed that those processing plants has fulfill the Minimum Standard Requirement for "Hygiene and Sanitation", "Quality Assurance and Food Safety" that was set by DVS and confirmed by plant inspection which highlighted more to "Food Safety and Quality System" also "Good Manufacturing Practice Programs".

VHM

• Accredited plants which awarded with the VHM Logo are permitted to use it on their registered products label or packaging only to gain and establish end user confidence on the safety of product and as a way of marketing boost. There's lot more benefits from the accreditation program. In Department Level, Veterinary Certificates application from livestock product producers for exportation can be process immediately. Process of issuing Veterinary Certificates is based on the "Animal Rules 1962" which enable processors to bent on the mandatory rules required by importer countries and plan their exportation program wisely.

VHM

• Participation • Program Participation is open for livestock product

processing plants voluntarily. However, for those plants which running export orientation business are compulsory to participate in order fulfilling request by the importer countries terms that require Veterinary Certificates from Veterinary Authorities of the producers country.

• Application Procedure• Plants that interested to participate in this program must

apply using form that have been created by Headquarters of Department of Veterinary Services, Malaysia.

GMP Guidelines for Veterinary Products

To all manufacturers of veterinary products and to whom it mayconcern:

• Under the Control of Drugs and Cosmetics Regulations (Amendment) 2006, compliance with Good Manufacturing Practice (GMP) is required as one of the conditions to be considered in the evaluation of applications for a Manufacturing License.

• As of 1st January 2002, the National Pharmaceutical Control Bureau, Ministry of Health Malaysia, was accepted as the 26th member of Pharmaceutical Inspection Co-operation Scheme (PIC/S). This is an international co-operation between authorities in country members which provide together an active and constructive co-operation in the field of Good Manufacturing Practice (GMP) and related areas towards promoting quality inspection of pharmaceutical factories / manufacturers.

GMP Guidelines for Veterinary Products

• 1) PIC/S GMP Guide (Part 1 : Basic Requirements for Medicinal Products)2) PIC/S GMP Guide (Annexes) – Annex 4 and Annex 5These documents can be freely downloaded through the PIC/S website(www.picscheme.org) under the section ‘Publications’.

ANNEX 4

• MANUFACTURE OF VETERINARY MEDICINALPRODUCTS OTHER THAN IMMUNOLOGICALS

• MANUFACTURE OF PREMIXES FOR MEDICATED FEEDINGSTUFFS

• For the purposes of these paragraphs,A medicated feeding stuff is any mixture of a veterinary medicinal product or products and feed or feeds which is ready prepared for marketing and intended to be fed to animals without further processing because of its curative or preventative properties or other properties (e.g. medical diagnosis, restoration, correction or modification of physiological functions in animals):

ANNEX 4

• A pre-mix for medicated feeding stuffs is any veterinary medicinal product prepared in advance with a view to the subsequent manufacture of medicated feeding stuffs.

• 1. The manufacture of premixes for medicated feeding stuffs requires the use of large quantities of vegetable matter which is likely to attract insects and rodents.

• Premises should be designed, equipped and operated to minimize this risk (point 3.4.) and should also be subject to a regular pest control programme.

ANNEX 4

• 2. Because of the large volume of dust generated during the production of bulk material for premixes, specific attention should be given to the need to avoid cross contamination and facilitate cleaning (point 3.14), for example through the installation of sealed transport systems and dust extraction, whenever possible.

• The installation of such systems does not, however, eliminate the need for regular cleaning of production areas.

• 3. Parts of the process likely to have a significant adverse influence on the stability of the active ingredients) (e.g. use of steam in pellet manufacture) should be carried out in an uniform manner from batch to batch.

ANNEX 4

• 4. Consideration should be given to undertake the manufacture of premixes in dedicated areas which, if at all possible, do not form part of a main manufacturing plant. Alternatively, such dedicated areas should be surroundedby a buffer zone in order to minimize the risk of contamination of other manufacturing areas.

THE MANUFACTURE OF ECTOPARASITICIDES

• 5. In derogation from point 3.6, ectoparasiticides for external application to animals, which are veterinary medicinal products, and subject to marketing authorisation, may be produced and filled on a campaign basis in pesticide specific areas.

• However , other categories of veterinary medicinal products should not be produced in such areas.

• 6. Adequate validated cleaning procedures should be employed to prevent cross contamination, and steps should be taken to ensure the secure storage of theveterinary medicinal product in accordance with the guide.

THE MANUFACTURE OF VETERINARY MEDICINAL PRODUCTSCONTAINING PENICILLINS

• 7. The use of penicillins in veterinary medicine does not present the same risks of hypersensitivity in animals as in humans. Although incidents of hypersensitivity have been recorded in horses and dogs, there are other materials which are toxic to certain species, e.g. the ionophore antibiotics in horses. Although desirable, the requirements that such products be manufactured in dedicated, self-contained facilities (point 3.6) may be dispensed with in the case of facilities dedicated to the manufacture of veterinary medicinal products only. However, all necessary measures should be taken to avoid cross contamination and any risk to operator safety in accordance with the guide. In such circumstances, penicillin-containing products should be manufactured on a campaign basis and should be followed by appropriate, validated decontamination and cleaning procedures.

MANUFACTURE OF IMMUNOLOGICALVETERINARY MEDICAL PRODUCTS (ANNEX 5)

1. Principle2. Personnel3. Premises4. Equipment 5. Production6. Starting Materials7. Animals animal houses8. Disinfection-waste disposal9. Quality control

1. Principles1. Medicinal products have special

characteristics.2. Due to the large number of animal species

and related pathogenic agents, the variety of products manufactured is very wide and the volume of manufacture is often low.

3. The role of quality assurance system is of utmost importance.



• Personnel• 1. Training specific to the products with which they

work.2. The personnel should receive training in bacteriology, biology, biometry, chemistry, immunology, medicine, parasitology, pharmacy, pharmacology, virology and veterinary medicine

3. Personnel should be protected against possible infection with the biological agents used in manufacture.


• 4. Adequate measures should be taken to prevent biological agents being taken outside the manufacturing plant.

• 5. For immunological products, the risk of contamination or cross-contamination by personnel is particularly important.


• Premises• 1. Premises should be designed in such a

way as to control both the risk to the product and to the environment.

• 2. Live biological agents should be handled in contained areas.

• 3. Inactivated biological agents should be handled in clean areas.

Equipment

• The equipment used should be designed and constructed so that it meets the particularrequirements for the manufacture of each product.

• Before being put into operation the equipment should be qualified and validated and subsequently be regularly maintained and validated.

Production

• Because of the wide variety of products, the frequently large number of stages involved in the manufacture of immunological veterinary medicinal products and the nature of the biological processes, careful attention must be paid to adherence to validated operating procedures, to the constant monitoring of production at all stages and to in-process controls.

• Additionally, special consideration should be given to starting materials, media and the use of a seed lot system.

Starting materials

• The suitability of starting materials should be clearly defined in written specifications. Theseshould include details of the supplier, the method of manufacture, the geographical origin and the animal species from which the materials are derived. The controls to be applied to starting materials must be included. Microbiological controls are particularly important.

Animal and animal houses

• General requirements for animal quarters, care and quarantine are laid down in Directive 86/609/EEC3.

• Animal houses should be separated from the other production premises and suitably designed.

• The sanitary status of the animals used for production should be defined, monitored, and recorded. Some animals should be handled as defined in specific monographs (e.g. Specific Pathogens Free flocks).

• Animals, biological agents, and tests carried out should be the subject of an identification system so as to prevent any risk of confusion and to control all possible hazards.

Disinfection – Waste disposal

– Disinfection and/or wastes and effluents disposal may be particularly important in the case of manufacture of immunological products. Careful consideration should therefore be given to procedures and equipment aiming at avoiding environmental contamination as well as to their validation or qualification.

• When necessary, two or more fermentors are within a single area.

Quality control

• In-process controls play a specially important role in ensuring the consistency of the quality of biological medicinal products. Those controls which are crucial for the quality (e.g. virus removal) but which cannot be carried out on the finished product, should be performed at an appropriate stage of production. It may be necessary to retain samples of intermediate products in sufficient amount and under appropriate storage conditions to allow repetition or confirmation of a batch control.

Meat Science

• Skeletal Muscle Cell Structure

• Muscle Anatomy • If you were to take one whole muscle and cut through it, you

would find the muscle is covered in a layer of connective muscle tissue known as the Epimysium. The Epimysium protects the muscle from friction against other muscles and bones.

Skeletal Muscle Cell Structure

• It also continues at the end of the muscle to form (along with other connective tissues) the muscles tendon. Looking at the cross section of the muscle you can see bundles of fibres / fibers, known as Fasciculi, which are surrounded by another connective tissue, called the Perimysium. Each Fasciculi contains anywhere between 10 and 100 muscle fibres, depending on a large strong muscle, such as thoses forming your Quadriceps would have a large number of fibers within each bundle. A smaller muscle used for precision movement, such as those in the hand would contain far fewer fibres per Fasciculi.


• Looking at each muscle fiber in detail, you can see they too are covered in a fibrous connective tissue, known as Endomysium which insulates each muscle fiber. Muscle fibers can range from 10 to 80 micrometers in diameter and may be up to 35cm long.

• Beneath the Endomysium and surrounding the muscle fibre is the Sarcolemma which is the fibres cell membrane and beneath this is the Sarcoplasm, which is the cells cytoplasm, a gelatinous fluid which fills most cells.

Contractile apparatus of skeletal muscle


• Within the muscle cells are myofibrils, long rod-like aggregates of myofibrillar proteins. Myofibrils are long thin contractile elements inside the cell that give the characteristic striated pattern. The sarcomere is the unit of muscle structure between the two Z lines. Other bands that can be observed with the light microscope include the A band, I band and Z line. Areas that appear darkest are the Z line and the regions of the A band where thick and thin filaments overlap. The sarcomere length changes depending on the contractile state of the muscle. The thick and thin filaments do not change length, but the degree of overlap between thick and thin filaments changes.

Muscle Contraction

• Many events happen during contraction to allow for cooperative action of individual sarcomeres to generate movement. Some of the events are important in the understanding of the conversion of muscle to meat. The first step in contraction is the transfer of the nerve impulse from the brain to the muscle.

• Through many hormonal and chemical changes an impulse reaches the organelle that stores calcium in the muscle cell. This causes the release of calcium into the sarcoplasm. The calcium interacts with regulatory proteins in the myofibril to allow crossbridges to form between the main contractile proteins, myosin and actin. The calcium also activates enzymes that start energy metabolism. This allows for coordination of energy metabolism with muscle contraction.

Muscle Contraction

• The high energy phosphate compound, adenosine triphosphate (ATP), is hydrolyzed to create the power stroke of contraction and causes the thick filaments to move past the thin filaments and shorten the sarcomere.

• Many sarcomeres shortening together are what causes contraction in the muscle. To break the crossbridge formed between myosin and actin, ATP must be present. If energy is depleted and no ATP can be manufactured from glycogen than no relaxation of the muscle occurs.

Muscle Contraction

• ATP is normally regenerated from glycolysis; the tricarboxylic acid cycle and the electron transport chain in the mitochondria. In muscle, another short-term mechanism is in place. ATP is regenerated from adenosine diphosphate (ADP) and creatine phosphate (CP). This allows for rapid restoration of ATP in contracting muscle. If muscle is working slowly, and oxygen is supplied in adequate amounts, aerobic metabolism and CP breakdown can adequately supply most of its energy requirements.

Muscle Contraction

• However, when muscle is contacting rapidly, its oxygen supply becomes inadequate for support of ATP re-synthesis via aerobic metabolism. Under these conditions of oxygen shortage, a third mechanism, anaerobic metabolism, is able to supply energy for a short time. A major feature of anaerobic metabolism is accumulation of lactic acid. The amount of energy available in this anaerobic route is limited. Lactic acid accumulation in the muscle lowers its pH, and at pH values of less than 6.0 to 6.5, the rate of glycolysis is drastically reduced, with a proportional reduction in ATP re-synthesis. Under these conditions, fatigue develops quite rapidly.

Muscle Contraction

• During muscle's recovery from fatigue, lactic acid that has accumulated is transported out of the muscle via the blood stream, and is converted to glucose in the liver or metabolized to carbon dioxide and water by the heart (via a specialized enzyme system). ATP and CP, the energy stores, are replenished by the process of normal aerobic metabolism. The recovery process may occur quite rapidly for a slight fatigue, but may require extended periods if the fatigue is severe.

Conversion of Muscle to Meat

• Harvest • Cattle are usually harvested between 1.2-2 years of age

depending on the desired carcass composition and management practice used. As animals get older the metabolism shifts from growth to accumulating fat. This fact of life is what feedlot operators take advantage of when feeding animals. The age of the carcass is determined by dentition (teeth) or bone ossification (factor in quality grading). As the animal gets older the cartilaginous tips of the bone turns to bone.


• Different levels of ossification result in the determination of the carcass age. Also as the animal gets older the number of teeth and wear on the teeth changes. Young animals have fewer teeth with sharper edges than do older animals. Carcass weights vary from 250 -700 kg. This of course depends on the breed-type of the animal and how long it was fed in the feedlot.


• The harvest procedure actually starts with the holding pens. Considerable research has been done recently to make the holding pens and handling areas as stress free as possible. The handling pens entering the slaughter plant make the animals enter in single file into the restraining area or knocking pen. In this area, the animal is restrained in a narrow chute to allow for safe stunning. The typical method for stunning in North America is a concussion method using a captive bolt stunner. Stunning is required in the US by the Humane Slaughter Act of 1958 which requires that any meat plants selling meat products to Federal Agencies to slaughter animals in a humane manner.


• This has gradually become a requirement for most plants. The major exceptions would be Kosher (Jewish) and Halal (Muslim) plants. Other countries such as Australia and New Zealand use electrical stunning and immobilization. The animal is rendered unconscious with an electrical current. The goal of stunning is to make the animal insensitive to pain, but the heart needs to remain beating to allow for complete exanguination or bleeding.


• The next few steps in the slaughter process remove the hooves, horns and hide. The hide is removed mechanically. It is very important that the exterior of the hide does not touch the carcass during removal. The head is removed and the lymph nodes and tongue inspected to ensure that the animal was healthy.

• The tongue will then be moved to another portion of the plant and packaged for sale. The carcass is then eviscerated. This is one of the most important steps. It is imperative that the intestinal contents not come into contact with the carcass. This is a cause of fecal contamination.


• The viscera are then inspected to ensure that the carcass is fit for human consumption. Some viscera are recovered for edible uses. The most notable is the recovery of one of the stomachs (tripe) for export to Asian countries. Some plants may use localized steam vacuum for removal of microorganisms at this point and other contamination points along the line. The carcass is then split into two sides and proceeds on to the final wash.


• All animals harvested for human consumption are inspected. That is one of the distinctions between inspection and grading. Animals are inspected live and any animals that appear to be sick will be separated away from the others.

• Postmortem, the head and viscera are inspected for signs of disease especially lymph nodes, lungs and liver. The carcass is also inspected for dirt and hair or bruises that may be on the carcass. Recently, a risked based system called HACCP - Hazard Analysis Critical Control Points has been introduced into the federal slaughter plants.


• This system is used to identify points at which microbial, chemical, or physical hazards can be introduced and what can be done to minimize or total prevent the hazards from being introduced onto or into the carcass. The HACCP program is required in all federal plants in the United States.


• There are several very significant changes that occur in muscle immediately following harvest. The muscle remains functional for some time but because there is no longer a circulating blood supply, oxygen is not conveyed to the muscle and metabolic end-products are not removed. As a result, the muscle utilizes glycogen as an energy source for ATP and in the process generates lactic acid that accumulates.


• Ordinarily, with oxygen present, the energy sources are more completely broken down and excess lactic acid removed via the blood. Without blood circulation oxygen is unavailable for energy production and lactic acid is not removed from the muscle. The accumulation of lactic acid causes an increase in muscle acidity, from a near neutral pH of 6.8-7.2 to about 5.6. The increased acidity causes a loss in water binding ability and causes calcium release that is the trigger for muscle contraction and energy metabolism. As a result, crossbridges are formed between myosin and actin.


• As the concentration of glycogen stored in the muscle goes down, the energy available to keep muscle relaxed is also depleted. Because the ATP and CP are being used up there comes a point at which the crossbridges become permanent (actomyosin) and rigor mortis develops. The events seen in the development of rigor are the decrease in pH, ATP and CP and a concurrent loss in muscle extensibility. The time required to achieve rigor mortis varies with the type of muscle and animal species. Poultry may require only 1 to 2 hours whereas beef is likely to need 20 to 24 hours. There are several factors that can affect the extent of contraction associated with rigor mortis.

The Resolution of Rigor Mortis and the Tenderization of Meat

• The resolution of rigor• The myofibrils become more easily fragmented by controlled

homogenization of the muscle in aqueous solutions and this can be monitored by measurement of the ‘myofibrillar fragmentation index’. In this, the degree of fragmentation is estimated from the opalescence of suspensions of myofibrils of equal protein content. Suspensions that are more opalescent indicate smaller particles, reflecting a greater fragmentation of the myofibrils. With longer times of ageing of the muscles after death of the animal the myofibrillar fragmentation index increases and the meat becomes more tender when it is cooked.


• The rate of tenderization• The rate at which this tenderization occurs varies

with temperature and in the different species. It is faster at higher temperatures. Every 10°C increase results in a more than doubling of the final tenderness achieved in a certain time. Chicken meat achieves 80% of its maximum tenderness about 8 h after death of the bird, whereas beef takes 10 days to reach the same level of tenderness.


• The process of conditioning

Species Days at 1C to reach 80% of maximum tendernessBeef 10

Rabbit 9.5

Sheep 7.7

Pig 4.2

Chicken 0.3


• Recommended conditioning times (days) for pork, lamb and beefPork 4-10

Lamb 7-14

Beef 10-21


• In contrast, larger changes in the myofibrillar component can be seen. The attachments of the thin (actin) filaments to the Z discs show some breakdown and there is an increase in the amount of water-soluble nitrogen compounds. However, the muscle does not become more extensible during conditioning and therefore the conditioning process is not associated with any dissociation of the actomyosin. The thick and thin filaments remain locked together by the myosin cross-bridges. Tenderization is not caused by the filaments regaining the ability to slide over one another.


• The mechanism of tenderization• Tenderization results from the activities of proteolytic

enzymes present in the muscles. Their normal role is in the breakdown and recycling of proteins which occurs continuously in all living tissues. There are two main sorts of enzyme involved, cathepsins and calpains, of which, at least in red meat species and poultry, the calpains are thought to be more important. However, cathepsins may be more important in the post-mortem degradation of fish muscle and possibly in the tenderization that occurs in meat kept at high temperatures.


• Cathepsins occur in the lysosomes in the sarcoplasm. They are released post mortem and have maximum activity in mildly acid conditions. They are known to degrade troponin-T, some collagen cross-links and mucopolysaccharides of the connective tissue ground substance. They only appear to degrade actin and myosin below a pH of 5 so this is unlikely to occur under normal conditions in meat. The calpains are activated by calcium ions and have maximum activity in neutral to alkaline conditions.

Other Changes Occurring in the Conversion of Muscle toMeat

• We have seen that the major changes occurring in muscles after the death of the animal are acidification and the development and resolution of rigor mortis. The acidification affects colour and water holding capacity and the resolution of rigor results in tenderization.

• With time, the juiciness and flavour of the meat after cooking also often improve, although the reasons for this are poorly understood. Bejerholm (1991) assessed the effects of ageing pork for up to 6 days. All characteristics improved significantly with longer times with the greatest effects between 2 and 3 days.

Effects of ageing pork on eating quality

Ageing time (days)

1 2 3 4

Tenderness -0.2 0 1.0 1.6

Juiciness 1.4 1.3 1.8 2.2

Flavour 1.9 1.8 2.2 2.3

Overall acceptability 0.4 0.6 1.5 1.8

a Slices of pork loin grilled to a final temperature of 65⁰C and scored using 11-point scales, where 5 was ideal, 0 was neither good nor bad and -5 poor.

a

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