GAHP
GAHP
GAHP
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.
GAHP in Broiler Chicken
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
GAHP in Broiler Chicken
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 nonproductive 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
Housing
Open 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.
GAHP in Broiler Chicken
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.
GAHP in Broiler Chicken
• 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
Total soluble solids
Chlorides
Iron
Sulphate
Nitrates
Nitrites
Chlorine
Oxygen
6.5 - 8.0
< 550 ppm
< 250 ppm
< 0.3 ppm
< 250 ppm
< 10 ppm
< 1 ppm
< 0.05 ppm
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 biosecurity 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 biosecurity 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 properly
Use 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.
10.WELFARE OF BIRDS AND WORKERS
• 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
10.WELFARE OF BIRDS AND WORKERS
• 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
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 may
concern:
• 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 5
These documents can be freely downloaded
through the PIC/S website
(www.picscheme.org) under the section
‘Publications’.
ANNEX 4
• MANUFACTURE OF VETERINARY MEDICINAL
PRODUCTS OTHER THAN IMMUNOLOGICALS
• MANUFACTURE OF PREMIXES FOR MEDICATED FEEDING
STUFFS
• 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 surrounded
by 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 the
veterinary medicinal product in accordance with the
guide.
THE MANUFACTURE OF VETERINARY MEDICINAL PRODUCTS
CONTAINING 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 IMMUNOLOGICAL
VETERINARY MEDICAL PRODUCTS (ANNEX 5)
1. Principle
2. Personnel
3. Premises
4. Equipment
5. Production
6. Starting Materials
7. Animals animal houses
8. Disinfection-waste disposal
9. Quality control
MANUFACTURE OF IMMUNOLOGICAL
VETERINARY MEDICAL PRODUCTS (ANNEX 5)
1. Principles
1. 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.
MANUFACTURE OF IMMUNOLOGICAL
VETERINARY MEDICAL PRODUCTS (ANNEX 5)
• 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.
MANUFACTURE OF IMMUNOLOGICAL
VETERINARY MEDICAL PRODUCTS (ANNEX 5)
• 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.
MANUFACTURE OF IMMUNOLOGICAL
VETERINARY MEDICAL PRODUCTS (ANNEX 5)
• 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 particular
requirements 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. These
should 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.
Skeletal Muscle Cell Structure
Skeletal Muscle Cell Structure
• 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
Skeletal Muscle Cell Structure
• 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 resynthesis 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.
Conversion of Muscle to Meat
• 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 breedtype of the animal and how long it was fed in
the feedlot.
Conversion of Muscle to Meat
• 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.
Conversion of Muscle to Meat
• 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.
Conversion of Muscle to Meat
• 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.
Conversion of Muscle to Meat
• 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.
Conversion of Muscle to Meat
• 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.
Conversion of Muscle to Meat
• 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.
Conversion of Muscle to Meat
• 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.
Conversion of Muscle to Meat
• 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.
Conversion of Muscle to Meat
• 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 Resolution of Rigor Mortis and
the Tenderization of Meat
• 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 Resolution of Rigor Mortis and
the Tenderization of Meat
• The process of conditioning
Species
Days at 1C to reach 80% of maximum tenderness
Beef
10
Rabbit
9.5
Sheep
7.7
Pig
4.2
Chicken
0.3
The Resolution of Rigor Mortis and
the Tenderization of Meat
• Recommended conditioning times (days) for
pork, lamb and beef
Pork
4-10
Lamb
7-14
Beef
10-21
The Resolution of Rigor Mortis and
the Tenderization of Meat
• 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 Resolution of Rigor Mortis and
the Tenderization of Meat
• 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.
The Resolution of Rigor Mortis and
the Tenderization of Meat
• 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 to
Meat
• 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