This presentation provides information on slaughtering animals and meat processing. It discusses the humane slaughter method which involves stunning, bleeding, skinning, eviscerating, and refrigerating carcasses. Traditional methods like Jewish shechita, Muslim halal, and Sikh jhatka are also described. The document outlines the proper treatment of animals prior to slaughter through resting, watering, feeding, and fasting. The steps of slaughtering cattle and small ruminants are explained in detail along with skinning, evisceration, splitting, washing, and dressing carcasses. Postmortem changes like acidification and rigor mortis that affect meat quality are also summarized.
Methods of slaughtering, processing & postmortem changes and ageing of meat
1. WELCOME TO MY
PRESENTATION
Presented by:
Mahabub Alam
MS student in Animal Science
Department of Animal Science and Nutrition
Chittagong Veterinary and Animal Sciences
University,
Khulshi, Chittagong -4202
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2. Contents
Slaughtering of animals
Processing of animals after slaughter
Postmortem changes and ageing of
meat
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3. Slaughtering of animals
Slaughter: The act of killing or
butchering of animals in a "correct"
way especially for food.
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Essentials of Slaughter
1. Suffering should be minimum
2. Perfect bleeding should be ensured
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4. Treatment of Animal prior to
slaughter
Resting
Watering
Feeding
Fasting
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5. Resting
Keeping quality of meat reduced
without adequate resting due to:
Incomplete development of acidity
Invasion of microbes from intestine
Period of rest:
Depending on species, age, sex & breed
Usually 12-24 hours
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7. Feeding
Importance:
Deposition of muscle glycogen
Development of acidity- Increase
keeping quality of meat
Good appearance, taste & tenderness
of meat
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8. Fasting
Should stop feeding few hours before
slaughter
Importance:
Good bleeding carcass
Minimize migration of microbes from
intestine
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9. Slaughtering practices and
techniques
A. The Humane Method &
Conventional Techniques of
Slaughter
&
B. Traditional and Ritualistic
Slaughter
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a. African Traditional Slaughter
b. Jewish Method/Shechita
c. Muslim method of slaughter
d. Jhakta (Sikh) method
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10. A. The Humane Method &
Conventional Techniques
Complete state of unconsciousness
-mechanical, electrical or chemical
means (Stunning)
Stunning-
Painless, Motionless, eliminating
excitement and cruelty
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11. Steps of Humane Method
1. Stunning: Make unconscious prior to
slaughter
2. Bleeding: vertical hanging position (Head
down),
- knife through the neck behind the jaw
bone and below the first neck bone
- sever the blood vessels of
the neck and let out blood
- bleeding should be as
complete as possible
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Vertical Hanging
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12. Steps of Humane Method (Cont.)
3. Skinning: Removing of skin from the
body
4. Eviscerating: open the animal body
to dislodge the contents and produce
the carcass
5. Postmortem Inspection: Carried out
by professional veterinarians
6. Special Measures: Stamped as –
INSPECTED/ PASSED/
CONDEMNED 12
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13. Humane Method
Advantages:
Painlessness (Stunning)
Eliminating excitement and possible
cruelty.
Disadvantages:
Disallowed by rituals and
established traditions
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14. Stunning in humane Method
Stunning: Make unconscious prior to
slaughter
Methods of stunning:
Direct blow to skull using a club- sheep &
goats
Free bullet fired from a pistol into the skull –
cattle & Horse (unsafe)
Captive-bolt pistols – Cattle & horse (safe)
Electrical stunning- 60–80 V for few seconds
Carbon dioxide stunning- 85% for 45s, used
in pig
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16. Traditional and Ritualistic
Slaughter
Defer from Humane Method by:
Interpretation of the basic tenets
governing them
The animals must be in a state of
consciousness at the time they are
bled
The bleeding must also be
complete.
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17. African Traditional Slaughter
Sheep or goat is first securely held on its
back on the ground by two or three men
while the mouth is grabbed tight and
drawn backwards to stretch the neck
The slaughterer then cuts the throat
transversely with a series of strokes half-
way deep into the neck
Blood is allowed to drain
off until the animal
(still tightly held) is motionless
or dies. The head is then
severed off completely.
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18. Jewish Method/Shechita
Formulated by following
the religious taboos
Kosher: meat - right fulfilling the
requirement of Jewish law-specified in
the Talmud
Shochet: person appointed for
slaughtering
Shomer: person appointed
for limbs and meat processing and seal.
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19. The rules of Jewish ritual slaughter
* Must be alive, healthy & have suffered no injury
* Stunning- forbidden
* Diseased or lesion in meat (Terefa)- unfit for consumption
* Animals that lie & cannot be made to rise must not be
slaughtered
* Slaughter the animals with a single deliberate swift
action of razor sharp knife.
* Structures severed: including the CA& JV
* Neck incision-complete, without
pause, pressure, stabbing, slanting or tearing
* Post mortem examination by Shochet making an incision
posterior to the xiphoid process inserting the arm to
detect any adhesion in the thoracic cavity.
* Kosher -must be sold out within 3 days.
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20. Jewish Method/Shechita
Advantages:
No cruelty
respiratory activity, struggle>
oxyhemoglobin > good color meat
Disadvantages:
Animal remainconscious for a considerable
time
No stunning- Inhuman (many people)
Economic loss
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21. Muslim method of slaughter
(Halal method)
Most widespread
Laws are derived from the Koran
welfare of the animals is a major
consideration (Jewish faith also apply to
Muslims)
Death animals, consumptions of blood
and swine is forbidden.
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22. Rules of halal method
Uttered - “bismillahi Allahu Akbar''
Done by - adult sensible Muslim
Stunning - allowed
Should done quickly
Casting- laid on its back
Neck vessels and passages
(oesphagus and trachea) are severed
by a single slash of a sharp knife
must not - in the sight of the beast
Prior to killing – should feed water
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23. Halal method (cont.)
Advantages
Same as Jewish
Struggling & cardiac action- efficient
bleeding
Disadvantage
contamination by contents of the
stomach -waste of blood
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24. Jhakta/Sikh method
Instant decapitation process
Sikh, Hindu in the India follows
this method.
Limited to only to sheep and
goats
By only one blow head is
separated
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28. Skinning of animals
Precautions:
Outer side of the skin must never
touch the skinned surface
Operators must not touch the
skinned surface with the hand
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29. Skinning of Cattle
Combined horizontal/vertical methods
Head: horn- remove, head-
skinned, Detached head- cutting through
occipital joint, Hang head- on a hook (Hanging
animal)
Lower the carcass on its back- dressing
cradle
Legs:
Skin & remove the legs at carpal & tarsal
Hooves may be left attached to the hide
Forelegs should skinned after carcass is
lowered on to the dressing cradle – to avoid 29
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30. Combined methods (cont.)
Flaying:
Cut skin-along middle line from sticking wound to
tail
Skin brisket & flanks, working backwards
toward the round – with long strokes & keeping
knife up to prevent cuts
Skin udders-without puncturing glandular tissue
Raise the carcass: half-hoist position shoulders
resting on cradle & rump at good height.
Anal region:
Clear skin carefully from around anus avoiding
puncturing it
Cut abdominal wall carefully around rectum
Tie off with twine to seal it
Skin the tail, raise carcass free of floor & finish
flaying 30
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31. Vertical methods
Modern plants have overhead rails- Hide
removal is carried out on the hanging
carcass
Operations are similar to combined
method
It is not possible to reach the hide from
ground level more than one operator is
needed
Single operator-work with hydraulic
platform
Automatic hide pullers - high-throughput 31
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34. Evisceration
In all species care must be taken not
to puncture the viscera
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Fig: Evisceration of cattle
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35. Evisceration of cattle
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combined horizontal/
vertical system
brisket is sawn
along midline when
the carcass on
cradle
raised to half-hoist
position and
abdominal cavity is cut
carefully along middle
line.
carcass is then fully hoisted
to hang so that the viscera
fall out under their own
weight
Separated into
thoracic
viscera, paunch &
intestines
Vertical
system
Carcass is cut
along midline
through brisket &
abdomen
Viscera will come out
as the carcass in
hanging position
Stomachs or intestines if use for consumption they
should tie separately.
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36. Evisceration of small ruminants
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A small cut is made in the
abdominal cavity wall just
above the brisket
Fingers of the other hand are
inserted to lift the body wall
away from the viscera
cut is continued to within about
5 cm of the udder
The omentum is withdrawn &
viscera taken out
breastbone is split down the
middle & thoracic organs then
removed
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37. Carcass splitting in cattle
Work facing the back of the
carcass
Split the carcass down the
backbone (chine) with a saw
or cleaver from the pelvis to
the neck
If a cleaver is used, it may be
necessary to saw through the
rump and loin in older animals
The saw and cleaver should
be sterilized in hot (82°C)
water between carcasses
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Splitting carcass
down the
vertebral column
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38. Carcass splitting in small ruminant
Generally sold entire
Can be split by saw or cleaver
Saw will probably be necessary for
older animals
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39. Carcass splitting in pig
Split down the backbone as for cattle
But the head is generally left intact
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40. Carcass washing
Objectives:
Remove visible soiling
& blood stains
Improve appearance
after chilling
• Recommendations :
Water must be clean
Soiled carcasses should be sprayed
immediately before the soiling material dries
Remove stains from the skinned
surface, internal surface, sticking wound &
pelvic region.
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41. Carcass dressing
Objectives:
Remove all damaged or contaminated parts
Standardize the presentation of carcasses
Recommendations:
Inspection should be done by veterinarian
Signs of disease/damage - entire carcass/offal
may be condemned
Factory personnel must not remove any diseased
parts until they have been seen by the inspector
otherwise they may mask a general condition
which should result in the whole carcass being
condemned.
Any instructions from the inspector to remove and
destroy certain parts must be obeyed. 41
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42. Refrigeration of carcasses
Objectives:
Retard bacterial growth & extend the shelf-life
Recommendations:
Chilling meat after postmortem down to 0°C &
keeping it cold will give a shelf-life of up to three
weeks
Must be placed in the cooler immediately
Must hang on rails & never touch the floor
deep muscle temperature of 6–7° C should be
achieved within:
28 to 36 hours in beef
12 to 16 hours for pork
24 to 30 hours for mutton
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43. Refrigeration (cont.)
Humidity and Air current of cooler:
High air speeds (AS)-rapid cooling but-
evaporating wt losses
High RH- condensation on the carcass surface
favouring mould and bacteria growth
Optimum RH=90% & AS=0.5m/s
Cooler-thoroughly washed before refilling
Personnel handling - should follow the strictest
hygiene
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47. SCALDING (pig)
Scalding in 60°C for about
six minutes
Low temperature: hair will
not be loosened
high a temperature: skin cooked and
the hair difficult to remove
simplest equipment consists of a tank of hot water into
which the pig is lowered by a hoist
To reduce contamination, scalding water should be
changed frequently
Effectiveness scald-hair comes away easily in rubbing
with thumb
Thermostatic controls and timers
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48. DEHAIRING (pig)
Done by bell scraper or knife/
Dip the pig in a bath containing a hot resin
adhesive:
The pig is removed from the bath when resin is
about to set
Require less & produces a very clean skin
48Fig: Machine contain both hot water bath & scraper
Water
bath
Scrap
er
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49. Postmortem changes and
ageing of meat
These includes:
Acidification of the muscle after
animal the animal is killed
The development of rigor mortis
The resolution of rigor and
The tenderization of meat (due to
ageing)
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50. Acidification of the muscle
At the death blood circulatory system
fails supply of oxygen, glucose & free
FA to muscles ceases anaerobic
metabolism
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ATP : regenerated through breakdown of glycogen by
glycolysis
oxidative decarboxylation & phosphorylation will stop
Glycogen broken down in anaerobic condition so LA
accumulates (can not remove by circulation)
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52. Acidification of the muscle
(cont.)
The process of acidification normally
takes 4–8 h in pigs, 12–24 h in sheep
and 15–36 h in cattle
Poultry meat the initial pH fall may be
relatively rapid- in turkeys breast
muscle pH fall to 6 by 10–15
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53. 53
Fig: The pHu is inversely proportional to the concentration of
the initial glycogen concentration
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56. Mechanism of muscle
contraction
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ATP interacts with a thick filament
head
Head to extend into what is called it's "high energy position
Release of Ca from sarcoplasmic reticulum
Ca attach to actin filaments causing them to change
shape so that docking sites for the myosin filament
heads appear
Myosin filament heads bind to these docking sites
(formation of actomyosin) and undergo a change in
shape that pulls on the thin filament bringing it closer to
the center of the sarcomere
Many sarcomeres contract simultaneously their muscle does
Again ATP binds to myosin head to start the contraction
cycle
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57. What happen in rigor mortis?
ATP production stop when acidification develop
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The actinomyosin persist because , ATP require to
extend the myosin head to remove binding with
actin and start contraction cycle
(ATP also require for releale of Ca)
Development of rigor mortis
Note:
Rigor occurs faster in -
Animals that have undergone violent exercise at
death- quick rigor
longer-term preslaughter stress
Rigor occurs slower in- cold weather
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58. Resolution of rigor and
tenderization of meat
The myofibrils become fragmented by
controlled homogenization of the
muscle in aqueous solutions -can be
measure by ‘myofibrillar fragmentation
index’
Suspensions that are more opalescent
indicate smaller particles, reflecting a
greater fragmentation
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59. The rate of tenderization
Varies with temperature %& species
faster at higher temperatures
80% tenderness:
About 8 h after death of the bird,
whereas beef takes 10 days
These differences in the rate of tenderization
lead to different recommended ‘ageing’ times
prior to cooking the meat
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60. The process of conditioning
Conditioning is the term applied to this
natural process of tenderization
Two types of process:
changes in the connective tissue
Components of the meat or weakening of the
myofibrils
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61. The mechanism of tenderization
Activity of the proteolytic enzymes-
Calpains and cathepsins
Calpains is more important
These are lysosomal and sarcoplasmic
enzyme
These are activated by Ca, so called
calcium-activated sarcoplasmic factor
(CASF)
The degrade troponin-T, some collagen
cross-links and mucopolysaccharides of
the CT ground substance
They degrade actin and myosin below a 61
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62. DFD meat
Color of flesh is darker and drier than
normal
Occurs in cattle: Pre-slaughter stress
Normal animal pH falls to 5.5-5.8 but
in stressed animals falls to 7-6.8
Resulting meet are poor keeping
quality
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63. PSE meat
In stress susceptible animals PH falls
to 5.8-5.6 when the carcass is warm
Found in pork
Resulting meat appears pale, soft
, exudative and unattractive
Occurs due to:
High environmental temp.
Rough ante mortem handling
Fightings
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64. References
Meat Science An Introductory Text by- P.D.
Warriss
Meat Hygiene by- J. F. Gracey, D. S. Collins
& R. J. Huey
FAO official website for slaughtering
practices in large animal
FAO official website for slaughtering
practices in small animal
Google wed engine search
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