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
CVASU
1

Contents
 Slaughtering of animals
 Processing of animals after slaughter
 Postmortem changes and ageing of
meat
2
CVASU

Slaughtering of animals
 Slaughter: The act of killing or
butchering of animals in a "correct"
way especially for food.
3
Essentials of Slaughter
1. Suffering should be minimum
2. Perfect bleeding should be ensured
CVASU

Treatment of Animal prior to
slaughter
Resting
Watering
Feeding
Fasting
4
CVASU

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
5
CVASU

Watering
 Essential for:
Reduce microbes load in intestine
Facilitated skinning
Electrical stunning is more efficient
6
CVASU

Feeding
 Importance:
Deposition of muscle glycogen
Development of acidity- Increase
keeping quality of meat
Good appearance, taste & tenderness
of meat
7
CVASU

Fasting
 Should stop feeding few hours before
slaughter
 Importance:
Good bleeding carcass
Minimize migration of microbes from
intestine
8
CVASU

Slaughtering practices and
techniques
A. The Humane Method &
Conventional Techniques of
Slaughter
&
B. Traditional and Ritualistic
Slaughter
9
a. African Traditional Slaughter
b. Jewish Method/Shechita
c. Muslim method of slaughter
d. Jhakta (Sikh) method
CVASU

A. The Humane Method &
Conventional Techniques
 Complete state of unconsciousness
-mechanical, electrical or chemical
means (Stunning)
 Stunning-
Painless, Motionless, eliminating
excitement and cruelty
10
CVASU

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
11
Vertical Hanging
CVASU

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
CVASU

Humane Method
 Advantages:
Painlessness (Stunning)
Eliminating excitement and possible
cruelty.
 Disadvantages:
Disallowed by rituals and
established traditions
13
CVASU

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
14
CVASU

15
Captive-bolt pistol
Electric stunner
Aiming point for
stunning cattle
Head tongs are also
suitable for stunning pigs
CVASU

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.
16
CVASU

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.
17
CVASU

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.
18
CVASU

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.
19
CVASU

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
20
CVASU

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.
21
CVASU

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
22
CVASU

Halal method (cont.)
 Advantages
Same as Jewish
Struggling & cardiac action- efficient
bleeding
 Disadvantage
contamination by contents of the
stomach -waste of blood
23
CVASU

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
24
CVASU

Jhakta/Sikh method (cont.)
 Advantages
Easy and quick method
 Disadvantages
Imperfect bleeding
25
CVASU

Processing of
animal after
slaughter
26
CVASU

Processing includes:
Skinning
Evisceration
Splitting
Washing
Dressing of carcasses &
Refrigeration
27
CVASU

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
28
CVASU

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
CVASU

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
CVASU

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
CVASU

32
Fig: Correct
cutting lines
for hide
removal
Fig: Combined method of
skinning
CVASU

33Fig: Cattle are on hanging rail (Vertical method)
CVASU

Evisceration
 In all species care must be taken not
to puncture the viscera
34
Fig: Evisceration of cattle
CVASU

Evisceration of cattle
35
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.
CVASU

Evisceration of small ruminants
36
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
Hind quarterCVASU

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
37
Splitting carcass
down the
vertebral column
CVASU

Carcass splitting in small ruminant
 Generally sold entire
 Can be split by saw or cleaver
 Saw will probably be necessary for
older animals
38
CVASU

Carcass splitting in pig
 Split down the backbone as for cattle
 But the head is generally left intact
39
CVASU

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.
40
CVASU

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
CVASU

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
42
CVASU

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
43
CVASU

44
Stunning
Bleedingon
bleedingrail
Loweringon
skinning
cradle,start
flaying,cut
feet,head&tail
Graduallylifting
uptodressing
rail,continue
flaying
Completionof
flaying,cut
breastbone
Evisceratio
n
Splitting
Sequence of operation (combined method)
CVASU

Sequence of operation (vertical method)
45
Stunning
Bleeding
Transferfrom
bleedingrailto
dressingrail
Mechanical
hidepulling
Evisceratio
n
Splitting
CVASU

SCALDING AND
DEHAIRING OF PIGS
46
CVASU

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
47
CVASU

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
CVASU

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)
49

Acidification of the muscle
 At the death blood circulatory system
fails supply of oxygen, glucose & free
FA to muscles ceases anaerobic
metabolism
50
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)
CVASU

51
Glycoge
n
Fructose 1,6-diphosphate
Glyceraldehyde 3-
phosphate
Dihydroxyacetone
phosphate
Glyceric acid 1,3-
diphosphate
Glycerol 1,3-diphosphate
Glyceric acid 3-
phosphate
Phosphoenol pyruvte
Pyruvate Lactic acid
Fig : Pathway of lactic acid production from glycogen in anaerobic
condition after circulatory failure (Glycogenolysis).
CVASU

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
52
CVASU

53
Fig: The pHu is inversely proportional to the concentration of
the initial glycogen concentration
CVASU

Importance of acidification
54
CVASU

The development of rigor mortis
55Fig: muscle histology
CVASU

Mechanism of muscle
contraction
56
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
CVASU

What happen in rigor mortis?
ATP production stop when acidification develop
57
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
CVASU

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
58
CVASU

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
59
CVASU

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
60

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
CVASU

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
62
CVASU

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
63
CVASU

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
64
CVASU

THANKS
TO
ALL
65
CVASU