WELCOME TO MY
PRESENTATION
Presented by:
Mahabub Alam
MS student in Animal Science
Department of Animal Science and Nutrit...
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...
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...
Watering
 Essential for:
Reduce microbes load in intestine
Facilitated skinning
Electrical stunning is more efficient
...
Feeding
 Importance:
Deposition of muscle glycogen
Development of acidity- Increase
keeping quality of meat
Good appea...
Fasting
 Should stop feeding few hours before
slaughter
 Importance:
Good bleeding carcass
Minimize migration of micro...
Slaughtering practices and
techniques
A. The Humane Method &
Conventional Techniques of
Slaughter
&
B. Traditional and Rit...
A. The Humane Method &
Conventional Techniques
 Complete state of unconsciousness
-mechanical, electrical or chemical
mea...
Steps of Humane Method
1. Stunning: Make unconscious prior to
slaughter
2. Bleeding: vertical hanging position (Head
down)...
Steps of Humane Method (Cont.)
3. Skinning: Removing of skin from the
body
4. Eviscerating: open the animal body
to dislod...
Humane Method
 Advantages:
Painlessness (Stunning)
Eliminating excitement and possible
cruelty.
 Disadvantages:
Disal...
Stunning in humane Method
 Stunning: Make unconscious prior to
slaughter
 Methods of stunning:
Direct blow to skull usi...
15
Captive-bolt pistol
Electric stunner
Aiming point for
stunning cattle
Head tongs are also
suitable for stunning pigs
CV...
Traditional and Ritualistic
Slaughter
 Defer from Humane Method by:
 Interpretation of the basic tenets
governing them
...
African Traditional Slaughter
 Sheep or goat is first securely held on its
back on the ground by two or three men
while t...
Jewish Method/Shechita
 Formulated by following
the religious taboos
 Kosher: meat - right fulfilling the
requirement of...
The rules of Jewish ritual slaughter
* Must be alive, healthy & have suffered no injury
* Stunning- forbidden
* Diseased o...
Jewish Method/Shechita
 Advantages:
 No cruelty
 respiratory activity, struggle>
oxyhemoglobin > good color meat
 Disa...
Muslim method of slaughter
(Halal method)
 Most widespread
 Laws are derived from the Koran
 welfare of the animals is ...
Rules of halal method
 Uttered - “bismillahi Allahu Akbar''
 Done by - adult sensible Muslim
 Stunning - allowed
 Shou...
Halal method (cont.)
 Advantages
Same as Jewish
Struggling & cardiac action- efficient
bleeding
 Disadvantage
contami...
Jhakta/Sikh method
 Instant decapitation process
 Sikh, Hindu in the India follows
this method.
 Limited to only to she...
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 ...
Skinning of Cattle
Combined horizontal/vertical methods
Head: horn- remove, head-
skinned, Detached head- cutting throug...
Combined methods (cont.)
 Flaying:
Cut skin-along middle line from sticking wound to
tail
Skin brisket & flanks, workin...
Vertical methods
 Modern plants have overhead rails- Hide
removal is carried out on the hanging
carcass
 Operations are ...
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
ra...
Evisceration of small ruminants
36
A small cut is made in the
abdominal cavity wall just
above the brisket
Fingers of the ...
Carcass splitting in cattle
 Work facing the back of the
carcass
 Split the carcass down the
backbone (chine) with a saw...
Carcass splitting in small ruminant
 Generally sold entire
 Can be split by saw or cleaver
 Saw will probably be necess...
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 ...
Carcass dressing
 Objectives:
Remove all damaged or contaminated parts
Standardize the presentation of carcasses
 Reco...
Refrigeration of carcasses
 Objectives:
Retard bacterial growth & extend the shelf-life
 Recommendations:
Chilling mea...
Refrigeration (cont.)
 Humidity and Air current of cooler:
 High air speeds (AS)-rapid cooling but-
evaporating wt losse...
44
Stunning
Bleedingon
bleedingrail
Loweringon
skinning
cradle,start
flaying,cut
feet,head&tail
Graduallylifting
uptodress...
Sequence of operation (vertical method)
45
Stunning
Bleeding
Transferfrom
bleedingrailto
dressingrail
Mechanical
hidepulli...
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:...
DEHAIRING (pig)
 Done by bell scraper or knife/
 Dip the pig in a bath containing a hot resin
adhesive:
The pig is remo...
Postmortem changes and
ageing of meat
These includes:
Acidification of the muscle after
animal the animal is killed
The...
Acidification of the muscle
 At the death blood circulatory system
fails supply of oxygen, glucose & free
FA to muscles c...
51
Glycoge
n
Fructose 1,6-diphosphate
Glyceraldehyde 3-
phosphate
Dihydroxyacetone
phosphate
Glyceric acid 1,3-
diphosphat...
Acidification of the muscle
(cont.)
 The process of acidification normally
takes 4–8 h in pigs, 12–24 h in sheep
and 15–3...
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 ...
What happen in rigor mortis?
ATP production stop when acidification develop
57
The actinomyosin persist because , ATP requ...
Resolution of rigor and
tenderization of meat
 The myofibrils become fragmented by
controlled homogenization of the
muscl...
The rate of tenderization
 Varies with temperature %& species
 faster at higher temperatures
 80% tenderness:
 About 8...
The process of conditioning
 Conditioning is the term applied to this
natural process of tenderization
 Two types of pro...
The mechanism of tenderization
 Activity of the proteolytic enzymes-
Calpains and cathepsins
 Calpains is more important...
DFD meat
 Color of flesh is darker and drier than
normal
 Occurs in cattle: Pre-slaughter stress
 Normal animal pH fall...
PSE meat
 In stress susceptible animals PH falls
to 5.8-5.6 when the carcass is warm
 Found in pork
 Resulting meat app...
References
 Meat Science An Introductory Text by- P.D.
Warriss
 Meat Hygiene by- J. F. Gracey, D. S. Collins
& R. J. Hue...
THANKS
TO
ALL
65
CVASU
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Methods of slaughtering, processing & postmortem changes and ageing of meat

  1. 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 CVASU 1
  2. 2. Contents  Slaughtering of animals  Processing of animals after slaughter  Postmortem changes and ageing of meat 2 CVASU
  3. 3. 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
  4. 4. Treatment of Animal prior to slaughter Resting Watering Feeding Fasting 4 CVASU
  5. 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 5 CVASU
  6. 6. Watering  Essential for: Reduce microbes load in intestine Facilitated skinning Electrical stunning is more efficient 6 CVASU
  7. 7. Feeding  Importance: Deposition of muscle glycogen Development of acidity- Increase keeping quality of meat Good appearance, taste & tenderness of meat 7 CVASU
  8. 8. Fasting  Should stop feeding few hours before slaughter  Importance: Good bleeding carcass Minimize migration of microbes from intestine 8 CVASU
  9. 9. 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
  10. 10. 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
  11. 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 11 Vertical Hanging CVASU
  12. 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 CVASU
  13. 13. Humane Method  Advantages: Painlessness (Stunning) Eliminating excitement and possible cruelty.  Disadvantages: Disallowed by rituals and established traditions 13 CVASU
  14. 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 14 CVASU
  15. 15. 15 Captive-bolt pistol Electric stunner Aiming point for stunning cattle Head tongs are also suitable for stunning pigs CVASU
  16. 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. 16 CVASU
  17. 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. 17 CVASU
  18. 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. 18 CVASU
  19. 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. 19 CVASU
  20. 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 20 CVASU
  21. 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. 21 CVASU
  22. 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 22 CVASU
  23. 23. Halal method (cont.)  Advantages Same as Jewish Struggling & cardiac action- efficient bleeding  Disadvantage contamination by contents of the stomach -waste of blood 23 CVASU
  24. 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 24 CVASU
  25. 25. Jhakta/Sikh method (cont.)  Advantages Easy and quick method  Disadvantages Imperfect bleeding 25 CVASU
  26. 26. Processing of animal after slaughter 26 CVASU
  27. 27. Processing includes: Skinning Evisceration Splitting Washing Dressing of carcasses & Refrigeration 27 CVASU
  28. 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 28 CVASU
  29. 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 CVASU
  30. 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 CVASU
  31. 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 CVASU
  32. 32. 32 Fig: Correct cutting lines for hide removal Fig: Combined method of skinning CVASU
  33. 33. 33Fig: Cattle are on hanging rail (Vertical method) CVASU
  34. 34. Evisceration  In all species care must be taken not to puncture the viscera 34 Fig: Evisceration of cattle CVASU
  35. 35. 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
  36. 36. 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
  37. 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 37 Splitting carcass down the vertebral column CVASU
  38. 38. 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
  39. 39. Carcass splitting in pig  Split down the backbone as for cattle  But the head is generally left intact 39 CVASU
  40. 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. 40 CVASU
  41. 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 CVASU
  42. 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 42 CVASU
  43. 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 43 CVASU
  44. 44. 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
  45. 45. Sequence of operation (vertical method) 45 Stunning Bleeding Transferfrom bleedingrailto dressingrail Mechanical hidepulling Evisceratio n Splitting CVASU
  46. 46. SCALDING AND DEHAIRING OF PIGS 46 CVASU
  47. 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 47 CVASU
  48. 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 CVASU
  49. 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) 49
  50. 50. 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. 51. 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
  52. 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 52 CVASU
  53. 53. 53 Fig: The pHu is inversely proportional to the concentration of the initial glycogen concentration CVASU
  54. 54. Importance of acidification 54 CVASU
  55. 55. The development of rigor mortis 55Fig: muscle histology CVASU
  56. 56. 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
  57. 57. 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
  58. 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 58 CVASU
  59. 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 59 CVASU
  60. 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 60
  61. 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 CVASU
  62. 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 62 CVASU
  63. 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 63 CVASU
  64. 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 64 CVASU
  65. 65. THANKS TO ALL 65 CVASU

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