2. Introduction
• According to the Food and drug Association meat is that which
is derived from the muscle of animals, closely related to man
biochemically and is of high nutritive value or simply Meat is
animal flesh that is eaten as food
• Following the death of the animal or fish, many biochemical
and physical changes occur leading to the development of post
mortem tenderness.
• An understanding of these changes contribute to high quality
fish or meat products.
3. STRUCTURE OF MUSCLE
TISSUE
• Animal musculature is mostly of Mesodermal origin. There are
more than 300 muscles in the animal body.
• In addition to the skeletal muscle, which forms the bulk of
meat, a little of smooth and cardiac muscles are also present in
blood vessels and heart respectively.
• Smooth and cardiac muscles are involuntary in nature. Skeletal
and cardiac muscles are sometimes referred as striated muscles
due to their specific microscopic appearance.
4. Skeletal Muscle and Associated
Connective Tissue
• The basic unit of a muscle is fibre.
• It is a multinucleated cylindrical cell bounded by an outer
membrane called the sarcolemma.
5. Skeletal Muscle and Associated
Connective Tissue
• Connective tissue is
important in the texture and
edibility of meat e.g fibrous
protein, collagen, reticulin
and elastin.
• Each muscle is surrounded
by a sheath of connective
tissue known as epimysium.
6. Skeletal Muscle and Associated
Connective Tissue
• From the inner surface of
epimysium, a septum of
connective tissue penetrates
into muscle and surrounds
the bundles of muscle fibres
or fasciculi.
• This connective tissue is
called perimysium. It
contains major blood vessels
and nerves.
• Each muscle fibre is
surrounded by a connective
tissue layer called
endomysium, beneath which
is delicate sarcolemma or
muscle cell membrane.
8. Skeletal Muscle and Associated
Connective Tissue
• Fish muscle is tender because of less connective tissue.
Individual muscle fibres are composed of myofibrils which are
10-20nm thick and are the basic units of muscular contraction.
In fish the fibres are arranged between the sheaths of
connective tissue and are much shorter than in other meats.
• The connective tissue is present as short transverse tissue
called mycommata dividing the long fish muscle into segments
called myotomes.
9. Skeletal Muscle and Associated
Connective Tissue
• The individual myofibril are separated by a fine network of
tubules called Sarcoplasmic Reticulum (SR), this reticulum is
a highly specialized mash of tubes concerned with calcium ion
(Ca 2+) control and hence the initiation and arrest of muscle
contraction.
• The myofibrils are bathed in a liquid matrix called sarcoplasm
which contains, mitochondria, enzymes, glycogen, ADP,
myoglobin and creatine.
11. MECHANISM OF MUSCULAR
CONTRACTION
• Contraction and relaxation of striated muscle occurs by the
sliding action of the thick filaments over the thin filament,
with the length remaining the same.
• Proteins responsible for muscular contraction are myosin
(thick filament) and actin (major protein in the thin filament).
• Actin: major protein in the thin filament. It is bound to the
muscle structure much more firmly than myosin.
• Troponin and tropomyosin proteins also regulate muscle
contractions.
12. MECHANISM OF MUSCULAR
CONTRACTION
• Ca2+ are released from the vesicle of the Sarcoplamic Reticulum in the fibrils,
following a stimulus received by the muscle fibre , initiated by the CNS. Calcium
stimulates myosin ATPase thus releasing the energy necessary for muscle
contraction to facilitate the sliding action of actin filament which forms contractile
acto-myosin.
• Calcium regulates actin-myosin interaction by directly binding to the Troponin-C
component of the I filament. Troponin is a myofibrilar protein associated with the
thin filament. It controls the interaction between actin and myosin.
• It is attached to tropomyosin another myofibril protein. Troponin is composed of
Troponin C, Troponin T and Troponin I. troponin C binds to calcium when the
muscle is stimulated thus facilitating the sliding effect of actin.
• Calcium interacts with troponin-tropomyosin component the globular head portion
with the myosin molecule interacts with actin by pulling the actin filaments parallel
to the fibre axis.
14. COMPOSITION OF MUSCLE
TISSUE
• Muscle tissue contains approximately 75% water and 25% solids, of which
19% are proteins. Lipids constitute about 2.5 to 5% of muscle.
• Water is the largest component comprising two third to three fourth of the
muscle tissue.
– Due to polar behavior, water molecules are attached with the electrically
charged groups of muscle proteins. About 40.5% of the total water in muscle is
so tightly bound that it is almost impossible to dislocate it. The attraction of
molecules keeps on decreasing as the distance from the reactive groups
increases. Thus, most of the water exists in immobilized and free forms. When
pH of meat is more than isoelectric point, the enhanced negative charge
increases the interfilamental space resulting in retention of excess water. It may
be noted that almost 70% of water content in fresh meat is located within the
myofibrils. Further, an increased water holding capacity is associated with
juiciness and tenderness of cooked meat.
15. COMPOSITION OF MUSCLE
TISSUE
• Muscle proteins have been broadly classified into three categories:
– Myofibrillar proteins -- soluble in dilute salt solution
– Sarcoplasmic proteins -- soluble in water or very dilute salt solution.
– Stroma or connective Tissue proteins-- almost insoluble
• Myofibrillar proteins:
– These proteins constitute contractile part of the muscle and make up
about 60% of the total protein in the skeletal muscle.
– Myofibrilar proteins are of special interest to the technologists because
they contribute to approximately 95% of the water holding capacity,
75% of the emulsifying capacity and to a large extent the tenderness of
meat.
16. COMPOSITION OF MUSCLE
TISSUE
• Sarcoplasmic proteins: make up about 30-35% of the total proteins in the
skeletal muscle.
– Myoglobin is a conjugated protein consisting of a prosthetic heme moiety and a protein moiety
(globin). It provides red colour to the muscle and serves as a carrier of oxygen to the muscle fibre. It is
the most important pigment of meat colour. Cytochrome enzyme, flavin etc. contribute very little to
meat colour.
• Stroma or connective tissue proteins:
• The connective tissue is composed of an amorphous ground substance or
matrix in which formed elements mostly fibres and a few cells are embedded.
The ground substance is a viscous glycoprotein solution.
• The extracellular connective fibres are:
a. Collagen
b. Reticulin
c. Elastin
17. COMPOSITION OF MUSCLE
TISSUE
• Collagen is the main fibrous protein the muscles and
significantly influence the meat toughness. It makes upto 40-
60% of the total stroma protein and 20-25% of the total protein
in the body. A fine network of collagen fibres is present in
almost all tissues and organs including skeletal muscles. It is
the most common constituent of tendons.
• Lipids
– Lipid is a major component of the carcass of a meat animal. It is highly
variable and is inversely proportional to the moisture content.
18. COMPOSITION OF MUSCLE
TISSUE
• Carbohydrates
– Immediately after slaughter, muscle normally contains a very small amount (nearly 1%) of
glycogen. It is a macromolecule of glucose residues which serves as a reserve polysaccharide
of animal tissue. However, it gets worked up before the completion of rigo mortis and plays a
key role in attaining the ultimate muscle pH. Both the rate and amount of glycolysis influence
the colour, tenderness and water holding capacity of meat.
• Minerals
– About 3.5% of the total body weight is inorganic matter. Most of the total body inorganic
material is located in skeletal tissue primarily as salts of calcium and phosphorus and some
other minerals especially magnesium. In living meat animal, essential minerals like calcium,
phosphorus, sodium, potassium, sulphur, chlorine, magnesium, iron etc. and trace elements like
manganese, copper, iodine, zinc, cobalt etc. Serve a variety of important functions. These
functions may be physical, chemical or biological depending on the chemical form and the
location in body tissues and fluids.
19. COMPOSITION OF MUSCLE
TISSUE
• In the conversion of muscle to meat, inorganic elements play an important role.
Their main function relates to development of rigor mortis and alteration of fluid
balance which cause a drop in pH and water holding capacity. Inorganic
constituents also influence the meat colour and tenderization. Several inorganic ions
act as catalysts during oxidation of meat fat, enhancing the process of rancidity
development.
• Vitamins
– The vitamin content of meat is variable, depending on the species and age of the animal, the
degree of fatness and type of feed received by the animal.Water-soluble vitamins are localized
in lean tissues whereas fat-soluble vitamins in fatty tissues. Variety meats have substantial
amounts of B-complex vitamins. Pork contains 5-10 times more thiamine content as compared
to mutton. The exudates from cut meat surfaces and drip loss during thawing of frozen meat
contain an appreciable amount of B-complex vitamins and amino acids. Most of the vitamins in
meat are relatively stable during processing or cooking. However, thiamine or to some extent
vitamin B6 are susceptible to heat treatment.
21. Preslaughter Care, Handling and
Transport of Meat Animals.
• It is not enough to produce healthy meat animals,
it is equally important to ensure that these animals
reach the point of slaughter in sound condition.
• Preslaughter care and handling can markedly
influence the quality and quantity of meat.
• Excited, stressed, bruised and injured animals are
not expected to yield wholesome meat.
22. Preslaughter Care, Handling and
Transport of Meat Animals.
• The underlying principles for preslaughter,
care, handling and transport of meat animals
are:
– 1. To avoid unnecessary suffering of animals
during transport.
– 2. To ensure minimum hygienic standards
– 3. To prevent spread of diseases.
23. TRANSPORT OF MEAT ANIMALS
• Driving on Hoof
– Animals reared within 6-10 k.m from the point of slaughter can be driven on foot. This distance can
be covered in 4 to 5 hours. This mode is especially suitable for animals accustomed to pasture
grazing. It allows them to browse on indigenous grass or shrubs and take water en route. So the
animals suffer minimum weight loss or shrinkage due to travel.
–
• Transport by Road Truck
– Distance up to 500 km or 12-15 hours journey may be negotiated by road truck. Such vehicles should
have non-slip floor. It is also important to provide temporary or permanent protective overhead
coverings, making provision for adequate ventilation. Proper partitions should separate unequal sized
animals or different species. If the journey is required to be continued after 12 hours, the animals
should be unloaded and offered enough feed and water. Transportation by road trucks allows
convenience of loading and unloading at the appropriate places.
24. TRANSPORT OF MEAT ANIMALS
• Transport by Rail Road
– For distances over 500 km, it is advisable to transport animals by
railways. It is economic on maintenance and easy to handle. Besides,
there is a saving on extortions and other incidental expenses. Animals
should be provided as lib water and feed at least for an hour before the
journey commences. It will be beneficial if water troughs are provided
within the roofed rail wagons. Railway wagons meant for this purpose
should have a non-slip floor and a free flow of air. . In fact, shrinkage
losses may come down to as low as 5 percent.
• Transport by sea: Ships are used only for international transport.
• Transport by Air. : It is very rare and used only for highly
expensive animals.
25. EFFECT OF TRANSPORT ON
MEAT ANIMALS
• 1. Stress and fatiguei:
– These conditions are inevitable sequel to transportation and do
have a bearing on meat quality. These conditions may at times
lead to shipping fever and transient to tany. Shipping fever
develops due topasteurella and requires proper treatment,
otherwise virus may act as secondary invader and aggravate the
condition.
• 2. Loss of weight or shrinkage:
– Shrinkage takes place due to dehydration (Loss of water) and
depletion of muscle glycogen during the period of journey. In
general, it ranges from 3 to 10 percent depending on the
conditions and duration of transport.
26. EFFECT OF TRANSPORT ON
MEAT ANIMALS
• 3. Bruises, torn skin and broken bones Brushes are
noticed in most of the species due to transportation.
– The instances are particularly high in sheep and pigs.
Muscular bleeding may occur especially in pigs.
• 4. Death it may occur during long transportation.
– Sheep and pigs are particularly susceptible if animals of
unequal age and size are loaded in road trucks without
partitions due to suffocation. Sheep and goats couldalso die
in long distance transportation by ship due to non-
inflammatorydiarrhea.
•
27. CONVERSION OF MUSCLE TO
MEAT AND EDIBLE FLESH
• Conversion of muscle to meat actually starts when someone decides to sell
and market their pigs because this is when ante-mortem stress occurs with
the marketing and handling of animals.
• The physical and chemical changes occurring in muscle after an animal
dies are very important parts of the conversion of muscle into meat.
• The combination of the timing and occurrence of early post-mortem events
and the process known as rigor mortis (muscle stiffening) have tremendous
impact upon many meat properties important to processors and consumers.
• Knowledge of the nature, the extent, and the rate of the changes occurring
in muscle the first few hours post-mortem is needed to understand meat's
WHC, emulsifying capacities, color, tenderness, juiciness, firmness, and
susceptibility to bacterial growth.
28. CONVERSION OF MUSCLE TO
MEAT AND EDIBLE FLESH
• The reactions that take place from the killing of an animal or fish to
the time of consumption can be divided into 3
• (1).Pre-Rigor Stage or post-mortem glycolysis:
– This is when glycogen is converted to lactic acid resulting in a fall in
pH as lactic acid accumulates; the rate and extend varies with species
and differs with muscle.
– Well fed rested animals have large glycogen reserves therefore have a
lower pH in the post mortem state compared to meat produced from
animals exhausted at the of slaughter.
– For postmortem glycolysis to occur inorganic phosphate (Pi) must be
available to enable phophorylase to convert glycogen to glucose-1-
phosphate which is the first product of glycolysis. The energy is
derived from ATP and can be resythesised using creatine phosphate
(CP).
29. CONVERSION OF MUSCLE TO
MEAT AND EDIBLE FLESH
• (ii) Rigormortis:
– Refers to the development of the stiff and rigid condition in
muscles .
– It occurs when CP levels fall making it impossible for the muscle
to regenerate ATP. Therefore ATP levels fall and ultimately
diminish.
– The pH then falls and muscles lose elasticity thus become stuff
or stiff. Stiffening occurs because ATP prevents the myofibril
proteins actin and myosin from cross-linking to form the
extensible actiomyosin.
– Therefore ATP results in the formation actiomyosin. Rigormortis
occurs 12 hours after slaughter and may last 15-20hours in
mammals and 1-7 hours in fish. Rigormortis leads to muscle
shortening which is similar to contraction which results in
developing of tension in the muscle.
30. CONVERSION OF MUSCLE TO
MEAT AND EDIBLE FLESH
• (iii) Post rigor Stage:
– Time when the meat and the fish muscles gradually tenderize becoming
organically acceptable as aging progresses. Mammalian meat becomes
acceptable two-three weeks at 2oC following the dissolution of rigor. In
fish Rigormortis is important as it affords a stiffness to the fish
considered a sign of good quality by consumers.
• The phenomenon of rigor mortis resembles that of muscle
contraction in a living animal muscle except that rigor mortis
is irreversible under normal conditions. The resolution of rigor
mortis takes place due to microbial degradation of muscle
structure in due course of time.
•
31. CONVERSION OF MUSCLE TO
MEAT AND EDIBLE FLESH
• Apart from the conversion of muscle to meat other
changes that occur during this stage are
– Destruction of the antibacterial defense mechanism thus
encouraging growth of microorganism (reason why meat
spoils)
– As pH falls enzymes (Cathepsins) are released from the
lysosomes and degrade the tissue.
– There is accumulation of compounds modify the intrinsic
flavor associated with meat.
33. 1) ANIMAL TYPE:
• (1a)Animal species exhibit the following differences
– Myoglobin concentration in the muscle , this causes the meat to
be darker or lighter
– Flavor volatiles are specific for different (beef smells like beef,
pork like pork). Flavour volatiles are believed to reside in the fat.
– Ruminants tend to hydrogenate unsaturated dietary fat resulting
in more saturated fat than in non-ruminants.
– Difference in enzyme activity lead to variation in fate of post-
mortem glycolysis (PMG) and to the stability of post-rigor color
and texture
– Different textures in meat indicate differences in connective
tissue.
•
34. 1) ANIMAL TYPE:
• b) Breed:
– Breeds of the same species may account for differences in
– (i) Variation in myoglobin concentration of the same
muscle.
– ii) Differences in variation in intramuscular fat
– iii) Rates of post-mortem glycolysis
• c) Sex:
– Males have less intramuscular fat than females while
castrated animals have more fat than either males or
females. Considering flavor entire males produce meat of
undesirable odour/flavor.
35. 1) ANIMAL TYPE:
• d) Age
– Concentration of intramuscular fat increases with age & the
degree of unsaturation tends to decrease with age. Increase in
concentration of myoglobin leads to darker meat in older
animals. The older the animal the meatier the taste due to
increase of concentration flavor volatiles. An increase in
intermolecular cross links in older animals leads to increased
toughness.
• e) Anatomical location
– Concentration of connective tissue varies with muscles, hence
the variation in texture from the same animal, Colour intensity is
determined by myoglobin concentration. Enzyme constitution
varies and therefore any post mortem changes involving
enzymes will occur at different rates.
36. 1) ANIMAL TYPE:
• f) Regular exercise
– Frequent exercise will alter the constitution of muscle e.g
increased myoglobin concentration leads to darker meat
and increased glycogen stores lead to lower pH in the
muscles.
• g) Nutrition
– Intramuscular fat is more in well fed animals and such
animals have less moisture levels in the muscle whilst
undernourished have significant amount of moisture. Use
of feed additives may affect the flavor of pork.
37. 2. PRESLAUGHTER HANDLING
• Pre-slaughter environment can impose various stresses to the
animals.
• Stresses that result in high temperature and low pH encourage
protein denaturation with a loss of water holding capacity (WHC)
and colour making meat, pale, soft, and exudative (PSE). After rigor
and thus is observed in pork.
• The PSE is also attributed to sarcolemma destruction. At high pH
the WHC of muscles is maximal resulting in a dry relatively
compact structure which reflects little light while at normal pH the
decreased WHC of the fibres leads to a more open structure
associated with free water, capable of reflecting more light.
38. 2. PRESLAUGHTER HANDLING
• Stress resistant animals that survive the fatigue, exercise,
fasting etc can only undergo limited post-mortem glycolysis
resulting in a high pH which gives rise to dark firm meat
which is unpopular with consumers and is hygienically
undesirable since the environment is more favourable for
bacterial growth.
• Oxygen utilizing enzymes in the tissue are more active than at
low pH. Therefore oxygen cannot penetrate tissues causing
myoglobin to develop.
• PSE meat is most affected due to the increased loss of water
holding capacity associated with protein denaturation.
39. 3. PRE-RIGOR PROCESSING
• If muscle contract after death and Rigormortis occurs while the
muscle is in this state, changes which affect the quality of meat
may develop.
• If meat is frozen pre-rigor and rapidly thawed massive
shortening occurs accompanied by loss of fluid or drip.
• Therefore meat is usually left on the carcass until rigor is
complete or hot boning processes can be employed where
temperature is maintained at 10-15 oC, chilling is also delayed
and this calls for high standards of hygiene.
40. 3. PRE-RIGOR PROCESSING
Cont’d
• Such pre-rigor meat has good emulsifying and water holding
properties and is used in sausage and ham.
• Electrical stimulation has also been employed to accelerate
rigor and to allow rapid chilling to be done without shortening
the muscles.
41. 4. POST RIGOR TREATMENT
(Ageing)
• This ageing treatment gives rise to chemical changes that
result in meat tenderness.
• Ageing is not only necessary to improve tenderness but may
also result in undesirable colour changes like development of
met-myoglobin.
• During the storage, bacteria may proliferate and enzymes or
raw meat continue to act on the meat components forming
potential flavor precursors which maybe desirable or
undesirable.
• Lipid oxidation may also occur during air storage leading to
development of undesirable flavour compounds (esp Pork).
42. Pale, Soft and Exudative (PSE)
• In some animals, muscle pH drops rapidly below 5.80 during
the first hour after exsanguination to the ultimate pH while
muscle temperature is above 36oC.
• This kind of meat is termed Pale, Soft and Exudative (PSE).
The low pH prevents or retards microbial growth. The rate of
pH change post mortem also influences meat quality.
43. Pale, Soft and Exudative (PSE)
• Combination of high temperature and development of a low
pH (acid) in muscle causes denaturisation of muscle proteins.
This denaturisation causes:
– loss of protein solubility
– loss of water- and protein-binding capacity
– loss in intensity of muscle pigment colouration.
• It is the sarcoplasmic protein that is denatured and become
firmly attached to the surface of the myofilaments causing the
lightening of meat color. Loss of water binding capacity leads
to exudation.
44. Pale, Soft and Exudative (PSE)
• The gene that is responsible for PSE meat is the Halothane
sensitivity gene (HAL), which is associated with a fast rate of
post-mortem decline in pH and which is more likely in stress-
susceptible animals.
• Halothane positive animals are homozygous, and they can be
detected by exposure to halothane gas, which induces the
Porcine Stress Syndrome (PSS).
• However, a more accurate identification of three genotypes is
now possible using a direct marker test (DNA Test) developed
after the identification of the gene (ryadonine receptor gene,
RYR1) and the discovery of the specific mutation.
45. Dark Firm Dry
• Animals that struggle and are fatigued prior to slaughter have
lower glycogen levels resulting in higher post-mortem pH
producing a dark dried and close textured meat that is much
more susceptible to microbial spoilage, this meat is referred to
as Dark, firm and dry (DFD) and present a quality problem
especially in beef.
46. Cold shortening
• Cold shortening is the result of cooling warm or hot
carcass meat too quickly after slaughter.
• Cold shortening is predominantly seen in beef as well
as lamb if the internal temperature of the meat reaches
(or drops below) 14 °C, whilst the pH value is still
around 6.0 – 6.2 at this stage during rigor mortis.
• A temperature of around 14 °C is normally achieved
only after 12-16 h in cattle after slaughter and, in pork,
a temperature below 15 °C should not be attained
within 4-5 h after slaughter.
47. Cold shortening
• The combination of high pH value and low temperature
present at the same time in muscle tissue damages the SPR and
contraction, as well as relaxation, of the muscle fibres post
mortem cannot be controlled properly any longer.
• When damaged in this way, the SPR does not reabsorb the
Ca2+ ions released for contraction and a permanent high
concentration of Ca2+ ions, together with the non-activation of
the enzyme actin-myosin ATP-ase due to the damaged SPR,
causes the muscle fibres to contract heavily.
48. Cold shortening
• All energy obtained in an anaerobic way post-slaughter is
utilized for muscle contraction only and a large number of
cross-links between actin and myosin are established.
• As a result, meat is always tough and the solubility of the
protein is greatly reduced as well, as solubility correlates with
the numbers of cross-links within muscle tissue.
49. Cold shortening
• Cold shortening does not occur at, or below, a pH value of 6.0
and, once such a pH value is obtained, the carcass can be
chilled more rapidly but, as stated above, temperatures in
muscle tissue below 7 °C at this point must be avoided.
• Another way to avoid cold shortening is the 10-10 rule,
meaning that the temperature within meat on a carcass should
not be below 10 °C within 10 h after slaughter.
• This rule of thumb applies to carcass meat with bone in. When
meat is deboned in a hot stage of processing, the boneless meat
should not be chilled below 16 °C within 10 h.
50. Cold shortening
• Red muscles are more susceptible to cold shortening than
white muscles because white muscles demonstrate a more
sophisticated and developed SPR, which is responsible for the
release of Ca2+ ions.
• The SPR of white meat can reabsorb Ca2+ ions more
effectively than that of red meat and the impact from the
damaged SPR in white meat is not as strong as in red meat.
51. Post Mortem Glycolysis
• When oxygen supply to the muscle is depleted glycogen
undergoes anaerobic glycolysis to lactic acid.
• The level of glycogen in fish is much lower following the
excessive struggling normally associated with capture of fish
resulting in depletion of glycogen level.
• Postmortem degradation of glycogen in fish muscle occurs in
2 possible pathways i.e
– Hydrolytic or amylolytic
– Phosphorolytic pathway
• Hydrolytic pathway dominates in fish whilst in mammals
phosphorolytic pathway is responsible for degradation
53. Post Mortem Glycolysis
• Initial breakdown of glycogen may differ but the final
pathway glycolysis is the same for either animal or fish
muscle.
• Rate of postmortem glycolysis in muscle is affected by
– temperature,
– muscle fibre type,
– hormonal secretions
– and intensity of nervous stimuli.
• Depletion of glycogen stores in fish results in a high pH
at rigor (around 7.0) giving rise to alkaline rigor.
54. Post mortem pH
• Lactic acid production causes a drop in pH from 7.2-7.4 to
5.3-5.5 this fall retards the growth of spoilage bacteria and
impacts a more acceptable meat color.
• A higher pH is desirable in frozen fish to prevent toughness.
The netfall of ATP is related to onset of rigor mortis.
55. ELECTRICAL STIMUMULATION
• Electrical stimulation (ES) of carcass muscles soon after
slaughter accelerates their normal decline in pH and may
enhance tenderization during conditioning.
• Although there was some early work on ES in the US,
commercial possibilities did not become apparent until it was
shown in New Zealand that stimulation prevented COLD
Shortening in lamb.
• ES now is widely used for BEEF and LAMB. There are some
who consider it can be used for pork, although care must be
taken to prevent PSE.
56. ELECTRICAL STIMUMULATION
• As well as protecting against cold shortening, electrical
stimulation may improve
– meat tenderness,
– color and appearance, and
– subjective scores for youthfulness.
• However, cooking losses may be increased by ES.
57. ELECTRICAL STIMUMULATION
• Apart from guarding against cold shortening, the beneficial
effects of ES on meat tenderness could also involve muscle
fiber fracture. In other words, when the muscle contracts
violently after slaughter it may rip up the muscle fibers making
them more tender.
• ES is ineffective on dark-cutting beef and post mortem muscle
stimulation is of no value without an accelerated decline in pH.
In other words, dark-cutters have little or no glycogen after
slaughter, so they cannot make much lactic acid, so they
cannot benefit from advanced glycolysis
58. ELECTRICAL STIMUMULATION
• ES is ineffective on dark-cutting beef and post mortem
muscle stimulation is of no value without an
accelerated decline in pH.
• In other words, dark-cutters have little or no glycogen
after slaughter, so they cannot make much lactic acid,
so they cannot benefit from advanced glycolysis
• ES may enhance the activation of lysosomal cathepsins
while the carcass is still warm. In other words, ES may
turn on some of the enzymes that make meat more
tender during the conditioning period.
59. ELECTRICAL STIMUMULATION
• Different voltages have been used: from 32 to
1600 V.
• Different amperages have been used: from 0.5 to
6 A.
• Types of electrode have included
– aluminum foil
– probe or pin types
– rectal probes
– multipoint electrodes
– hooks and shackles
61. MEAT TENDERNESS
• Meat tenderness is influenced by various
factors
– Sarcomere length
– Muscle fibre diameter
– Sarcomere fragmentation
– Collagen solubility
– Amount of marbling
– Distribution of marbling
62. MEAT TENDERNESS
Trait Tender Tough
Sarcomere length 3.6µm 1.8µm or less
Muscle fibre diameter 40µm 80µm
Sarcomere fragmentation 6 15
Collagen solubility 28% 6%
Amount of marbling 7% 2%
Distribution of marbling extensive collected
63. TENDERISATION
• To make meat more tender there is need to
– Make the sarcomere longer
– Disrupt the integrity of myofibrils
– Disrupt integrity of the connective tissue
64. Tenderising by ageing
• During ageing there is breakdown of some of tissues or long
molecular chains of protein into smaller simpler substances by
enzymes.
• Ageing produces a more uniformly tender product however
there is risk of microbial contamination during storage. The
color also deteriorates and there is weight loss.
• Meat can be aged as carcasses, quarters, sides and individual
cuts in an unwrapped condition, at specific temperatures, eg 6-
7 oC for 8 days with controlled relative humidity and adequate
air flow to maintain temperature.
65. Tenderising by ageing
• Can also be aged as small parts packed in heat shrinkage, gas
impermeable film, in this case the meat is boned out placed in
the bag, the bag is evacuated sealed and heat shrunk.
• The bagged meats are then placed fat surface upwards on racks
at temperature around 3 oC for 14 days.
• This method does not call for humidity control and there is no
weight loss however the method is costly and there is a
possibility of exudation making the meat unsightly.
66. Mechanism of Post Rigor
Tenderness
• Changes that take place during ageing are catalysed by 2 groups of
enzymes i.e calcium activated factor and lysosomal enzymes.
• The calcium activated factor is a calcium requiring endogenous
protein which is active at neutral pH in the presence of calcium ions.
It degrades troponin T, Z lines, connectin, M line proteins and
tropomyosin.
• Troponin T binds Troponin I and C to tropomyosin and the thin
filaments, therefore dissolution of Troponin T results in
fragmentation thus disrupting integrity of connectin (disruption) or
degradation of z lines causes sarcomeres to be longer and disrupt
integrity of myofibrils resulting in myofibril fragmentation.
67. Mechanism of Post Rigor
Tenderness
• Therefore Myofibril Fragmentation Index (MFI) can be used
to measure meat tenderness. Connectin or titin a major
component of gap filaments (G filaments) becomes weakened
following ageing.
• Weakening of this protein coupled with degradation of nebulin
(in rabbits and chicken) results in destabilisation of the G-
filaments
68. Lysosomal or Cathepsins
• Lysosomal or Cathepsins
• Cathepsin exhibits an optimum pH of 5.5 and are
active at 37 oC. They are released by lysosomes
under acidic conditions and upon completion of
glycolysis cathepsins hydrolyse myosin, α actin
and actin. Cathepsin-D in beef degrades Z-lines,
α-actinin, actin and desnin.
• Commercial used enzymes these include
69. Commercial used enzymes
• Enzymes derived from tropical plants e.g papain, bromelain
and ficin they act on the connective tissue fibre protein
therefore they will be suitable for cuts containing large
proportions of connective tissue.
• Those derived from animals like trypsin.
• Those derived from either bacteria of Fungi these act primarily
on the muscle fibres with little action on connective tissue
protein. Their activity is lost at temperature above 55oC
70. Commercial used enzymes
• Tenderization action of enzymes take place mainly over
cooking temperature range and no activity occurs at
refrigeration temperature.
• Enzymes preparation are standardised before they are used for
treating amount used depends on taste or products required.
71. Methods of applying exogenous
enzymes/injection method
• Addition of exogenous enzymes to raw meat can be done in
difference in different ways including injection into a live
animal prior to slaughter. When injected the animals
circulatory distributes enzymes throughout the carcass
therefore the muscle in the carcass contain same concentration
of enzymes however there is accumulation of enzymes in
certain organs e.g liver, kidney, tongue making them
disintegrate on cooling.
• Postmortem pre-rigor pumping of dressed carcasses this can be
done either by intravenous injections or intramuscular
injections using a series of needles were distribution is by
diffusion through the muscle.
72. Methods of applying exogenous
enzymes/injection method
• Convectional needle injection of cuts using single or
multineedle pumps, the larger the injection volume the faster
the distribution in the meat.
• Dipping this is an old-fashioned method which proved in-
effective for a carcass since it over tenderises the surface
producing a marshy texture. It is effective at household levels
where it can be used on small cuts which are initially forked
and immersed in enzyme solution for about 20 minutes.
73. Non Enzyme methods
• Stretching the sarcomere: carcasses are suspended and stretched
with the hind leg acting as a canti-lever or stretching rods and
clamps can be used as stretching devices when stretching is
mechanically done there is correlation between sarcomere length
and degree of tenderness.
• Blade or needle tenderizer: this method employs machines with
multiple blade and or needles that penetrate the meat as it passés
through a conveyor.
• Marinading: this involves soaking a cut of meat in a solution of
acetic acid or lactic acid and salt. The solution also impacts acidic
flavours that would be practical when flavour is compatible with
nature of end product.
74. Non Enzyme methods
• Pressure tenderisation: most effective in prerigor
meat where myofibrils are weakened using a
combined treatment of high pressure and heat
treatment (temperature used 45-60 oC).
• Electrical stimulation: reduces cold shortening
capacity leading to myofibril fragmentation. The
lower pH created enhances acid proteases.
75. Non Enzyme methods
• Cooking:
– As cooking progresses contractile proteins in meat become
tender. For cuts that are low in connective-tissue. “Dry
heat” methods like pan fry/barbequing. For cuts with high
amount of connective tissue, moist heat methods eg :
Braising are used .
• Carving:
– Meat should be carved at right angles to the length of
muscle fibre for maximum tenderness.
76. Non Enzyme methods
• Aging: Progressive Tenderization due to natural enzymatic
changes after Rigormortis due to enzymes like cathepsins
•
77. MEAT INSPECTION
• (1) Facilities construction and operational
sanitation
– Plants must be constructed so that they are clean and do not
contribute to hazards in meat.
– Operational sanitation -- specifications for water supply,
drainage, waste disposal, lighting, ventilation, refrigeration,
insect and rodent control; manpower: continuous inspection
patrol, reinspection privilege, surveillance of workers.
78. (2) Antemortem inspection
• Inspection of animals before slaughter, inspected in pens on the premises, on the
day of slaughter, in motion and at rest.
If acceptable, passed for slaughter If not, seriously crippled, reactors to T.B. test,
immature animals, minor epithelioma of the eye or orbital region.
• Condemned -- "downers", deads, moribund (about to die), comatose, temperature
above 105 F (106 F if swine), suspect dies in pen, animals with obvious symptoms
of a disease.
• Veterinary Medical Officer to condemn:
– All non-ambulatory disabled cattle; and
– All cattle showing central nervous system symptoms regardless of whether the cattle are
ambulatory.
• If not already dead, condemned livestock shall be killed by the establishment. Such
animals cannot enter establishments to be slaughtered or dressed
79. 3) Postmortem inspection
• Inspection after slaughter of head, viscera and carcass. Inspection proceeds
simultaneously with slaughter and dressing.
Causes for condemnation:
• Whole carcass: tuberculosis (generalized lesions), hog cholera, pneumonia,
abscesses, caseous lymphadenitis, epithelioma (involvement of parotid lymph if
ocular);
• Parts of carcass: abscesses, arthritis, bruises, contamination on the kill floor.
• Procedures for beef -- examine head: SPAM lymph nodes, masseters, tongue;
viscera: lungs, liver, heart, paunch, intestines, spleen; carcass: linings of thoracic,
abdominal and pelvic cavities, outside surfaces, palpate kidneys, AQL.
• AQL -- Acceptable Quality Level, statistical sampling plan to determine the
cleanliness of all carcasses processed.
• Final Inspected and Passed, Inspected and Condemned, Passed for Cooking, Passed
for Refrigeration
80. (4) Product inspection
• (a) Reinspection privilege
• To assure that a previously acceptable cut, carcass or product has not become sour,
rancid, tainted, spoiled or adulterated.
• (b) Inspection of imported meat products
• All meats are thoroughly inspected in the country of origin and representative
samples (determined statistically) are tested at the port of entry for cleanliness,
labelling, water content, wholesomeness, net weight, and fat percentage.
• (c) Processed products inspection
• Supervision of manufacturing procedures. Inspectors must be fully informed of
recipes, manufacturing processes to prevent adulteration, false labelling and to
assure sanitary handling.
• (d) Inspection of boneless manufacturing beef
• Statistically sample boneless manufacturing beef boxes.
81. (5) Laboratory determinations
and assays
• To determine specific levels of:
• Fat no more than 30% in frankfurters
• Water no more than 10% added water in bologna
• Curing agents no more than 120 ppm nitrite in cured bacon
• Phosphates no more than 0.5% in bacon
• Vegetable protein extenders no more than 3.5%, in frankfurters, of textured
vegetable protein
• Meat from other species no meat from other species in a product (detected by
antigen-antibody tests)
• Chemical residues specific tests to detect: hormones, insecticides, pesticides
82. (6) Control and restriction of
condemned products
• Once inspectors condemn an animal, a carcass, a cut
or a product, it must be identified as Condemned and
held under lock and key or in suitably marked
containers and disposed of by:
– Rendering -- for inedible fats, greases or oils
– Tanked -- made into animal feed or fertilizer
– Incinerated -- burned
– Chemically denatured -- kerosene, FD & C #3 green dye,
diesel, carbolic acid
– Frozen -- held at -10° F for five days and sold as animal
feed
83. (7) Marking, labelling and
application of inspection insignia
• Meat labels for prepared meat items
– Name of product
– Ingredients statement
– Quantity of contents
– Inspection legend
– Firm's name and address
• Special markings (qualifying phrases)
– "Keep Frozen"
– "Cereal Added"
– "Artificially Colored"
– "Artificial Smoke Flavor"
84. Ante-mortem Examination of
Meat Animals
• Ante mortem Examination of meat animals awaiting slaughter
is very necessary in order to produce to whole some meat and
thus safeguard the health of meat consumers.
• It should be conducted 12-24 hrs before slaughter by qualified
veterinarians in fairage pens.
•
• It should be ensured that animals are not subjected to any kind
of cruelty.
• All animals meant for slaughter should be rested at least for 24
hours and should not be fed for at least 12 hours before
slaughter but they should be provided with plenty of water.
85. Objectives
• 1. Detection of animals suffering from
scheduled infectious diseases which are
communicable to man.
• 2. To detect certain diseases which are
toxic or contagious and whose
identification is either difficult or
impossible during post mortem, e.g.
tetanus, rabies, farcy, listeriosis, septic
metritis, sturdy in sheep etc.
• 3. To prevent food poisoning out breaks
e.g. in salmonellosis carcass or organs
show little noticeable change on post
mortem
• 4. To make postmortem
examination more efficient,
accurate and less laborious.
• 5. To protect the health of
butchers and slaughter house
personnel.
• 6. To prevent unnecessary
contamination of building and
equipment of the abattoir.
• 7. To implement disease control
programme with more precision
by tracing back the source of
disease.
86. Ante-mortem Examination
procedure
• It should be carried out in two stages
• Stage I
• General examination : Meat animals
should be observed in the lairage pens
during rest as well as in motion. The
general behaviour, reflexes, fatigue,
excitement, gait, posture. Evidence of
cruelty, level of nutrition, symptoms
of diseases, or any other
abnormalities should be closely
observed.
• Stage II
• Detailed examination: Suspected
or diseased animals should be
segregated for detailed
examination.
• Their temperature, pulse rate and
respiration rate should be
recorded.
• Animals showing elevated
temperature and systematic
disturbance should be detailed for
further inspection and treatment in
the isolation pen.
87. Principles of judgement in
antemortem examination
• 1. Fit for slaughter- Animals which are normal and free from
any symptoms of disease should be sent for sacrifice
• 2. Unfit for slaughter- highly emaciated, skin bound animals
and those affected with tetanus or communicable diseases like
rabies etc. or diseases which can not be treated should be
declared unfit for slaughter.
88. Principles of judgement in
antemortem examination
• 3. Suspects- All suspected animals need further attention.
Some animals with localized condition and recovered cases
should be passed for slaughter as suspect with instructions
for careful postmortem examination.
– i.Detained animals Some animals need to be detained for
specified period of time for treatment of disease or excretion of
known toxic residence.
– ii. Emergency slaughter It is recommended in cases where the
animal is in acute pain or is suffering from a condition where
any delay in slaughter would be contrary to the welfare of
animal. It is done under strict supervision so that there is no
hazard to the consumer health.
90. Postmortem Inspection
• Many diseases and abnormal conditions not detectable on
Antemortem, necessitate a careful postmortem inspection.
• It should be conducted as soon as possible after carcass dressing is
complete, as setting of carcass may render it difficult to expose and
examine the lymphnodes afterwards.
• It has to be carried out in a hygienic manner avoiding unnecessary
cuts. However, character and extent of disease lesions whether
localized or general or whether condition is acute, sub-acute or
chronic ahs to be property determined.
• It will involve palpation of organs and tissues, incisions where
necessary and laboratory tests in certain conditions. All these aspects
ate taken into consideration before passing the final judgment.
91. Objectives
• i. To detect and eliminate abnormalities from the carcass and
organs including contamination, thus ensuring that only meat
fit for human consumption is passed for food.
• ii. To check the efficiency of slaughter and carcass dressing.
• iii. To diagnose disease conditions for control purpose.
• iv. To ensure that carcasses, parts or organs marked unfit for
human consumption are property disposed of or destroyed.
92. Facilities
• i. Inspection points should have sufficient and well distributed light of 540
lux or 50 foot candles.
• ii. Adequate hand washing units with supply of hot and cold running water,
liquid soap and towels.
• iii. Meat inspection knives.
• iv. Sterilizers for complete immersion of knives, saws, cleavers etc.
• v. Stamping ink – A solution containing 1 to 2% of fuchsine in acetic acid
is used as stamping ink for carcasses. Alternatively, it can be prepared
according to the following formula Methyl violet 35g. Cane sugar 450g.
Ethyl alcohol 1363 and water 1636 ml. Sugar is first dissolved in water and
methyl violet is added at the end. The stamp generally bears the head of
the animal.
93. General principles
• Postmortem inspection involves visual perception and palpation of
organs and tissues, incisions where necessary and laboratory tests
wherever confirmation is required. It should always proceed in a
systematic and hygienic manner.
• Examination of lymph nodes is of paramount importance in post-
mortem inspection, since these glands drain different parts of the
body, condition of the particular part drained by it.
• A meat inspector must have the knowledge of topography and
normal appearance of lymph-modes 9 colour shape, size etc 0 in a
particular animal. The size of a lymph node generally depends on
the area drained by it.
94. General principles
• A swelling or enlargement or discolouration of a lymph node
indicates s a pathological condition. Some lymphnodes, which
drain lymph from important muscles, are of special interest in
meat inspection and these are referred as ‘meat lymphnodes’.
• In buffalo and cattle these lymphnodes are prescapular,
axillary, prefemoral, ischiatic and popliteal whereas in pig,
these are prefer moral and popliteal.
• In postmortem inspection, lymphnodes are exposed and
examined by population for size and consistency and if
necessary, incised to observe colour and diction of lessons.
95. General principles
• As a thumb rule, viscera and head should remain identifiable with the
carcass until the inspection is completed. The carcass should not be
subjected to any mutilation.
• The final decision about the fitness of the carcass and offals must rest only
with the veterinarian. He should be armed with enough powers to stop the
slaughter and dressing operations and size the carcass, if there are sufficient
ground to do so.
96. Procedure
• Based on the postmortem examination, meat
inspector can given any of the four judgements.
– a. Passed.
– b. Total condemination
– c. Partial contamination
– d. Conditionally passed..
97. Procedure
In general, postmortem inspection of buffalo and swine
carcasses should proceed in the following order.
• Head
– An examination of surface of tongue is done for FMD and
other form of stomatitis. Palpation of tongue from dorsum
to lip is carried out to detect actinobacillosis.
98. Procedure
• Masseters are incised to examine for Cysticerus bovis. A detailed
examination of retropharyngeal, sub maxillary and parotid
lymphnodes becomes necessary to detect tuberculosis and
actinobacillosis.
• In case of pigs, the portions of muscles from tongue are examined
under microscope or trichinellosis and inspection of sub maxillary
lymph node is done as matter of routine.
• Viscera
All viscera should be inspected as they are removed from the carcass.
Every organ and associated lymphnodes are examined. In case of any
abnormal condition, the organ are incised not to contaminate other
organs or carcass parts.
99. Procedure
• Lungs: Visual inspection followed by palpation is carried out
for evidence of pleurisy, pneumonia, tuberculosis, fascioliasis
and hydrated cysis. Bronchial and, edoastinal lymphnodes
should be incised to detect tuberculosis.
• Heart: pericardium is opened and looked for tuberculosis
pericarditis. Heart is incised to detect petechial haemorrhages
or cysts
100. Procedure
• Liver: The surface and substance of liver is examined
for fatty changes, actinobacillosis, and abscesses,
parasitic infections like Cysticercus bovis, fasciolliasis,
hydatid cysts or larval stage of Oesophaostomum.
• Kidney: Renal lymphnodes and adrenal glands should
be anthrax, tuberculosis or presence of artifacts.
•
Spleen: The surface and substance of spleen is
inspected for anthrax, tuberculosis or presence of
artifacts.
101. Procedure
• Stomach and intestine: The serous surface of these organs
could indicate tuberculosis or action bacillosis while interior
part reticulum could show penetration of foreign body.
Mesenteric lymph node is incised as a routine to look for
tuberculosis.
• Urinary bladder: The outer and inner surfaces of urinary
bladder are observed for diseased condition.
• Uterus and ovaries: These are opened for examination of
septic conditions.
102. Procedure
• Udder: This is examined for septic mastitis or abscesses,
Suprammary lymphnodes are incised for evidence of abscesses
or tuberculosis.
• Testicles: the outer surface substance and superficial inguinal
lymphnodes are inspected.
• Carcass The carcass should be inspected for evidence of
bruising or haemorrhage of discoloration. Local or general
oedema (drops) swelling or other abnormally of bones, joints
ot musculature.
103. Procedure
• Age of bruise can be determined by using bilirubbin test.
Inspection of thoracie and abdominal walls should be done for
inflammation, abscesses or tuberculosis. Diaphragm should be
lifted and examined carefully for tuberculosis.
• After the carcass is spilt, cut surfaces of sternum, ribs,
vertebrate and spinal cord should be examined.
104. Procedure
• Incision should be made on each quarter in the musculature
near the shoulder joint and near the pelvic bone for detection
of cysts (Cysti circus bovis and Cysticircus cellulosae) .
• Simultaneously prescapular, popliteal and prefomoral, iliac
and supramanuatory lymphnodes and also observed and if
necessary, incised for inspection.
105. Slaughtering and Dressing of
Meat Animals
• Slaughtering means pulling the food animals to death and thereafter
preparing the carcasses for human consumption.
• The essentials in the slaughter of food animals are that it should not
cause unnecessary suffering to the animals and bleeding should be
as efficient as possible. Besides, it should be safe for the be the
handles also.
• There are two main types of slaughter methods.
– I. Scientific or Humane slaughter.
– II. Ritual slaughter
106. Slaughtering and Dressing of
Meat Animals
• Scientific or Humane Slaughter
• Such a slaughter avoids unnecessary pain and cruelty to the food
animal and ensure as complete bleeding as possible. It is also ensure
speed of operation and safety of the personnel.
• Stunning is a process employed to create a state of immobility or
unconsciousness at the time of slaughter to 1 minute. Immediately,
the animal is hostel and bloods the animal to death.
• In USA and European countries, stunning has been made mandatory
by legislation in abattoirs, excepting those where ritual slaughter is
followed.
108. i.Mechanical instruments
• Instruments such as captive bolt pistol percussion stunner or free bullet
cause damage to the brain so the animal immediately losses the
consciousness. Common for stunning cattle and sheep
• An explosive cartridge is used to drive a bolt in the frontal bone of the
animal causing immediate immobility by destruction of the cortex and
deeper parts of the brain. In pneumatic stunner bolt is activated under
pressure to cause concussion without penetrating the frontal bone.
• Use of free bullet pistol may become necessary for large bulls having
very thick skull. Application point of captive bolt pistol differs with
species. In adult cattle or if employed for buffalo, it should be
positioned in the meddle of the forehead where two lines drawn from
the medial can thus of each eve of to the base of opposite horm cross.
109. i.Mechanical instruments
• In horned goat and sheep, the pistol point is placed just behind
the ridge running between the collapsed followed by tonic
spasms and then movement of the hind legs Pithing is also
done some times in adult cattle after stunning with captive bolt
pistol.
• In this process a thin steel rod (approx 0.5 m) is inserted into
the hole made in the skull by the captive bolt pistol. It will
destroy the medulla oblongata and reflex muscular action will
not take place during sticking and initial dressing. Thus pithing
enables the slaughter man to proceed quickly and with safety.
110. ii. Electrical stunning
• It is conveniently employed in stunning of small ruminants, pigs
and poultry. The instruments Either apparatus with a pair of tongs
carries electrodes by which alternating current (AC) is passed
through brain.
• A high frequency current (250mA) of comparatively low voltage of
usually 75 volts is used for 10 seconds by way of application of
electrodes or tongs at the base of the ears on either side of the head.
• The electrodes are kept wet in a 20% saline solution to enable the
current to pass easily through hair and skin. It produces
instantaneous unconsciousness for about 30 seconds.
111. ii. Electrical stunning
• Bleeding is very much efficient and the power consumption
is extremely low. If the current remains low missed shock
may occur resulting in paralysis of the animal, although it
remains fully conscious.
• It affects the quality of meat besides compromising the
safety of the handler. On the other hand, too tough current
may cause splash.
• It refers to the appearance of pathetical haemorrhages
throughout the subcutaneous tissue in pigs. The capillaries
get ruptured due to excessive increase in blood pressure.
112. iii. Chemical stunning
• Carbon dioxide gas stunning is most suitable for pigs and is
followed in many European countries. Co2 is heavier than air and
can be contained in a tunnel. The gas blocks the nerve endings.
• Animal is exposed to 65% carbon dioxide concentration through
oval type to 65% carbon dioxide concentration through oval type
tunnel, dip lift system or revolving wheel for 45 seconds.
• On exposure to gas, pigs become anaesthetized that are then shacked
and bled.
• Bleeding is quiet efficient since carbon dioxide stimulates
respiration favouring blood circulation. However, it requires more
space and is not fast.
113. Sticking or Bleeding of the
Animal
It can be done by any of the two methods;
– i.After hoisting on the overhead rail, carotid arteries and jugular veins
and jugular veins of both the sides are severed across the throat region
caudal to the larynx.
– ii. On the flour skin is incised along the jugular furrow and carotid
artery and jugular vein of one aide are severed. The knife is then passed
to the chest severing the anterior aorta and anterior venacava.
– Sometimes, knife reaches too far in the chest puncturing the pleura and
the blood may be aspirated into the thoracic cavity. This blood adheres
to the parietal pleura especially the posterior edges of the ribs. This
contamination of lungs is called back bleeding or over sticking. It
requires to be washed immediately.
114. Ritual Slaughter
• Slaughter without prior stunning of food animals as per
religious rites are referred -as ritual slaughter. There are widely
practical in many countries. In India and far East, Practically
all the meat animals are slaughtered in conscious state
• Jewish method of Slaughter or Schechita. The regulations for
Jewish slaughter came into existence around 500 AD.
Consumption of pork was strictly prohibited for jews,
probably as a safeguard against tapeworm.
115. Jewish method of Slaughter
• a. Animals to be slaughtered should be active. Moribund
animals which lie quite and also do not get up even by striking
with a stick must not be slaughtered. A blow on perforation of
the membranes of the brain constituted a mutilation. Therefore,
this method envisages slaughter of animals without prior
stuning.
• b. The incision across the neck is made by single rapid thrust
of sharp knife which severs the skin, muscles, oesophagus,
trachea, carotid arteries and jugular veins. This incision should
be completed without pause, pressure, stabbing or tearing.
116. Jewish method of Slaughter
• c. The dressing of the carcases should expose the diaphragm
and allow manual examination of thoracic organ.
• d. The blood vessels must be removed before the retail sail
of meat is undertaken. It is for this reason that only
forequarters are normally eaten. Hindquarters containing lot
of butchers (Schochet) and are thus rarely eaten.
• e. Kosher meat must be sold and consumed within three
days of slaughter.Jewish slaughter (Schechita) is undertaken
by a Schochet (cutter) Carcass fitfor jewish consumption is
stamped with kosher seal on the brisket while unfit is
pronounced as terepha.
118. 1. ISLAMIC RULING:
TERMINOLOGY
• Halal mean lawful in Arabic, and used to describe objects
rather than an action. Normally when describing an action that
is allowed we would say it is obligatory (fard/wajib),
recommended (mandoub) or permissible (mubah).
• Haram means prohibited or unlawful, this term is both used
for objects as well as actions. When describing an action that
is not allowed we would say it is prohibited (haram) or
disliked (makrouh)
•
119. ISLAMIC RULING:
TERMINOLOGY
• Mashbooh : Any food or drink which one cannot determine if
it is Halal or Haram due to insufficient information, unreliable
evidence etc, is catagorised as Mashbooh. One example of a
Mashbooh product is Whey powder.
• Rennet is used in the manufacture of Whey Powder. Rennet
can be derived from animal rennet as well as non-animal
rennet. If it is derived from pigs or animals that are not
slaughtered in accordance with the Islamic law them it will be
Haram. If the source of rennet is not known then it will be
classified as Mashbooh.
120. THE ISLAMIC PRACTICE IS TO
SLAUGHTER THE ANIMAL
• According to the following Hadith, Muslims must not
consume anything which is Mashbooh.
• The practice of slaughtering in Islam has always been to apply
a sharp blade to the neck of the animal.
• "Verily Allah has prescribed proficiency in all things. Thus, if
you kill, kill well; and if you slaughter, slaughter well. Let each
one of you sharpen his blade and let him spare suffering to the
animal he slaughters." [Sahih Muslim] #5167
121. 2.WHAT ARE THE CONDITIONS
FOR HALAL SLAUGHTERING?
• There are six main conditions for Halal Slaughtering (dhabh), as follows:
• 1. The one that slaughters must be a Muslim
• 2. The one that slaughters must pray
• 3. The tool used to slaughter must be sharp
– The object used to slaughter the animal should be sharp and used swiftly. The
Messenger (saw) said “and if you slaughter, slaughter well. Let each one of you
sharpen his blade” pain. Thus the animal does not feel pain.
– The movements and withering that happen to the animal after the cut is made
are not due to pain, but due to the contraction and relaxation of the muscles
deficient in blood. The blood must be drained completely before the head is
removed. This purifies the meat by removing most of the blood
122. WHAT ARE THE CONDITIONS
FOR HALAL SLAUGHTERING?
• 4. The slaughtering must be merciful animal is being killed in
the name of Allah, but the words are not just for us; the animal
has the right to know that it has been slaughtered in the name
of Allah
• 5. The person slaughtering must mentioned the name of Allah
(swt)
• 6. Must ensure the blood is spilt from the animal
123. 3. OTHER POINTS RELATING TO
HALAL SLAUGHTERING
• As well as the fore mentioned conditions of
slaughtering, the following should also be considered.
– 1. The animal can be slaughtered by a woman
– 2. The slaughtering should take place in a slaughter house
– 3. The slaughter house must be free from contamination
– 4. Do not harm the animal
• It is Haram to harm the animal before slaughter using methods such
as stunning, striking it or giving it an electric shock
124. THE TYPES OF MEAT WHICH
ARE HARAM
• Animals that die naturally.
• The blood of the animal.‚
• The flesh of swine.
• Meat slaughtered in other than Allah name.
• Animal killed by strangling.
125. THE TYPES OF MEAT WHICH
ARE HARAM
• Animal killed by a blow.
• That which died by falling from a height.‚
• Animal gored or partially eaten – unless you can
slaughter it whilst it is still alive
• ‚
• Animals killed on a stone altar‚
• That you raffle by arrows
126. THE TYPES OF MEAT WHICH
ARE HARAM
• Donkey Meat
• Beast of Prey with Fangs
• Birds with Talons
• Carrion : (Carrion is the carcass of a dead animal
that becomes food for other scavenging animals.
This is haram (forbidden) to eat. )
127. 6.THE TYPES OF MEAT WHICH
ARE HALAL
– The Meat of Chicken
– The Meat of Rabbit
– The Meat of Horse
– The Meat of Fish
– It should be noted that the above lists of haram and
halal meat types are not an extensive list, but a
brief introduction to the categories.
128. 7.THE CONSEQUENCE OF NOT
EATING HALAL
– 1. Your Supplication (Dua’) may not be answered
Abu Hurairah narrated,
– 2. You will incur the wrath of Allah (swt) if you
slaughter in the name of others
– 3. If you agree with the Mushrik (idolaters) that
dead meat is halal, it will render you a Mushrik
130. Sources of Microbial
contamination of Meat
• There are a number of potential sources of contaminatin of
meat within the abattoir itself. These include:
– i. Hides/skin and feet
– ii. Gastrointestinal contents
– iii. Instruments such as knives, cleavers saws, hooks etc.
– iv. Water used for washing carcasses and instruments
– v. Airborne contamination
– vi. Hands and clothing of the personnel
• Contamination of meat may also take place during chilling,
ageing, processing, packaging and distribution.
131. Growth of Microorganisms in
Meat
The microorganisms that occur in meat may be bacteria or fungi.
• Fungi may be multi-cellular filaments (mold) or large single
cells with buds (yeast). Molds are capable of producing minute
spores under unfavourable conditions.
• Fungi gain upper hand over bacteria in meat when it is semi-
dry. Bacteria are unicellular microorganisms which are
spherical or ovoid or rod shaped and may occur in chains or
clusters.
• Bacterial growth or multiplication takes place in phases:
132. Growth of Microorganisms in
Meat
• Lag phase : Bacterial cells increase in size under
favourable Conditions
• Log phase : Bacterial cells multiply and increase in number
• Stationary phase : Growth rate becomes relatively constant
due to Environmental limitations
• Decline or death phase : There is destruction of bacterial
cells either Due to nutritional depletion or application of
Some preservation technique.
133. Growth of Microorganisms in
Meat
• An understanding of growth curve enables the meat
technologists to apply suitable preservation technique to
prolong the lag phase
• so that bacterial multiplication is retarded or if conditions have
already favoured some growth, then to hasten the death phase.
134. Growth of Microorganisms in
Meat
• Microbial growth activity in meat depends on various extrinsic
and intrinsic factors. The extrinsic factors are temperature,
oxygen and physical stage of meat. Different groups of
bacteria have their own growth optima.
• Psychrophiles have their optimum growth temperature below
200C, thermophiles above 450C and mesophiles an optima
ranging between these two.
135. Growth of Microorganisms in
Meat
• A refrigerated temperature of nearly 50C greatly retards the
growth of most psychrophilic organisms responsible for the
spoilage of meat.
• These bacteria generally belong to genera Pseudomonas,
Achromobactor, Flavobacterirum (G-rods), Micrococcus,
Streptococcus (G+rods), in cured or vacuum packed meat
products.
• The growth of bacteria on meat is usually characterized by
slime formation. It should be noted that total bacterial
population is above 107 when most signs of
136. Growth of Microorganisms in
Meat
• spoilage appeal on meat. Effective freezing
damages or kills most of the bacteria present on
meat. It may be remembered that meat spoilage
molds are also psychrophiles. On the countrary,
food pathogens generally belong to the
thermophilic group of bacteria.
• Oxygen environment around the mat will
determine the type of micro flora that will find
favourable conditions for growth.
137. Growth of Microorganisms in
Meat
• Bacteria found in meat may be either aerobic or anaerobic
or sometimes facultative. Bacteria that grow on the surface
of fresh meat are generally aerobes, whereas it is a different
flora in the interior of meat.
• All molds and yeast that grow in meat are aerobic in nature.
Use of different barrier packaging films restricts the activity
of aerobic microorganisms.
• Physical state of meat such as whole carcass or primal cuts
or retail cuts or comminuted form also influence the rate of
microbial growth. Microbial load increases with the
increase in exposed surface area of meat.
138. Growth of Microorganisms in
Meat
• Important intrinsic factors which affect the growth of
microorganisms in meat are water activity, pH and redox
potential.
• The amount of water available in a food system for the growth
of microorganisms is generally expressed in terms of water
activity. In fact, water activity (aw) is defined as vapour
pressure of the solution (p) in a food system divided by vapour
pressure of pure solvent or water (p0). Fresh meat generally
has a water activity of 0.99 or more.
139. Growth of Microorganisms in
Meat
• Most meat spoilage bacteria can grow only up to a water
activity of 0.91 but most spoilage mold and yeast can grow
upto a water activity of 0.86.
• This factor is commercially exploited in the production of
intermediate moisture meat products.
• Meat pH is yet another intrinsic factor which influences the
growth of microorganisms. Bacterial growth is best at neutral
pH (i.e.pH 7.0).
140. Growth of Microorganisms in
Meat
• It keeps on diminishing as meat pH goes down. If ultimate pH
is 6.0 or so, a large number of bacteria can still grow in meat.
• However, when normal ultimate pH of nearly 5.5 is achieved
in meat, bacterial growth is reduced to a large extent and the
growth of mold and yeast is favoured.
• Redox potential refers to the reducing or oxidizing conditions
prevailing in meat and this factor also influences the growth of
microorganisms.
141. Deteriorative Changes in Meat
• When meat depicts signs of decomposition and putrefaction, it is
referred as spoiled and becomes unfit for human consumption.
Besides microorganisms, intrinsic enzymes and insects also
contribute to eh spoilage of meat. Microbial spoilage of fresh chilled
meat is generally on the surface whereas it is within meat at higher
temperature. The causative agents and deteriorative changes are
quite different in aerobic and anaerobic spoilage.
• Under aerobic conditions, most significant symptom of meat
spoilage by bacteria and yeast is the slime formation on the surface
which results due to coalescence of a large number of individual
colonies. There may be discolouration of meat due to oxidizing
agents produced by bacteria or growth of colonies of coloured
organisms.
142. Deteriorative Changes in Meat
• The production of off-odours is also usually encountered. Bacterial
action causes proteolysis of meat proteins and lipolysis of meat
lipids. The end products of proteolysis are simple peptides and
amino acids under aerobic conditions whereas sulphur dioxide,
ammonia and other obnoxious compounds like amines and ketones
under anaerobic conditions. Residual carbohydrates yield skatol and
indole. Molds may grow on semi-dried meats causing surface
stickiness and whiskers.
• Under anaerobic conditions, meat decomposition is more offensive.
There may be putrefaction in the deep tissues such as lymphnodes
and bone joints, which is always accompanied by foul odours or
taints. Souring may also develop due to accumulation of organic
acids.
143. Identification of Meat Spoilage
• The identification of meat spoilage is based on the
deteriorative changes brought about by microorganisms,
intrinsic enzymes and insects.
• During spoilage process, several utilizable substrates are
consumed by microflora and new products are formed which
can be measured or determined in meat.
• Thus, meat spoilage can be detected by any of the following
physical and chemical methods:
144. Identification of Meat Spoilage
• i. Some physical observations such as discolouration, slime
formation, stickiness, whiskers etc. give a clear indication of spoiled
meats.
• ii. At low temperature, meat spoilage is accompanied by the
formation of many off-flavour compounds. Many of them owe their
origin to free amino acids and related substances.
• The production of H2S and mercaptans can be measured to ascertain
meat spoilage. Chemical determinations for the presence of
ammonia, indole, skatol, di-and trimethylamine etc. can be carried
out to detect microbial spoilage in meats.
145. Identification of Meat Spoilage
• iii. The extract release volume (ERV)
determination is particularly helpful in detecting
the incipient spoilage in meats.
– ERV refers to the volume of aqueous extract released
by a meat homogenate when it is passed through a
filter for a given period of time.
– As meats undergo microbial spoilage, there is a
complete hydrolysis of proteins which significantly
decrease the ERV.
146. Identification of Meat Spoilage
• iv. Dye (usually resazurin) reduction test is many
times used to detect spoilage in meats. Spoiled raw or
cooked meat homogenate prepared from stomacher
could bring about resazurin reduction within 2 hours.
This method shows a very good correlation with
bacterial numbers.
• v. Incipient spoilage in meat shows a simultaneous
rise in pH, bacterial counts and water holding capacity
of meat proteins. At the time of incipient spoilage, pH
value is more than 6.5 in ground meat but it may even
increase to 8.5 in putrid meats.
147. Identification of Meat Spoilage
• vi. High thoibarbituric acid and peroxide
values indicate chemical spoilage of meat and
meat products.
