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Meat science sits at the intersection of animal biology, public health, engineering, and food technology. This book has been developed to give students and practitioners a coherent, step-by-step understanding of how live animals become safe, high-quality meat—anchored in scientific principles and grounded in practical realities of modern slaughterhouses. We begin Chapter 1 by introducing meat animals and the scope of the sector, establishing terminology and the diversity of species and production systems. Chapter 2 builds the biological foundation with meat animal anatomy and the composition of meat, linking structure to function and, ultimately, to product quality. The transition from farm to abattoir is addressed holistically. Chapter 3 details slaughterhouse layout and essential facilities, emphasizing product flow, worker safety, and regulatory compliance.Chapter 4 explores transportation and handling, demonstrating how stress physiology and welfare outcomes translate directly into measurable meat quality traits. Pre- and post- aughter health safeguards are covered in Chapters 5 and 6, where ante-mortem and post-mortem examination procedures are presented as complementary pillars of food safety, disease control, and carcass judgment. The core technical operations are treated comprehensively in Chapter 7, outlining humane slaughtering methods, hygienic dressing, and critical control points. Because sustainability and value recovery are central to modern meat plants, Chapter 8 highlights the utilization of slaughterhouse by-products, turning potential waste into edible, pharmaceutical, and industrial resources.

Introduction Generally, muscles and offals obtained from animals feeding on grass and various other cultivated crops are regarded as meat. Apart from the meat obtained from the cattle, sheep, goat, pig and poultry, in many countries particularly Denmark, Belgium, Holland and Germany, horse meat is also consumed (hippophasia) as normal meat. Kangaroos are slaughtered for meat in Australia whereas capybara a large semi-aquatic vegetarian rodent, is used in South America as of one of the meat source. Dog meat (fragrant) is relished (Kinophasia) in few cultures such as South Korea, China, Vietnam and few north eastern states of India. In many parts of the world including Indian subcontinent, buffalo meat (Bubalus bubalis), also known as water buffalo or arna, is quite popular owing to its tenderness, leanness and low cholesterol qualities. It is distributed in many countries around the world such as India (largest population), Pakistan, China, Bangladesh, Indonesia, Philippines, Hungary, Italy and France etc. Bison (Bison bison) from North America is also called buffalo but they are separate species of the order Bovidae. Rabbits are also source of meat having higher growth rate and better feed conversion ratio (2:1). Elands are another meat source which are raised in Africa and Russia for meat purpose. Meat is quite high in protein content but the presence of saturated fat is perceived negatively due to its association in various cardiovascular diseases, diabetes etc. Efforts are made to produce lean meat having higher content of unsaturated fatty acids and to reduce the ω-6 to ω -3 fatty acids ratio.

• The proportion of bone varies depending on breed and body condition from 12 to 28% in the dressed carcase and approximately 15% in a good large ruminants carcase • Bone percentage increases with the age and weight of the animal and it is lowest in Aberdeen Angus cattle and it may increase to 28% in low quality large ruminants • The average bone % in bobby calves is 50%, veal calves 25%, in lamb 17–35%, in pork 12–20% and in poultry 8–17% Important parts of digestive system of meat animals Ox tongue • Filiform papillae found on the tongue are pointing backward and horny and thus, helps in food prehension • Actinobacillosis erodes the prominent posterior part of the tongue dorsum • 10–14 circumvallate papillae are spread in the region of prominent dorsum around the either side of the tongue midline • Black pigmentation of the tongue surface is fairly normal and not associated with any disease condition Sheep and goat tongue • Similar to cattle tongue • However, papillae are not horny but the centre of the tip is slightly grooved • Black pigmentation of the surface of the tongue is common in blackskinned sheep.

Facilities required for buffalo, sheep and goat slaughterhouses 1. Lairage 2. Large enough slaughterhouse area- • Separate area for pig slaughtering • Slaughter line and area for operations such as singeing, depilation, scraping should be demarcated by a high wall of at least 3 m high or by an open space of 5 m width 3. For stomachs and intestines emptying and cleaning, there should be one dedicated room 4. Separate rooms for handling guts and tripe 5. Fat and hides, hooves and horns should be stored in separate rooms 6. Accommodation for sick or suspected animals; detained meat or seized meat 7. Chilling/refrigeration room 8. Room for veterinary services 9. Provisions for lavatories, wash basins, changing rooms, and showers 10. Facilities for veterinary inspection 11. Entry and exit of slaughterhouse should have control mechanism 12. Separation of clean and unclean area 13. Waterproof flooring of room where meat is processed 14. Provision for steam exhaustion and sufficient ventilation 15. Sufficient artificial or natural lighting 16. Adequate potable water supply 17. Adequate hot potable water supply 18. Effluent treatment plant (ETP)

Introduction: Relation between transportation and meat quality One of the fundamental aims of animal production system is to ensure better quality meat. Apart from various animal husbandry practices that affect the meat quality, the transportation of meat animals from farm to slaughterhouse and their handling at lairage, affect the meat quality greatly. For better meat quality, the pH of the meat should fall from normal pH 7.0 - 7.2 in live animal to pH 5.5 (ultimate pH) after slaughter at the onset of rigor-mortis. The low muscle pH is required to inhibit the microbial growth and meat tenderization (cathepsins system is activated at low pH). The ultimate muscle pH is achieved through the accumulation of lactic acid which is produced as a result of anaerobic glycolysis of glycogen. After slaughter, as the oxygen supply to muscle ceases, ATP is generated through anaerobic glycolysis of glycogen and in this process lactic acid is produced. ATP is required to keep the muscle in relaxed stage. This anaerobic glycolysis carries on till the glycogen reserve is exhausted. So, higher the glycogen reserve at the time of slaughter, longer the length of time duration of anaerobic glycolysis and higher the quantity of lactic acid production and greater the reduction of muscle pH. Hence, livestock should be transported and handled before slaughter carefully because stress during transit and in lairage could severely deplete the glycogen reserve of livestock. The following facts should be especially taken care by the farmers raising livestocks for meat 1. Housing arrangement and design • Any flaws/deficiencies in design, layout, cubicle size and its design, drainage, water bowls, slats, air circulation, etc. should be rectified

Introduction • Meat inspection involves proper veterinary examination of live food animals prior to slaughter (called ante-mortem examination), inspection of carcases and offals and pathological examinations where deemed fit • Full ante-mortem inspection represents 50% of meat inspection • Ante-mortem inspection is particularly useful for detecting scheduled or infectious diseases which are communicable to man e.g. anthrax, rabies and glanders • Diseases where animals show nervous symptoms like tetanus, tuberculous meningitis, sturdy in sheep, lysteriosis, rabies, cysticosis etc. and where skin lesions are manifested such as food and mouth disease, swine fever etc. are easily detected during ante-mortem inspection which are difficult to be detected in post-mortem inspection • Animals must undergo veterinary ante-mortem inspection on the day of their arrival at the slaughterhouse or before the beginning of daily slaughtering The inspection must determine 1. Whether the animals are suffering from a disease which is communicableto man and to animals or whether they show symptoms 2. Whether they show symptoms of disease or of a disorder of their general condition which is likely to make their meat unfit for human consumption-- any medicine/substances 3. Whether they are tired, agitated or injured 4. Whether they are sufficiently clean to enter the normal slaughter protocol • For public health purposes, the veterinarian must separate normal animals from those which may be suffering from a potentially zoonotic disease or present a hygiene risk to the slaughter hall environment owing to the soiled condition of their hide/fleece

Post-mortem (PM) examination The core objective of post-mortem examination is to identify and eradicate defects and contaminations and thus, confirming that only meat suitable for ingestion are allowed to be passed Facilities for post-mortem inspection • Normal infrastructure amenities which delivers comfortable working environment and assist in presenting the carcases and its offals for PM examination • Every inspection place on the dressing over-head line must have lights of -- 540 lux (50 foot-candle) intensity light which does not alter the normal colours • Adequate facility for sanitising the hands, equipments and aprons should be provided • To sterilise the knives, cleavers and saws–a water bath operating at 82 ºC • Head, viscera and carcase are the three major inspection parts • On moving rails, viscera from a particular animal should move little ahead of its carcase so that any abnormality in viscera could be conveyed to the carcase examiner well in time • For precise recognition of carcases and its correlated viscera from an animal, the lines conveying the carcases and viscera should move in synchronized way • When a carcase is declared unfit for human consumption, all its the related parts such as head, viscera, blood and hide must be collected and disposed off • Every inspection point must have a easily accessible overhead rail line stop button

Introduction • Slaughtering of meat animals in way so as to effect minimum pain and suffering to animals is referred as humane slaughter • Slaughtering method followed should inflict least stress and suffering to the animals • There are acceptable and the unacceptable slaughtering methods and there is no ‘nice’ method to slaughter the food animals • In advanced countries, common slaughtering method consists of two steps, stunning and bleeding • Stunning is done to make animal unconscious and not to feel the pain during actual bleeding process which is followed next • Exception of stunning-- Jewish and Muslim methods of slaughter Stunning Humane slaughter consists of stunning followed by sticking (bleeding). Stunning is the process of making the animal unconscious till it is slaughtered so that the pain suffered during actual act of slaughtering can be alleviated

Fat • Utmost significant slaughterhouse byproduct is fat obtained from intestines, kidneys, channel and other offals • Edible ox fat is rendered and the obtained product is called premier jus (higher grade fat) which is differentiated into oleo oil and oleo stearin • If all edible ox fat is rendered, it is called dripping and it used for human consumption • Inedible fat is used for soap manufacturing • The highest value fat from pig is recovered from peritoneal lining (leaf fat), and the subsequent highest value recovered from back fat, mesentery and omentum • Sheep fat is separated into oleo oil and oleo stearin because of its strong flavour • Mutton fat is harder and its stearin content is more than ox or pig and therefore, it is applied on the top of meat paste glass jar as a protective layer Rendering of edible fat Three principal procedure of rendering of edible fat are: i. Wet rendering ii. Dry rendering iii. Continuous low-temperature rendering

Muscle structure • All muscles are composed of muscle fibres which are the structural unit of muscles • In turn, every single muscle fibre is made up of numerous smaller components called myofibrils • Functional unit of myofibril is sarcomere Connective tissues associated with muscle • Whole muscle is surrounded by a sheath of connective tissue called epimysium • Whole muscle is divided into muscle bundles by perimysium formed out of connective tissue septa originating from the interior surface of the epimysium separating the muscle fibres • The perimysium contains the blood vessels and nerves

Introduction • Arrival of the nerve stimulus at the motor end plate result in reversal of the polarization of the sarcolemmal surfaces and the muscle gets activated • This causes momentarily loss of potassium and sodium ions impermeability by the sarcolemma and Ca++ ions combined with calsequestrin in the sarcotubular system gets dissociated bringing Ca++ ion equilibrium with the sarcoplasm • The junctional foot protein (JFP) and the L-type calcium channel (LTC) are the two big protein complexes responsible for the calcium release mechanism (Fig. 10.1) • This leads to increase in level of Ca++ ion from nearly 0.10 mM to 10 mM • Thus, troponin C, the calcium-binding site of the troponin complex becomes saturated bringing a structural modification resulting in interaction of actin with the MgATP2- on the H-meromyosin heads of the myosin molecule as the troponin I, the inhibitory protein, no more inhibits this interaction • The interaction of actin with the MgATP2- intensely activate contractile ATP-ase near the bonding leading to break down of MgATP2- to MgADP– at a greater rate and liberating energy for inward (towards the sarcomere center) pulling of the actin filament • This leads to breaking of bond between actin and myosin and thus, the myofibrillar part involved in above mentioned activity gets contracted

Constituents of meat i. Water- 75% ii. Protein- 19% iii. Soluble and non-protein substances- 3.5% iv. Fat- 2.5% • The muscle fibre is important unit of muscular tissue consisting of a) Myofibrils- formed protein structures embedded in sarcoplasmic fluid b) Sarcoplasmic reticulum- a fine system of tubules c) Sarcolemma- a very thin membrane surrounding the myofibrils and around the exterior side of this membrane, the connective tissue is found • 19% of protein in the muscle is muscle fibre (Table 11.1) • α-alanine, glycine, glutamic acid and histidine are the major free amino acids present in the fresh muscle

Post-mortem glycolysis (anaerobic glycolysis) • Post-mortem glycolysis is the basic function of muscle • Irreversible anaerobic glycolysis starts after the animal has died and oxygen supply to the muscles is cut • The various biochemical steps that occur in living animals for the conversion of glycogen into lactic acid when the oxygen supply is insufficient, are basically similar in slaughtered animal also • After slaughter, during anaerobic glycolysis in normal animals (not in the animals that are exhausted, excited or excessively exercised just prior to slaughter), the glycogen reserve of the muscle decreases appreciably resulting in the lactic acid production which will proceed to a pH level at which the enzymes involved in glycolysis become inactivated • In classic mammalian muscles this pH will be near to 5.4–5.5 (called Ultimate pH) • Muscle having almost 600 mg glycogen/100 g muscle at the time of slaughter will reach this pH • A protein called glycogenin is responsible for starting the glycogenesis (glycogen synthesis) in muscle and it binds with eight glucose molecules to produce a glycosyl-protein (Fig. 12.1) • Glycosyl-protein is used as primer by the enzyme proglycogen synthase and thus, proglycogen is formed • This proglycogen is converted into bigger macromolecule by the macroglycogen synthase and its branching enzyme

Introduction Storage of fresh meat without microbiological degeneration at temperature more than freezing point of meat is known as ‘conditioning’ or ‘ageing’ and it is said to enhance tenderness and flavor of the meat Conditioning is also known as ageing or proteolysis of meat • In the initial 24–36 h after the slaughter, glycolysis is the prevailing reaction going on during post-mortem • The organization of the contractile proteins can only be conserved by the constant supply of ATP (energy source) • But ATP supply becomes scarce with the passage of time after death and denaturation of the proteins starts • Denaturation is a physical or intramolecular reorganization without involving hydrolysis of the bonds occurring between the various amino acids of the polypeptide proteins chains • Denaturation is characterized by heightened reactivity of different chemical groups, a modification in molecules shape or size, reduced solubility and lost biological reactivity in cases of enzymes or hormones • In the course of post-mortem conditioning, proteins are prone for denaturation due to lower pH than in-vivo, temperatures more than 25 °C or less than 0 °C, dehydration and higher non- hysiological salt levels • Connective tissue proteins such as collagen and elastin do not undergo denaturation during conditioning

Introduction • The main objective of food preservation is to avoid food spoilage • So, the underlying principle behind all the meat preservation technique is providing adverse conditions for the growth and survival of the harmful microbials and such adverse conditions may be provided in the from of heat, cold, high level of salt, increasing acidity or removal of water/ oxygen • Meat can be preserved by many techniques such as drying, heating, low temperature, curing, addition of chemicals or by application of irradiation and high pressure • Addition of chemical i.e. chemical preservation which is accomplished by smoking is generally done after salting and pickling of meat Physical changes in stored raw meat 1. Shrinkage 2. Sweating 3. Bloom loss

Physicochemical parameters of meat 1. Moisture, ash and fat content • Meat samples are dried at 105 °C for 24 h for determining the moisture content and for ash content analysis, samples are burned at 525 °C • Fat determination is done by acidic hydrolysis of the sample • Sample is boiled initially and then cooled and later, it is filtered, washed and dried • Thereafter, petroleum ether is used to extract the fat • Ether is evaporated and the remnant is dried and weighed 2. Protein content • Often, protein in meat sample is estimated using Kjeldahl method • The protein content is determined by multiplying the nitrogen content in the meat sample by an appropriate conversion factor • Strong acid is used to digest the meat sample and the released nitrogen is measured by proper titration technique • Then, the protein quantity of the sample is determined from the nitrogen concentration of the meat • Kjeldahl method does not determine the protein content in straightway manner; a conversion factor (F) is required to convert the nitrogen content to protein content • Usually, a conversion factor of 6.25 (corresponding to 0.16 g nitrogen/g of protein) is used for several food samples

Introduction • The source of contamination of meat plant is largely from the animals entering in the plant • Severely contaminated hide/skin are the major source of abattoir contamination • If proper hygiene of employees, equipments and clothing is not followed, then even after skinning 10,000 to 100,000 bacteria/ in2 can be detected • Blades of knives can carry 80,000 to 40 millions bacterial per blade & hands of meat operative can have 3x109 bacteria/g of scrapings • The chance of contamination of carcase is greater at the point of incision and minimum at the farthest point from the incision place ‘Scotoma effect’ or ‘factory-blindness’ • Persons working in any factory or abattoir on routine basis slowly and slowly becomes unaware (mentally ‘blind’) about any sub-standard hygiene or cleanliness problem existing in the surrounding • This effect is known as ‘scotoma’ or ‘factory-blindness’ • Effect can be powerful and the any visitors to that factory or abattoir will instantly notice that sub-standard hygiene or cleanliness problem neglected by the persons working there

Pollution emanating from industrial units has become a major problem globally and it is generally monitored by some government agencies. These agencies enforce various laws and regularly carry out checks at the industrial units. Same is true with regards to slaughterhouses or abattoirs. Pollution parameters are parameters against which the effluents coming out of the Effluent Treatment Plant (ETP) of slaughterhouse or any industrial entity is measured against. Effluent generated during various processes of the slaughterhouse is directed towards the ETP and it undergoes different processes to reduce the pollutants level in the effluent. Then, the effluent is tested against the pollution parameters and the effluent must have less than the maximum permissible level of the pollution parameters. The effluent must not have more than the permissible maximum level of the pollutants after coming out of ETP before being discharged into the municipal sewage system or some natural water bodies.  Pollution parameters are 1. Biochemical oxygen demand (BOD) 2. Chemical oxygen demand (COD) 3. Chloride (Cl) 4. Dry matter (DM) or total solids (TS) 5. Grease, fat and oil 6. pH 7. Total nitrogen (N) 8. Pathogenic bacteria