Meat

The Neolithic Revolution allowed the domestication of vertebrates, including chickens, sheep, goats, pigs, horses, and cattle, starting around 11,000 years ago.

In modern usage, meat primarily means skeletal muscle with its associated fat and connective tissue, but it can include offal, other edible organs such as liver and kidney.

[8] Modern agriculture employs techniques such as progeny testing to speed selective breeding, allowing the rapid acquisition of the qualities desired by meat producers.

[9] Animals not previously exploited for their meat are now being farmed, including mammals such as antelope, zebra, water buffalo and camel,[9] as well as non-mammals, such as crocodile, emu and ostrich.

[11] Genetic analysis continues to reveal the mechanisms that control numerous aspects of the endocrine system and, through it, meat growth and quality.

For instance, a recombinant bacterium has been developed which improves the digestion of grass in the rumen of cattle, and some features of muscle fibers have been genetically altered.

Depending on their size, body shape and insulation through tissue and fur, some animals have a relatively narrow zone of temperature tolerance and others (e.g. cattle) a broad one.

[13] In plant feed, environmental factors influence the availability of crucial nutrients or micronutrients, a lack or excess of which can cause a great many ailments.

Artificial insemination is now routinely used to produce animals of the best possible genetic quality, and the efficiency of this method is improved through the administration of hormones that synchronize the ovulation cycles within groups of females.

[20] The biochemical composition of meat varies in complex ways depending on the species, breed, sex, age, plane of nutrition, training and exercise of the animal, as well as on the anatomical location of the musculature involved.

[24] The two most abundant myofibrillar proteins, myosin and actin,[24] form the muscle's overall structure and enable it to deliver power, consuming ATP in the process.

[42] In particular, the muscles of stressed animals are low in water and glycogen, and their pH fails to attain acidic values, all of which results in poor meat quality.

[43] Stunning can be effected through asphyxiating the animals with carbon dioxide, shooting them with a gun or a captive bolt pistol, or shocking them with electric current.

[43] After exsanguination, the carcass is dressed; that is, the head, feet, hide (except hogs and some veal), excess fat, viscera and offal are removed, leaving only bones and edible muscle.

[43] Under hygienic conditions and without other treatment, meat can be stored at above its freezing point (−1.5 °C) for about six weeks without spoilage, during which time it undergoes an aging process that increases its tenderness and flavor.

[44] In muscles that enter rigor in a contracted position, actin and myosin filaments overlap and cross-bond, resulting in meat that becomes tough when cooked.

[44] Over time, muscle proteins denature in varying degree, with the exception of the collagen and elastin of connective tissue,[44] and rigor mortis resolves.

[47] When meat is industrially processed, additives are used to protect or modify its flavor or color, to improve its tenderness, juiciness or cohesiveness, or to aid with its preservation.

[79] Toxic compounds including heavy metals, mycotoxins, pesticide residues, dioxins, polychlorinated biphenyl can contaminate meat.

[95][96] Meat production and trade substantially increase risks for infectious diseases (zoonosis), including of pandemics, whether though contact with wild and farmed animals, or via husbandry's environmental impact.

They are so significant that according to University of Oxford researchers, "a vegan diet is probably the single biggest way to reduce your impact on planet Earth... far bigger than cutting down on your flights or buying an electric car".

[110] The livestock sector may be the largest source of water pollution (due to animal wastes, fertilizers, pesticides), and it contributes to emergence of antibiotic resistance.

It is a significant driver of biodiversity loss and ecosystems, as it causes deforestation,[111] ocean dead zones,[112] species extinction,[113][114] land degradation, pollution, overfishing and global warming.

[129] Deforestation from practices like slash-and-burn releases CO2 and removes the carbon sink of grown tropical forest ecosystems which substantially mitigate climate change.

[135] According to the Assessing the Environmental Impacts of Consumption and Production report produced by United Nations Environment Programme's (UNEP) international panel for sustainable resource management, a worldwide transition in the direction of a meat and dairy free diet is indispensable if adverse global climate change were to be prevented.

[136] A 2019 report in The Lancet recommended that global meat (and sugar) consumption be reduced by 50 percent to mitigate climate change.

[142][143] In November 2017, 15,364 world scientists signed a Warning to Humanity calling for a drastic reduction in per capita consumption of meat and "dietary shifts towards mostly plant-based foods".

[161] Pythagoras believed that humans and animals were equal and therefore disapproved of meat consumption, as did Plutarch, whereas Zeno and Epicurus were vegetarian but allowed meat-eating in their philosophy.

[161] Later philosophers examined the changing practices of eating meat in the modern age as part of a process of detachment from animals as living beings.

Sociological research, ranging from African tribal societies to contemporary barbecue, indicates that men are much more likely to participate in preparing meat than other food.