Ch.3: Meat

Chapter 3 of the book "On Food and Cooking: The Science and Lore of the Kitchen" by Harold McGee (1984) Eating Animals Controversies in Modern Meat Production The Structure and Qualities of Meat The Transformation of Muscle into Meat Cooking Fresh Meat: The Principles Cooking Fresh Meat: The Methods Offal, or Organ Meats Preserved Meats

368 flashcards · Other · by lakesare

Part of Public › Books › On Food and Cooking (Harold McGee) · 16 courses

1. [Meat] About when did our ancestors begin to eat meat?

   About 2 million years ago, when they began to scavenge animal carcasses. A changing African climate had reduced the vegetation. Before that, our primate ancestors ate almost only plant foods. Active hunting came much later, about 100,000 years ago.

2. [Meat] Why were animal flesh and bone marrow important in human evolution?

   They are richer in energy and protein than nearly any plant food, which helped feed a growing brain. Later, meat made it possible for humans to settle the cold parts of Europe and Asia, where for some months of the year there were few plant foods.

3. [Meat] Why have many people throughout history refused to eat meat?

   Eating meat requires killing animals that feel fear and pain. So meat is both the most prized food and the most widely avoided of the major foods.

4. [Meat] Why has meat become younger and leaner in recent decades?

   The industry's drive for efficiency, and consumers' worry about animal fat.

5. [Meat] What problem does today's young, lean meat give the cook?

   It more easily ends up dry and flavorless. Traditional cooking methods often have to be adjusted for it.

6. [Eating Animals] What is the difference between meats proper and organ meats?

   Meats proper are muscles, which move the animal; organ meats are the innards. Example: liver, kidneys and intestine are organ meats.

7. [Eating Animals] Why are most of our meats muscles?

   The defining feature of animals is the power to move, and muscles are what move them. The word "animal" comes from an Indo-European root meaning "to breathe".

8. [Eating Animals] What is a muscle made of, down to the level of proteins?

   Long thin cells (muscle fibers), packed with filaments of two proteins, actin and myosin. Fibers contain many fibrils, which are assemblies of actin and myosin filaments. This dense packing of protein is why meat is so rich in protein.

9. [Eating Animals] What happens inside a muscle fiber when it contracts?

   Its actin and myosin filaments slide past each other, then lock together. A nerve impulse starts the sliding, which shortens the cell; bonds between the filaments (cross-bridges) hold them in the shortened position. Rabbit muscle fibers under a light microscope: relaxed (top) and contracted (bottom).

10. [Eating Animals] Why do animals store their energy almost entirely as fat, while plants store starch?

    Fat holds about twice as many calories per gram as carbohydrate, so a mobile animal carries less weight for the same energy.

11. [Eating Animals] How much fat can some migratory birds put on before migrating?

    About 50% of their lean weight, within a few weeks. Example: such birds then fly 3,000 to 4,000 km from the northeastern United States to South America without feeding.

12. [Eating Animals] When and where did meat become a regular part of the human diet?

    About 9,000 years ago in the Middle East, when people began to keep domesticated animals. Goats and sheep were domesticated first (after the dog), then pigs, cattle and horses.

13. [Eating Animals] From the start of agriculture until the Industrial Revolution, why did most people eat very little meat?

    Land growing grain feeds far more people than land grazing animals. So meat was expensive, a luxury of the rulers; most people lived on cereal gruels and breads.

14. [Eating Animals] How many pounds of grain does it take to produce 1 pound of chicken, pork and beef?

    Chicken 2, pork 4, beef 8. The United States, with one fifteenth of the world's population, eats one third of the world's meat; this is affordable only because of a surplus of grain.

15. [Eating Animals] Which 19th-century invention let fresh beef, not only salted meat, be sold widely across the United States?

    The refrigerated railroad car (1870s). Before that, meat was preserved in barrels of salt; salt pork was as much a staple as bread.

16. [Eating Animals] What did the English word meat first mean?

    Solid food in general, as opposed to drink. It came to mean animal flesh only around 1300. The old sense survives in "the meat of a nut".

17. [Eating Animals] Why do English animals have Germanic names (ox, sheep, swine) but their meats French ones (beef, mutton, pork)?

    After 1066, French-speaking Norman nobles ate the meat, while English peasants raised the animals. Example: beef from French boeuf, veal from veau, mutton from mouton, pork from porc.

18. [Eating Animals] Why does raw meat stimulate our taste receptors much more strongly than plant foods do?

    Chewing breaks the fragile muscle cells, releasing salts, sugars, amino acids and nucleotides. Our taste buds detect all of these. Plant cells have tough walls that chewing breaks little, and keep their protein and starch in inert storage granules.

19. [Meat and Health] For early humans, which nutrients was wild meat the most concentrated natural source of?

    Protein and iron, and (with oily nuts) energy. It is also unsurpassed for several B vitamins.

20. [Meat and Health] What happened to human stature and health with the rise of agriculture, about 10,000 years ago?

    Stature, bone strength and dental health declined. Starchy grains, poorer in calcium, iron and protein, replaced meat and vegetables, and crowding increased infectious disease.

21. [Meat and Health] Why is a diet high in meat associated with more heart disease and cancer?

    Energy With little physical activity, meat's calories contribute to obesity. Saturated fat The saturated fats typical of meat raise blood cholesterol. Displacement Meat takes the place of vegetables and fruits, which help protect against heart disease and cancer. McGee: "It helped make us what we are, but now it can help unmake us."

22. [Meat and Health] Which three families of DNA-damaging chemicals can form when meat is prepared?

    Heterocyclic amines (HCAs) From high-temperature reactions of creatine and creatinine with amino acids. Polycyclic aromatic hydrocarbons (PAHs) From wood or fat heated until it burns. Nitrosamines From nitrite combining with nitrogen-containing groups of amino acids. All three cause cancers in laboratory animals and may raise the risk of cancer of the large intestine.

23. [Meat and Health] Where are heterocyclic amines (HCAs, DNA-damaging chemicals) formed in the greatest amounts?

    At the surface of meat cooked well done by grilling, broiling or frying. Roasting in the oven puts only modest amounts of HCAs on the meat itself; most of them end up in the drippings in the pan.

24. [Meat and Health] How can the formation of HCAs (DNA-damaging chemicals) in cooked meat be reduced?

    Acid marinades, gentle cooking, and aiming for rare or medium doneness. Vegetables, fruits and acidophilus bacteria appear to bind HCAs in the digestive tract.

25. [Meat and Health] How can the PAHs (polycyclic aromatic hydrocarbons) on grilled meat be minimized?

    Grill over coals, not flaming wood; avoid fat flare-ups; eat smoked meat rarely. PAHs form when organic matter such as wood or dripping fat starts to burn. Leaving the grill uncovered also helps.

26. [Meat and Health] Why is nitrite used in cured meats?

    It suppresses the bacterium that causes botulism. It has been used in salt-cured meats for millennia.

27. [Meat and Health] What is the health concern about the nitrite in cured meats?

    Nitrite can combine with amino acids to form nitrosamines, which damage DNA. This happens in the digestive system and in very hot frying pans. As of 2004 there was no clear evidence that the nitrite in cured meats raises cancer risk.

28. [Meat and Health] Why is it practically unavoidable that meat surfaces carry bacteria?

    Hides and guts carry many bacteria, which reach the meat during slaughter. Mechanized slaughter makes this worse: carcasses are handled less carefully, and one infected carcass more easily contaminates others.

29. [Meat and Health] Which two bacteria are the most prominent causes of serious meat-borne illness?

    Salmonella and E. coli.

30. [Meat and Health] Why is Salmonella especially common in U.S. poultry and eggs?

    Poultry by-products are fed back to the birds, and the birds are crowded closely. By-products such as feathers and viscera are recycled as feed in industrial poultry farming. Salmonella (over 2,000 types) is the leading microbial cause of serious food-borne illness in Europe and North America.

31. [Meat and Health] What illness does E. coli O157:H7 cause?

    Diarrhea with blood, and in some patients (children above all) kidney failure. In the U.S. about a third of diagnosed patients need hospital care, and about 5% die.

32. [Meat and Health] Through which food do people most often catch E. coli O157:H7?

    Ground beef. The strain is carried by cattle without harming them. Grinding spreads a small contaminated portion through the whole mass of meat.

33. [Meat and Health] To what temperature should the center of ground meat be heated to kill E. coli?

    155°F / 68°C

34. [Meat and Health] In which temperature range do Salmonella and other bacteria multiply fast?

    Between 40 and 140°F (5 and 60°C).

35. [Meat and Health] How long may meat stay between 40 and 140°F (5 and 60°C) before bacteria become a risk?

    No more than two hours. So dishes on a buffet stay hot, and leftovers go into the refrigerator quickly and are later reheated to at least 160°F / 70°C.

36. [Meat and Health] What causes trichinosis?

    Cysts of a small parasitic worm, eaten in undercooked meat. The worm is Trichinella spiralis (older name Trichina spiralis).

37. [Meat and Health] Why was trichinosis long associated with pork in the United States?

    Pigs were fed garbage that sometimes contained infected rodents. The U.S. banned uncooked garbage as pig feed in 1980; since then there are fewer than ten U.S. cases a year, mostly from bear, boar and walrus.

38. [Meat and Health] What meat temperature kills the trichinosis worm?

    137°F / 58°C (medium doneness); aim for 150°F / 65°C for a safety margin.

39. [Meat and Health] Besides cooking, how can trichinosis worms in meat be killed?

    By freezing for at least 20 days at 5°F / –15°C or colder.

40. [Meat and Health] What is BSE ("mad cow disease")?

    Bovine spongiform encephalopathy: a disease that slowly destroys the brains of cattle.

41. [Meat and Health] Why is the infectious agent of BSE ("mad cow disease") so worrying for cooks?

    It is a prion, a nonliving protein particle that cooking does not destroy. It appears to cause a similar fatal disease in people who eat infected beef.

42. [Meat and Health] How did BSE ("mad cow disease") probably originate?

    Cattle were fed by-products of sheep with scrapie, a prion brain disease of sheep. This happened in the early 1980s; the sheep prions are thought to have adapted to cattle. This was the leading explanation in 2004; the origin of BSE is still not fully settled.

43. [Meat and Health] What evidence links BSE ("mad cow disease") to a human disease?

    In the mid-1990s, young Britons died of a new brain disease caused by a prion close to the BSE prion. Ten died in 1995 and 1996, of a new variant of Creutzfeldt-Jakob disease. The known death toll is in the low hundreds; the overall risk from beef appears very small. Prions are thought to be concentrated in the brain, spinal cord and retina of cattle.

44. [Meat and Health] Which foods have some countries restricted as a precaution against BSE ("mad cow disease")?

    Meat from older cattle, brains, sweetbreads, spleen, intestines, and machine-recovered scraps from the head and spine. Older animals are more likely to carry BSE; sweetbreads, spleen and intestines contain immune-system tissue.

45. [Controversies in Modern Meat Production] What are the main criticisms of modern industrial meat production?

    Drugs Chemicals that manipulate the animals' metabolism, which may affect human health. Living conditions Animals kept in increasingly artificial and crowded conditions. Feed Reprocessed agricultural waste in the feed. Example: this contributed to BSE and to the persistence of Salmonella in chickens. Pollution Hundreds of thousands of animals in one facility pollute water, soil and air.

46. [Controversies in Modern Meat Production] Why have castrated males (steers, capons) long been preferred as meat animals?

    Without sex hormones they are calmer, and their bodies make more fat relative to muscle.

47. [Controversies in Modern Meat Production] Why are hormones such as estrogen and testosterone given to beef cattle?

    They produce leaner, more muscular cattle, faster and on less feed. The U.S., Canada, Australia and New Zealand allow six hormones. Lab studies find the residues at allowed levels minute and harmless.

48. [Controversies in Modern Meat Production] Where have hormone treatments of beef cattle been banned since 1989?

    In Europe. The ban followed Italian veal producers injecting the banned steroid DES, which reached baby food.

49. [Controversies in Modern Meat Production] Why do producers add antibiotics to animal feed?

    To control disease among crowded animals; the antibiotics also make the animals grow faster on less feed.

50. [Controversies in Modern Meat Production] What is the real risk of antibiotics in animal feed?

    The evolution of antibiotic-resistant bacteria (Campylobacter and Salmonella). Residues in the meat are minute. Resistant bacteria have caused illness in U.S. consumers; Europe and Japan restrict antibiotics in animals.

51. [The Structure and Qualities of Meat] What is lean meat made of, by weight?

    About 75% water, 20% protein, 3% fat.

52. [The Structure and Qualities of Meat] Which three kinds of tissue make up meat?

    Muscle fibers Long cells that contract and relax to cause movement; the main tissue. Connective tissue Binds the fibers together and to the bones they move. Fat tissue Groups of fat cells among the fibers and connective tissue, storing energy for the fibers. The proportions and arrangement of these three largely determine the texture, color and flavor of meat.

53. [The Structure and Qualities of Meat] How thick and how long is a single muscle fiber?

    0.01 to 0.1 mm thick (about a human hair), and up to the length of the whole muscle. Fibers are grouped in bundles, which are what we see and tease apart in well-cooked meat.

54. [The Structure and Qualities of Meat] What is the grain of meat?

    The direction in which the bundles of muscle fibers run.

55. [The Structure and Qualities of Meat] Why do we carve meat across the grain?

    Fiber bundles pull apart more easily than they break, so short cut fibers are easy to chew apart. A slice cut across the grain is then chewed along the grain.

56. [The Structure and Qualities of Meat] How do growth and exercise make an animal's meat tougher?

    Each muscle fiber thickens by gaining more contractile fibrils, and thicker fibers are harder to cut across. The number of fibers stays the same.

57. [The Structure and Qualities of Meat] How is connective tissue arranged in a muscle?

    In layers: around each fiber, around fiber bundles, around whole muscles, and as tendons to the bones. The layers around whole muscles are silver-white sheets. The more connective tissue in a piece of meat, the tougher it is. Stronger muscles need more and stronger connective tissue.

58. [The Structure and Qualities of Meat] What is elastin?

    A stretchy connective-tissue protein that cooking cannot soften. Its cross-links do not break on heating. Ligaments and the walls of blood vessels consist mainly of it; most muscle contains little of it.

59. [The Structure and Qualities of Meat] What is collagen?

    The main protein of connective tissue, about a third of all the protein in an animal's body. It is concentrated in skin, tendons and bones.

60. [The Structure and Qualities of Meat] What happens to collagen when it is heated in water?

    It partly dissolves into gelatin. So connective tissue gets softer with cooking. The name is Greek for "glue producing".

61. [The Structure and Qualities of Meat] How do muscle fibers and connective tissue differ in their response to cooking?

    Muscle fibers become denser, drier and tougher; connective tissue becomes softer as its collagen turns to gelatin.

62. [The Structure and Qualities of Meat] Why is cooked veal gelatinous and tender, but mature beef less so?

    Young collagen has few cross-links, so it turns into gelatin easily. With age and exercise the total amount of collagen declines, but the remaining collagen becomes more cross-linked and less soluble.

63. [The Structure and Qualities of Meat] In which three places do animals form fat tissue?

    Under the skin Insulation as well as energy store. In the body cavity Distinct deposits, often around the kidneys, intestine and heart. Within and between muscles In the connective tissue separating muscles and fiber bundles. Its white spots in the red muscle are called marbling.

64. [The Structure and Qualities of Meat] Why are shoulder and leg cuts tough but the tenderloin tender?

    Shoulders and legs work constantly and have much connective tissue; the tenderloin barely works. Shoulders and legs carry the animal when standing and walking, and include several muscles with their sheaths; the tenderloin is a single little-used back muscle. The rib, short loin and sirloin are the tenderest cuts; shoulder, arm and leg are best cooked an hour or more to turn collagen into gelatin.

65. [The Structure and Qualities of Meat] What fraction of the protein in chicken legs and in chicken breast is collagen?

    Legs 5–8%, breast 2%. Legs work more, so they need more connective tissue.

66. [The Structure and Qualities of Meat] In which three ways does fat make meat seem more tender?

    Interruption Fat cells break up and weaken the connective-tissue sheets and the mass of fibers. Melting Fat melts when heated instead of drying and stiffening like the fibers. Lubrication Fat helps fibers slide apart. Example: beef shoulder has more connective tissue than leg, but also more fat, so it makes more succulent dishes.

67. [The Structure and Qualities of Meat] What kinds of movement do white and red muscle fibers each serve?

    White: rapid, brief bursts of force. Red: slow, prolonged effort. Example: a startled pheasant takes off with its white breast muscles; it stands and walks with its red leg muscles.

68. [The Structure and Qualities of Meat] What fuel do white muscle fibers use?

    Glycogen, a carbohydrate stored inside the fiber.

69. [The Structure and Qualities of Meat] Why do white muscle fibers tire quickly?

    Lactic acid builds up when they outrun the blood's oxygen supply, and their glycogen store is small. So white fibers work best in short bursts with long rests, in which lactic acid is removed and glycogen replaced.

70. [The Structure and Qualities of Meat] What fuel do red muscle fibers mainly use?

    Fat, which they can burn only with oxygen. Both the fatty acids and the oxygen come from the blood; red fibers also hold their own fat droplets and the machinery to burn them.

71. [The Structure and Qualities of Meat] Why are red muscle fibers thin?

    So that oxygen and fatty acids from the blood can diffuse into them quickly.

72. [The Structure and Qualities of Meat] Which two kinds of protein make red muscle fibers red?

    Myoglobin, which stores oxygen, and cytochromes, which use oxygen to burn fat. Both contain iron. The more oxygen a fiber needs, the more of both it has. Myoglobin is a relative of hemoglobin, the red protein of blood.Example: young cattle and sheep muscle is about 0.3% myoglobin and fairly pale; whale muscle has 25 times as much and is nearly black.

73. [The Structure and Qualities of Meat] Which meats consist almost entirely of white muscle fibers?

    Frog and rabbit muscle, and chicken and turkey breast. These animals make quick, occasional movements. Chicken and turkey legs are on average half white, half red.

74. [The Structure and Qualities of Meat] Which muscles consist almost entirely of red muscle fibers?

    The cheek muscles of cud-chewing steers, and the breast muscles of ducks and pigeons. These muscles work almost constantly; the breasts of migratory birds must power hours of flight.

75. [The Structure and Qualities of Meat] What does a myoglobin molecule (the red pigment of muscle) consist of?

    A ring-shaped cage (the heme group) with an iron atom at its center, attached to a protein (globin). The iron atom holds the oxygen. Hemoglobin has the same heme group.

76. [The Structure and Qualities of Meat] Which three colors can myoglobin in raw meat have, and what state of the iron atom gives each?

    Red The iron holds a molecule of oxygen (oxymyoglobin). Purple The iron holds no oxygen, because enzymes in the cell have removed it (deoxymyoglobin). Brown Oxygen has taken an electron from the iron, which can then hold only a water molecule (metmyoglobin). Left: the heme group. Right: purple, red and brown states.

77. [The Structure and Qualities of Meat] Why is fresh red meat red on the surface but purple inside?

    At the surface, oxygen from the air binds to myoglobin; inside, enzymes use up the oxygen. Example: a cut surface of raw meat "blooms" red within minutes in air; vacuum-packed meat is purple until unwrapped.

78. [The Structure and Qualities of Meat] What makes myoglobin (the red pigment of meat) more likely to turn brown?

    High acidity, heat or salt, and a long time with little oxygen. Acidity, heat and salt destabilize the protein. Enzymes in active meat can give brown myoglobin back an electron, which makes it purple again.

79. [The Structure and Qualities of Meat] Meat flavor has two parts: general "meatiness" and the aroma typical of the species. Which tissue provides each?

    Meatiness: the muscle fibers. Species aroma: the fat tissue.

80. [The Structure and Qualities of Meat] Where does the "meaty" taste of meat come from?

    From the fibers' proteins and energy molecules, broken into small pieces by enzymes and heat. The pieces are amino acids, sugars, fatty acids, nucleotides and salts. They give sweet, sour, salty and savory tastes, and react with each other on heating to form hundreds of aroma compounds.

81. [The Structure and Qualities of Meat] Why does well-exercised, red-fibered muscle (chicken leg, beef) taste stronger than white muscle (chicken breast, veal)?

    Red fibers hold more fat to break down, and more iron, oxygen and enzymes that break it down. The fat is in droplets and fat-like membranes. About 200 years ago, Brillat-Savarin mocked gourmets claiming to taste "the leg upon which a sleeping pheasant rests his weight".

82. [The Structure and Qualities of Meat] Why do beef, lamb, pork and chicken taste different from each other, when their muscle fibers are much alike?

    Their fat differs: fat stores flavor compounds from the species, its feed and its gut microbes. Muscle fibers do the same job in every animal, so their machinery is much the same.

83. [The Structure and Qualities of Meat] Which unusual molecules in their fat give lamb and mutton their characteristic flavor?

    Branched-chain fatty acids and thymol, the aroma molecule of thyme. The liver makes the branched-chain fatty acids from a compound produced by microbes in the sheep's rumen (first stomach).

84. [The Structure and Qualities of Meat] What gives pork its "piggy" note and its "sweet" note?

    Piggy: fat-soluble products of gut microbes. Sweet: lactones, the molecules that also characterize coconut and peach.

85. [The Structure and Qualities of Meat] How does grass feeding change meat flavor compared to grain feeding?

    Grass-fed meat tastes stronger; the deep "beefy" flavor is more prominent in grain-fed beef. Grass supplies odorous substances, polyunsaturated fatty acids and chlorophyll, which rumen microbes turn into terpenes (relatives of herb aromas).

86. [The Structure and Qualities of Meat] Skatole, a compound that smells like manure on its own, contributes to the flavor of grass-fed meat.

    It also adds a barnyard note to lamb fed on alfalfa or clover, and to pork.

87. [The Structure and Qualities of Meat] Why is lamb generally more popular than mutton (meat of mature sheep)?

    The flavor stored in fat gets stronger as the animal ages.

88. [The Structure and Qualities of Meat] Why is meat a good source of iron?

    The body absorbs iron from meat more efficiently than iron from plants. Possibly the pigment proteins hold the iron so that indigestible plant compounds cannot bind it.

89. [The Structure and Qualities of Meat] Which meats contain the most iron?

    The red ones: the redder the meat, the more iron. Example: beef and lamb have 2 to 3 times as much iron as pork; dark pork shoulder has twice as much as the loin.

90. [The Structure and Qualities of Meat] What trade-off do exercise and age bring for meat quality?

    More flavor, but tougher meat: thicker fibers and more cross-linked collagen. McGee: "Life intensifies flavor, and modern meat animals are living less and less."

91. [The Structure and Qualities of Meat] What were the two traditional ways of obtaining meat, and what meat did each give?

    Rural style Animals kept for work, milk, eggs or wool, slaughtered when no longer productive: mature, tough, lean and flavorful meat, usually stewed. Urban style Animals raised only for meat, well fed, little exercised and slaughtered young: tender, mild, fatty meat, usually roasted. The rural style was by far the most common until the 19th century.

92. [The Structure and Qualities of Meat] What does the USDA beef grading system mainly measure?

    The amount of marbling fat within the muscles. It was introduced in 1927, pushed by breeders of fat, corn-fed cattle. Government studies soon found that heavy marbling guarantees neither tenderness nor flavor. Only the U.S., Japan and Korea make fat content a major quality criterion.

93. [The Structure and Qualities of Meat] Why is mass-produced meat pale and tender?

    Fast growth in confinement It favors white muscle fibers, so the meat is pale. Little exercise Fibers stay thin. Weak collagen With rapid growth, collagen is constantly rebuilt and forms few strong cross-links. Active enzymes Rapid growth means high levels of protein-breaking enzymes, which tenderize the meat during aging.

94. [The Structure and Qualities of Meat] Why does modern meat dry out so easily in cooking?

    It is young, so mild, and also lean, so it has little fat to keep it moist. Traditional young meat was fatty and traditional lean meat was old. From the early 1960s consumers turned to leaner meat, and the USDA lowered its marbling requirements in 1965 and 1975.

95. [The Structure and Qualities of Meat] How does a slow-grown French label rouge chicken compare with an industrial chicken as meat?

    Firmer and more flavorful, and it loses a third less moisture when cooked. It is also leaner and more muscular. Label rouge chickens are a slow-growing breed, fed mainly grain, with outdoor access, slaughtered at 80 days or more; a standard industrial chicken is slaughtered at 40 to 50 days.

96. [Meat Animals and Their Characteristics] From which wild animal do cattle descend?

    The aurochs, or wild ox (Bos primigenius), of the forests and plains of temperate Eurasia.

97. [Meat Animals and Their Characteristics] Why is beef relatively dark and flavorful?

    Cattle take about two years to reach adulthood, the longest of our meat animals.

98. [Meat Animals and Their Characteristics] What are steers and heifers?

    Steers: males castrated as calves. Heifers: females that have never calved.

99. [Meat Animals and Their Characteristics] How much fat do the U.S. beef grades Prime, Choice and Select contain?

    Prime 10–13%, Choice 4–10%, Select 2–4%. Ground beef ranges from 5 to 30% fat.

100. [Meat Animals and Their Characteristics] How much of the variation in tenderness, juiciness and flavor of cooked beef does marbling fat explain?

     No more than a third. Other factors: breed, exercise and feed, age, slaughter conditions, aging, storage. Beef from older animals has darker color and coarser fibers.