On Food And Cooking Part 15

Stewing fowl

Turkeys

10 10.

Industrial

French fermiere, fermiere, U.S. premium brands U.S. premium brands

French appellation controlee appellation controlee

Duck

80 80.

Goose

85 85.

Quail (wild)

75 75.

Squab

85 85.

Guinea hen

25 25.

Pheasant

35 35.

The Transformation of Muscle into Meat The first step in meat production is to raise a healthy animal. The second step is to transform the living animal into useful portions of its flesh. The ways in which this transformation occurs affect the quality of the meat, and can explain why the same cut of meat from the same store can be moist and tender one week and dry and tough the next. So it's useful to know what goes on in the slaughterhouse and packing plant.

Slaughter The Importance of Avoiding Stress By a fortunate coincidence, the methods of slaughter that result in good-quality meat are also the most humane. It has been recognized for centuries that stress just before an animal's death - whether physical work, hunger, duress in transport, fighting, or simple fear - has an adverse effect on meat quality. When an animal is killed, its muscle cells continue to live for some time and consume their energy supply (glycogen, an animal version of starch). In the process they acc.u.mulate lactic acid, which reduces enzyme activity, slows microbial spoilage, and causes some fluid loss, which makes the meat seem moist. Stress depletes the muscles of their energy supply before slaughter, so that after slaughter they acc.u.mulate less lactic acid and produce readily spoiled "dark, firm, dry" or "dark-cutting" meat, a condition first described in the 18th century. So it pays to treat animals well. In November 1979, the By a fortunate coincidence, the methods of slaughter that result in good-quality meat are also the most humane. It has been recognized for centuries that stress just before an animal's death - whether physical work, hunger, duress in transport, fighting, or simple fear - has an adverse effect on meat quality. When an animal is killed, its muscle cells continue to live for some time and consume their energy supply (glycogen, an animal version of starch). In the process they acc.u.mulate lactic acid, which reduces enzyme activity, slows microbial spoilage, and causes some fluid loss, which makes the meat seem moist. Stress depletes the muscles of their energy supply before slaughter, so that after slaughter they acc.u.mulate less lactic acid and produce readily spoiled "dark, firm, dry" or "dark-cutting" meat, a condition first described in the 18th century. So it pays to treat animals well. In November 1979, the New York Times New York Times reported that a Finnish slaughterhouse had evicted a group of young musicians from a nearby building because their practice sessions were resulting in dark-cutting meat. reported that a Finnish slaughterhouse had evicted a group of young musicians from a nearby building because their practice sessions were resulting in dark-cutting meat.

Procedures Meat animals are generally slaughtered as untraumatically as possible. Each animal is stunned, usually with a blow or electrical discharge to the head, and then is hung up by the legs. One or two of the major blood vessels in the neck are cut, and the animal bleeds to death while unconscious. As much blood as possible (about half) is removed to decrease the risk of spoilage. (Rarely, as in the French Rouen duck, blood is retained in the animal to deepen the meat's flavor and color.) After bleeding, cattle and lamb heads are removed, the hides stripped off, the carca.s.ses cut open, and the inner organs removed. Pig carca.s.ses remain intact until they have been scalded, sc.r.a.ped and singed to remove bristles; the head and innards are then removed, but the skin is left in place. Meat animals are generally slaughtered as untraumatically as possible. Each animal is stunned, usually with a blow or electrical discharge to the head, and then is hung up by the legs. One or two of the major blood vessels in the neck are cut, and the animal bleeds to death while unconscious. As much blood as possible (about half) is removed to decrease the risk of spoilage. (Rarely, as in the French Rouen duck, blood is retained in the animal to deepen the meat's flavor and color.) After bleeding, cattle and lamb heads are removed, the hides stripped off, the carca.s.ses cut open, and the inner organs removed. Pig carca.s.ses remain intact until they have been scalded, sc.r.a.ped and singed to remove bristles; the head and innards are then removed, but the skin is left in place.

Food Words: Game Game and and Venison VenisonThe word game game is Germanic in origin. Its original meaning in Old English was "amus.e.m.e.nt," "sport," and after some centuries was applied to hunted animals by people wealthy enough to consider hunting as entertainment. ( is Germanic in origin. Its original meaning in Old English was "amus.e.m.e.nt," "sport," and after some centuries was applied to hunted animals by people wealthy enough to consider hunting as entertainment. (Hunt originally meant "to seize.") The term originally meant "to seize.") The term venison venison comes from the Latin verb comes from the Latin verb venari, venari, "to hunt," but ultimately from an Indo-European root meaning "to desire, to strive for," which also gave us the words "to hunt," but ultimately from an Indo-European root meaning "to desire, to strive for," which also gave us the words win, wish, venerate, Venus, win, wish, venerate, Venus, and and venom venom (originally a love potion). It once meant all hunted animals, but now refers mainly to deer and antelope, both ruminants, like cattle and sheep, that can eat weeds and brush and thrive on poorer land than their domesticated relatives. (originally a love potion). It once meant all hunted animals, but now refers mainly to deer and antelope, both ruminants, like cattle and sheep, that can eat weeds and brush and thrive on poorer land than their domesticated relatives.

Chickens, turkeys, and other fowl must be plucked. The slaughtered birds are usually immersed in a bath of hot water to loosen the feathers, plucked by machine, and cooled in a cold-water bath or cold-air blast. Prolonged water-chilling can add a significant amount of water to the carca.s.s: U.S. regulations allow 512% of chicken weight to be absorbed water, or several ounces in a 4-pound bird. By contrast, air-chilling, which is standard in much of Europe and Scandinavia, actually removes water, so that the flesh becomes more concentrated and the skin will brown more readily.

Kosher and halal meats are processed according to Jewish and Muslim religious laws respectively, which among other things require a brief period of salting. These practices don't allow meat birds to be scalded before plucking, so their skin is often torn. The plucked carca.s.ses are then salted for 3060 minutes and briefly rinsed in cold water; like air-chilled birds, they absorb little if any extraneous moisture. Salting makes meat fats more p.r.o.ne to oxidation and the development of off flavors, so kosher and halal meats don't keep as long as conventionally processed meats.

Rigor Mortis The Importance of Timing, Posture, and Temperature For a brief period after the animal's death its muscles are relaxed, and if immediately cut and cooked will make especially tender meat. Soon, however, the muscles clench in the condition called For a brief period after the animal's death its muscles are relaxed, and if immediately cut and cooked will make especially tender meat. Soon, however, the muscles clench in the condition called rigor mortis rigor mortis ("stiffness of death"). If cooked in this state, they make very tough meat. Rigor sets in (after about 2.5 hours in the steer, 1 hour or less in lamb, pork, and chicken) when the muscle fibers run out of energy, their control systems fail and trigger a contracting movement of the protein filaments, and the filaments lock in place. Carca.s.ses are hung up in such a way that most of their muscles are stretched by gravity, so that the protein filaments can't contract and overlap very much; otherwise the filaments bunch up and bond very tightly and the meat becomes exceptionally tough. Eventually, protein-digesting enzymes within the muscle fibers begin to eat away the framework that holds the actin and myosin filaments in place. The filaments are still locked together, and the muscles cannot be stretched, but the overall muscle structure weakens, and the meat texture softens. This is the beginning of the aging process. It becomes noticeable after about a day in beef, after several hours in pork and chicken. ("stiffness of death"). If cooked in this state, they make very tough meat. Rigor sets in (after about 2.5 hours in the steer, 1 hour or less in lamb, pork, and chicken) when the muscle fibers run out of energy, their control systems fail and trigger a contracting movement of the protein filaments, and the filaments lock in place. Carca.s.ses are hung up in such a way that most of their muscles are stretched by gravity, so that the protein filaments can't contract and overlap very much; otherwise the filaments bunch up and bond very tightly and the meat becomes exceptionally tough. Eventually, protein-digesting enzymes within the muscle fibers begin to eat away the framework that holds the actin and myosin filaments in place. The filaments are still locked together, and the muscles cannot be stretched, but the overall muscle structure weakens, and the meat texture softens. This is the beginning of the aging process. It becomes noticeable after about a day in beef, after several hours in pork and chicken.

The inevitable toughening during rigor mortis can be worsened by poor temperature control, and may be the source of excessive toughness in retail meats.

Aging Like cheese and wine, meat benefits from a certain period of aging, or slow chemical change, during which it gets progressively more flavorful. Meat also becomes more tender. In the 19th century, beef and mutton joints would be kept at room temperature for days or weeks, until the outside was literally rotten. The French called this mortification, mortification, and the great chef Antonin Careme said that it should proceed "as far as possible." The modern taste is for somewhat less mortified fles.h.!.+ In fact most meat in the United States is aged only incidentally, during the few days it takes to be s.h.i.+pped from packing plant to market. This is enough for chicken, which benefits from a day or two of aging, and for pork and lamb, which benefit from a week. (The unsaturated fats of pork and poultry go rancid relatively quickly.) But the flavor and texture of beef keeps improving for up to a month, especially when whole, unwrapped sides are and the great chef Antonin Careme said that it should proceed "as far as possible." The modern taste is for somewhat less mortified fles.h.!.+ In fact most meat in the United States is aged only incidentally, during the few days it takes to be s.h.i.+pped from packing plant to market. This is enough for chicken, which benefits from a day or two of aging, and for pork and lamb, which benefit from a week. (The unsaturated fats of pork and poultry go rancid relatively quickly.) But the flavor and texture of beef keeps improving for up to a month, especially when whole, unwrapped sides are dry-aged dry-aged at 3438F/13C and at a relative humidity of 7080%. The cool temperature limits the growth of microbes, while the moderate humidity causes the meat to lose moisture gradually, and thus become denser and more concentrated. at 3438F/13C and at a relative humidity of 7080%. The cool temperature limits the growth of microbes, while the moderate humidity causes the meat to lose moisture gradually, and thus become denser and more concentrated.

Muscle Enzymes Generate Flavor... The aging of meat is mainly the work of the muscle enzymes. Once the animal is slaughtered and the control systems in its cells stop functioning, the enzymes begin attacking other cell molecules indiscriminately, turning large flavorless molecules into smaller, flavorful fragments. They break proteins into savory amino acids; glycogen into sweet glucose; the energy currency ATP into savory IMP (inosine monophosphate); fats and fat-like membrane molecules into aromatic fatty acids. All of these breakdown products contribute to the intensely meaty, nutty flavor of aged meat. During cooking, the same products also react with each other to form new molecules that enrich the aroma further. The aging of meat is mainly the work of the muscle enzymes. Once the animal is slaughtered and the control systems in its cells stop functioning, the enzymes begin attacking other cell molecules indiscriminately, turning large flavorless molecules into smaller, flavorful fragments. They break proteins into savory amino acids; glycogen into sweet glucose; the energy currency ATP into savory IMP (inosine monophosphate); fats and fat-like membrane molecules into aromatic fatty acids. All of these breakdown products contribute to the intensely meaty, nutty flavor of aged meat. During cooking, the same products also react with each other to form new molecules that enrich the aroma further.

...And Diminish Toughness Uncontrolled enzyme activity also tenderizes meat. Enzymes called Uncontrolled enzyme activity also tenderizes meat. Enzymes called calpains calpains mainly weaken the supporting proteins that hold the contracting filaments in place. Others called mainly weaken the supporting proteins that hold the contracting filaments in place. Others called cathepsins cathepsins break apart a variety of proteins, including the contracting filaments and the supporting molecules. The cathepsins also weaken the collagen in connective tissue, by breaking some of the strong cross-links between mature collagen fibers. This has two important effects: it causes more collagen to dissolve into gelatin during cooking, thus making the meat more tender and succulent; and it reduces the squeezing pressure that the connective tissue exerts during heating (p. 150), which means that the meat loses less moisture during cooking. break apart a variety of proteins, including the contracting filaments and the supporting molecules. The cathepsins also weaken the collagen in connective tissue, by breaking some of the strong cross-links between mature collagen fibers. This has two important effects: it causes more collagen to dissolve into gelatin during cooking, thus making the meat more tender and succulent; and it reduces the squeezing pressure that the connective tissue exerts during heating (p. 150), which means that the meat loses less moisture during cooking.

Enzyme activity depends on temperature. The calpains begin to denature and lose activity around 105F/40C, the cathepsins around 122F/50C. But below this critical range, the higher the temperature, the faster the enzymes work. Some accelerated "aging" can take place during cooking. If meat is quickly seared or blanched in boiling water to eliminate microbes on its surface, and then heated up slowly during the cooking - for example, by braising or roasting in a slow oven - then the aging enzymes within the meat can be very active for several hours before they denature. Large 50 lb/23 kg slow-roasted "steams.h.i.+p" rounds of beef spend 10 hours or more rising to 120130F/5055C, and come out more tender than small portions of the same cut cooked quickly.

Aging Meat in Plastic and in the Kitchen Despite the contribution that aging can make to meat quality, the modern meat industry generally avoids it, since it means tying up its a.s.sets in cold storage and losing about 20% of the meat's original weight to evaporation and laborious tr.i.m.m.i.n.g of the dried, rancid, sometimes moldy surface. Most meat is now butchered into retail cuts at the packing plant shortly after slaughter, wrapped in plastic, and s.h.i.+pped to market immediately, with an average of 4 to 10 days between slaughter and sale. Such meat is sometimes Despite the contribution that aging can make to meat quality, the modern meat industry generally avoids it, since it means tying up its a.s.sets in cold storage and losing about 20% of the meat's original weight to evaporation and laborious tr.i.m.m.i.n.g of the dried, rancid, sometimes moldy surface. Most meat is now butchered into retail cuts at the packing plant shortly after slaughter, wrapped in plastic, and s.h.i.+pped to market immediately, with an average of 4 to 10 days between slaughter and sale. Such meat is sometimes wet-aged, wet-aged, or kept in its plastic wrap for some days or weeks, where it's s.h.i.+elded from oxygen and retains moisture while its enzymes work. Wet-aged meat can develop some of the flavor and tenderness of dry-aged meat, but not the same concentration of flavor. or kept in its plastic wrap for some days or weeks, where it's s.h.i.+elded from oxygen and retains moisture while its enzymes work. Wet-aged meat can develop some of the flavor and tenderness of dry-aged meat, but not the same concentration of flavor.

Cooks can age meat in the kitchen. Simply buying meat several days before it's needed will mean some informal aging in the refrigerator, where it can be kept tightly wrapped, or uncovered to allow some evaporation and concentration. (Loose or no wrapping may cause dry spots, the absorption of undesirable odors, and the necessity of some tr.i.m.m.i.n.g; this works best with large roasts, not steaks and chops.) And as we've seen, slow cooking gives the aging enzymes a chance to do in a few hours what would otherwise take weeks.

Cutting and Packaging In the traditional butchering practice that prevailed until the late 20th century but is now rare, animal carca.s.ses are divided at the slaughterhouse into large pieces - halves or quarters - which are then delivered to retail butchers, who break them down into roasts, steaks, chops, and the other standard cuts. The meat might not be wrapped at all until sale, and then only loosely in "butcher's paper." Such meat is continuously exposed to the air, so it tends to be fully oxygenated and red, and it slowly dries out, which concentrates its flavor at the same time that it leaves some surface areas discolored and off-flavored and in need of tr.i.m.m.i.n.g.

The modern tendency in butchering is to break meat down into the retail cuts at the packing house, vacuum-wrap them in plastic precisely to avoid exposure to the air, and deliver these prepackaged cuts to the supermarket. Vacuum-packed meat has the economic advantage of a.s.sembly-line efficiency, and keeps for weeks (as much as 12 for beef, 6 to 8 for pork and lamb) without any weight loss due to drying or tr.i.m.m.i.n.g. Once repackaged, meat has a display-case life of a few days.

Carefully handled, well packaged meat will be firm to the touch, moist and even-colored in appearance, and mild and fresh in smell.

Meat Spoilage and Storage Fresh meat is an unstable food. Once a living muscle has been transformed into a piece of meat it begins to change, both chemically and biologically. The changes that we a.s.sociate with aging - the generation of flavor and tenderness by enzymes throughout the meat - are desirable. But the changes that take place at the meat surface are generally undesirable. Oxygen in the air and energetic rays of light generate off-flavors and dull color. And meat is a nouris.h.i.+ng food for microbes as well as for humans. Given the chance, bacteria will feast on meat surfaces and multiply. The result is both unappetizing and unsafe, since some microbial digesters of dead flesh can also poison or invade the living.

Meat Spoilage Fat Oxidation and Rancidity The most important chemical damage suffered by meats is the breakdown of their fats by both oxygen and light into small, odorous fragments that define the smell of The most important chemical damage suffered by meats is the breakdown of their fats by both oxygen and light into small, odorous fragments that define the smell of rancidity. rancidity. Rancid fat won't necessarily make us sick, but it's unpleasant, so its development limits how long we can age and store meat. Unsaturated fats are most susceptible to rancidity, which means that fish, poultry, and game birds go bad most quickly. Beef has the most saturated and stable of all meat fats, and keeps the longest. Rancid fat won't necessarily make us sick, but it's unpleasant, so its development limits how long we can age and store meat. Unsaturated fats are most susceptible to rancidity, which means that fish, poultry, and game birds go bad most quickly. Beef has the most saturated and stable of all meat fats, and keeps the longest.

Fat oxidation in meats can't be prevented, but it can be delayed by careful handling. Wrap raw meat tightly in oxygen-impermeable plastic wrap (saran, or polyvinylidene chloride; polyethylene is permeable), overwrap it with foil or paper to keep it in the dark, store it in the coldest corner of the refrigerator or freezer, and use it as soon as possible. When cooking with ground meat, grind the meat fresh, just before cooking, since dividing the meat into many small pieces exposes a very large surface area to the air. The development of rancidity in cooked meats can be delayed by minimizing the use of salt, which encourages fat oxidation, and by using ingredients with antioxidant activity: for example the Mediterranean herbs, especially rosemary (p. 395). Browning the meat surface in a hot pan also generates antioxidant molecules that can delay fat oxidation.

Spoilage by Bacteria and Molds The intact muscles of healthy livestock are generally free of microbes. The bacteria and molds that spoil meat are introduced during processing, usually from the animal's hide or the packing-plant machinery. Poultry and fish are especially p.r.o.ne to spoilage because they're sold with their skin intact, and many bacteria persist despite was.h.i.+ng. Most of these are harmless but unpleasant. Bacteria and molds break down cells at the meat surface and digest proteins and amino acids into molecules that smell fishy, skunky, and like rotten eggs. Spoiled meat smells more disgusting than other rotten foods exactly because it contains the proteins that generate these stinky compounds. The intact muscles of healthy livestock are generally free of microbes. The bacteria and molds that spoil meat are introduced during processing, usually from the animal's hide or the packing-plant machinery. Poultry and fish are especially p.r.o.ne to spoilage because they're sold with their skin intact, and many bacteria persist despite was.h.i.+ng. Most of these are harmless but unpleasant. Bacteria and molds break down cells at the meat surface and digest proteins and amino acids into molecules that smell fishy, skunky, and like rotten eggs. Spoiled meat smells more disgusting than other rotten foods exactly because it contains the proteins that generate these stinky compounds.

Refrigeration In the developed world, the most common domestic method for preserving meat is simply to keep it cool. Refrigeration has two great advantages: it requires little or no preparation time, and it leaves the meat relatively unchanged from its fresh state. Cooling meat extends its useful life because both bacteria and meat enzymes become less active as the temperature drops. Even so, spoilage does continue. Meats keep best at temperatures approaching or below the freezing point, 32F/0C.

Freezing Freezing greatly extends the storage life of meat and other foods because it halts all biological processes. Life requires liquid water, and freezing immobilizes the food's liquid water in solid crystals of ice. Well-frozen meat will keep for millennia, as has been demonstrated by the discovery of mammoth flesh frozen 15,000 years ago in the ice of northern Siberia. It's best to keep meat as cold as possible. The usual recommendation for home freezers is 0F/18C (many operate at 1015F/12 to 9C). Freezing greatly extends the storage life of meat and other foods because it halts all biological processes. Life requires liquid water, and freezing immobilizes the food's liquid water in solid crystals of ice. Well-frozen meat will keep for millennia, as has been demonstrated by the discovery of mammoth flesh frozen 15,000 years ago in the ice of northern Siberia. It's best to keep meat as cold as possible. The usual recommendation for home freezers is 0F/18C (many operate at 1015F/12 to 9C).

Freezing will preserve meat indefinitely from biological decay. However, it's a drastic physical treatment that inevitably causes damage to the muscle tissue, and therefore diminishes meat quality in several ways.

Cell Damage and Fluid Loss As raw meat freezes, the growing crystals protrude into the soft cell membranes and puncture them. When the meat is thawed, the ice crystals melt and unplug the holes they've made in the muscle cells, and the tissue as a whole readily leaks a fluid rich in salts, vitamins, proteins, and pigments. Then when the meat is cooked, it loses more fluid than usual (p. 150), and more readily ends up dry, dense, and tough. Cooked meat suffers less from freezing because its tissue has already been damaged and lost fluid when it was heated. As raw meat freezes, the growing crystals protrude into the soft cell membranes and puncture them. When the meat is thawed, the ice crystals melt and unplug the holes they've made in the muscle cells, and the tissue as a whole readily leaks a fluid rich in salts, vitamins, proteins, and pigments. Then when the meat is cooked, it loses more fluid than usual (p. 150), and more readily ends up dry, dense, and tough. Cooked meat suffers less from freezing because its tissue has already been damaged and lost fluid when it was heated.

Cell damage and fluid loss are minimized by freezing the meat as rapidly as possible and keeping it as cold as possible. The faster the meat moisture freezes, the smaller the crystals that it forms, and the less they protrude into the cell membranes; and the colder the meat is kept, the less enlargement of existing crystals will occur. Freezing can be accelerated by setting the freezer at its coldest temperature, dividing the meat into small pieces, and leaving it unwrapped until after it has solidified (wrapping acts as insulation and can double the freezing time).

Fat Oxidation and Rancidity In addition to inflicting physical damage, freezing causes chemical changes that limit the storage life of frozen meats. When ice crystals form and remove liquid water from the muscle fluids, the increasing concentration of salts and trace metals promotes the oxidation of unsaturated fats, and rancid flavors acc.u.mulate. This inexorable process means that quality declines noticeably for fresh fish and poultry after only a few months in the freezer, for pork after about six months, for lamb and veal after about nine months, and for beef after about a year. The flavors of ground meats, cured meats, and cooked meats deteriorate even faster. In addition to inflicting physical damage, freezing causes chemical changes that limit the storage life of frozen meats. When ice crystals form and remove liquid water from the muscle fluids, the increasing concentration of salts and trace metals promotes the oxidation of unsaturated fats, and rancid flavors acc.u.mulate. This inexorable process means that quality declines noticeably for fresh fish and poultry after only a few months in the freezer, for pork after about six months, for lamb and veal after about nine months, and for beef after about a year. The flavors of ground meats, cured meats, and cooked meats deteriorate even faster.

Freezer Burn A last side effect of freezing is A last side effect of freezing is freezer burn, freezer burn, that familiar brownish-white discoloration of the meat surface that develops after some weeks or months of storage. This is caused by water "sublimation" - the equivalent of evaporation at below-freezing temperatures - from ice crystals at the meat surface into the dry freezer air. The departure of the water leaves tiny cavities in the meat surface which scatter light and so appear white. The meat surface is now in effect a thin layer of freeze-dried meat where oxidation of fat and pigment is accelerated, so texture, flavor, and color all suffer. that familiar brownish-white discoloration of the meat surface that develops after some weeks or months of storage. This is caused by water "sublimation" - the equivalent of evaporation at below-freezing temperatures - from ice crystals at the meat surface into the dry freezer air. The departure of the water leaves tiny cavities in the meat surface which scatter light and so appear white. The meat surface is now in effect a thin layer of freeze-dried meat where oxidation of fat and pigment is accelerated, so texture, flavor, and color all suffer.

Freezer burn can be minimized by covering the meat as tightly as possible with water-impermeable plastic wrap.

Thawing Meats Frozen meats are usually thawed before cooking. The simplest method - leaving the meat on the kitchen counter - is neither safe nor efficient. The surface can rise to microbe-friendly temperatures long before the interior thaws, and air transfers heat to the meat very slowly, at about one-twentieth the rate that water does. A much faster and safer method is to immerse the wrapped meat in a bath of ice water, which keeps the surface safely cold, but still transfers heat into the meat efficiently. If the piece of meat is too large for a water bath, or isn't needed right away, then it's also safe to thaw it in the refrigerator. But cold air is an especially inefficient purveyor of warmth, so it can take days for a large roast to thaw. Frozen meats are usually thawed before cooking. The simplest method - leaving the meat on the kitchen counter - is neither safe nor efficient. The surface can rise to microbe-friendly temperatures long before the interior thaws, and air transfers heat to the meat very slowly, at about one-twentieth the rate that water does. A much faster and safer method is to immerse the wrapped meat in a bath of ice water, which keeps the surface safely cold, but still transfers heat into the meat efficiently. If the piece of meat is too large for a water bath, or isn't needed right away, then it's also safe to thaw it in the refrigerator. But cold air is an especially inefficient purveyor of warmth, so it can take days for a large roast to thaw.

Cooking Unthawed Meats Frozen meats can be cooked without thawing them first, particularly with relatively slow methods such as oven roasting, which give the heat time to penetrate to the center without drastically overcooking the outer portions of the meat. Cooking times are generally 3050% longer than for fresh cuts. Frozen meats can be cooked without thawing them first, particularly with relatively slow methods such as oven roasting, which give the heat time to penetrate to the center without drastically overcooking the outer portions of the meat. Cooking times are generally 3050% longer than for fresh cuts.

Irradiation Because ionizing radiation (p. 782) damages delicate biological machinery like DNA and proteins, it kills spoilage and disease microbes in food, thus extending its shelf life and making it safer to eat. Tests have shown that low doses of radiation can kill most microbes and more than double the shelf life of carefully wrapped refrigerated meats. There is, however, a characteristic radiation flavor, described as metallic, sulfurous, and goaty, which may be barely noticeable or unpleasantly strong.

Beginning in 1985, the U.S. Food and Drug Administration has approved irradiation to control a number of pathogens in meat: first trichinosis in pork, then salmonella in chickens, and E. coli E. coli in beef. A treatment like irradiation is an especially valuable form of insurance for the ma.s.s production of ground meats, in which a single infected carca.s.s can contaminate thousands of pounds of meat, and affect thousands of consumers. But its use remains limited due to consumer wariness. Decades of testing indicate that irradiated meat is safe to eat. But one other objection is quite reasonable. If meat has been contaminated with enough fecal matter to cause infection with in beef. A treatment like irradiation is an especially valuable form of insurance for the ma.s.s production of ground meats, in which a single infected carca.s.s can contaminate thousands of pounds of meat, and affect thousands of consumers. But its use remains limited due to consumer wariness. Decades of testing indicate that irradiated meat is safe to eat. But one other objection is quite reasonable. If meat has been contaminated with enough fecal matter to cause infection with E. coli, E. coli, then irradiation will kill the bacteria and leave the meat edible for three months. However, it will still be adulterated meat. Many consumers set a higher standard than the absence of living pathogens and months of shelf life for the food from which they take daily nourishment and pleasure. People who care about food quality will seek out meat produced locally, carefully, and recently, and for enjoyment within a few days, when it's at its best. then irradiation will kill the bacteria and leave the meat edible for three months. However, it will still be adulterated meat. Many consumers set a higher standard than the absence of living pathogens and months of shelf life for the food from which they take daily nourishment and pleasure. People who care about food quality will seek out meat produced locally, carefully, and recently, and for enjoyment within a few days, when it's at its best.

Cooking Fresh Meat: The Principles We cook meat for four basic reasons: to make it safe to eat, easier to chew and to digest (denatured proteins are more vulnerable to our digestive enzymes), and to make it more flavorful. The issue of safety is detailed beginning on p. 124. Here I'll describe the physical and chemical transformations of meat during cooking, their effects on flavor and texture, and the challenge of cooking meat well. These changes are summarized in the box on p. 152.

Heat and Meat Flavor Raw meat is tasty rather than flavorful. It provides salts, savory amino acids, and a slight acidity to the tongue, but offers little in the way of aroma. Cooking intensifies the taste of meat and creates its aroma. Simple physical damage to the muscle fibers causes them to release more of their fluids and therefore more stimulating substances for the tongue. This fluid release is at its maximum when meat is only lightly cooked, or done "rare." As the temperature increases and the meat dries out, physical change gives way to chemical change, and to the development of aroma as cell molecules break apart and recombine with each other to form new molecules that not only smell meaty, but also fruity and floral, nutty and gra.s.sy (esters, ketones, aldehydes).

Surface Browning at High Temperatures If fresh meat never gets hotter than the boiling point of water, then its flavor is largely determined by the breakdown products of proteins and fats. However, roasted, broiled, and fried meats develop a crust that is much more intensely flavored, because the meat surface dries out and gets hot enough to trigger the Maillard or browning reactions (p. 778). Meat aromas generated in the browning reactions are generally small rings of carbon atoms with additions of nitrogen, oxygen, and sulfur. Many of these have a generic "roasted" character, but some are gra.s.sy, floral, oniony or spicy, and earthy. Several hundred aromatic compounds have been found in roasted meats! If fresh meat never gets hotter than the boiling point of water, then its flavor is largely determined by the breakdown products of proteins and fats. However, roasted, broiled, and fried meats develop a crust that is much more intensely flavored, because the meat surface dries out and gets hot enough to trigger the Maillard or browning reactions (p. 778). Meat aromas generated in the browning reactions are generally small rings of carbon atoms with additions of nitrogen, oxygen, and sulfur. Many of these have a generic "roasted" character, but some are gra.s.sy, floral, oniony or spicy, and earthy. Several hundred aromatic compounds have been found in roasted meats!

Heat and Meat Color The appearance of meat changes in two different ways during cooking. Initially it's somewhat translucent because its cells are filled with a relatively loose meshwork of proteins suspended in water. When heated to about 120F/50C, it develops a white opacity as heat-sensitive myosin denatures and coagulates into clumps large enough to scatter light. This change causes red meat color to lighten from red to pink, long before the red pigments themselves are affected. Then, around 140F/60C, red myoglobin begins to denature into a tan-colored version called hemichrome. As this change proceeds, meat color s.h.i.+fts from pink to brown-gray.

The denaturation of myoglobin parallels the denaturation of fiber proteins, and this makes it possible to judge the doneness of fresh meat by color. Little-cooked meat and its juices are red, moderately cooked meat and its juices are pink, thoroughly cooked meat is brown-gray and its juices clear. (Intact red myoglobin can escape in the meat juices; denatured brown myoglobin has bonded to other coagulated proteins in the cells and stays there.) However, there are a number of oddities about myoglobin that can lead to misleading redness or pinkness even in well-cooked meat (see box). And it's also possible for undercooked meat to look brown and well-done, if its myoglobin has already been denatured by prolonged exposure to light or to freezing temperatures. If it's essential that meat be cooked to microbe-destroying temperatures, then the cook should use an accurate thermometer to confirm that it has reached a minimum of 160F/70C. Meat color can be misleading.

The pigments in cooked and cured meats. Left to right: Left to right: In raw meat, the oxygen-carrying myoglobin is red; in cooked meat, the oxidized, denatured form of myoglobin is brown; in meats cured with nitrite, including corned beef and ham, the myoglobin a.s.sumes a stable pink form (NO is nitric oxide, a product of nitrite); and in uncured meats cooked in a charcoal grill or gas oven, traces of carbon monoxide (CO) acc.u.mulate and produce another stable pink form. In raw meat, the oxygen-carrying myoglobin is red; in cooked meat, the oxidized, denatured form of myoglobin is brown; in meats cured with nitrite, including corned beef and ham, the myoglobin a.s.sumes a stable pink form (NO is nitric oxide, a product of nitrite); and in uncured meats cooked in a charcoal grill or gas oven, traces of carbon monoxide (CO) acc.u.mulate and produce another stable pink form.

Heat and Meat Texture The texture of a food is created by its physical structure: the way it feels to the touch, the balance of solid and liquid components, and the ease or difficulty with which our teeth break it down into manageable pieces. The key textural components in meat are its moisture, around 75% of its weight, and the fiber proteins and connective tissue that either contain and confine that moisture, or release it.

Raw and Cooked Textures The texture of raw meat is a kind of slick, resistant mus.h.i.+ness. The meat is chewy yet soft, so that chewing compresses it instead of cutting through it. And its moisture manifests itself in slipperiness; chewing doesn't manage to liberate much juice. The texture of raw meat is a kind of slick, resistant mus.h.i.+ness. The meat is chewy yet soft, so that chewing compresses it instead of cutting through it. And its moisture manifests itself in slipperiness; chewing doesn't manage to liberate much juice.

Heat changes meat texture drastically. As it cooks, meat develops a firmness and resilience that make it easier to chew. It begins to leak fluid, and becomes juicy. With longer cooking, the juices dry up, and resilience gives way to a dry stiffness. And when the cooking goes on for hours, the fiber bundles fray away from each other, and even tough meat begins to fall apart. All of these textures are stages in the denaturation of the fiber and connective-tissue proteins.

Persistent Colors in Cooked MeatsThoroughly cooked meat is usually a dull, brownish-gray in appearance due to the denaturing of its myoglobin and cytochrome pigments. But two cooking methods can leave well-done meat attractively red or pink.

Barbecued meat, stew meat, a pot roast, or a confit can be surprisingly pink or red inside - if it was heated very gradually and gently. Myoglobin and cytochromes can survive somewhat higher temperatures than the other muscle proteins. When meat is heated quickly, its temperature rises quickly, and some of the muscle proteins are still unfolding and denaturing when the pigments begin to do the same. The other proteins are therefore able to react with the pigments and turn them brown. But when meat is heated slowly, so that it takes an hour or two to reach the denaturing temperature for myoglobin and cytochromes, the other proteins finish denaturing first, and react with each other. By the time that the pigments become vulnerable, there are few other proteins left to react with them, so they stay intact and the meat stays red. The preliminary salting for making a confit (p. 177) greatly accentuates this effect in duck meat.

Meats cooked over wood, charcoal, or gas flames - barbecued pork or beef, for example, or even poultry cooked in a gas oven - often develop "pink ring," which reaches from the surface to a depth of 810 mm. This is caused by nitrogen dioxide (NO2) gas, which is generated in trace amounts (parts per million) by the burning of these organic fuels. It appears that NO2 dissolves at the meat surface to form nitrous acid (HNO dissolves at the meat surface to form nitrous acid (HNO2), which diffuses into the muscle tissue and is converted to nitric oxide (NO). NO in turn reacts with myoglobin to form a stable pink molecule, like the molecule found in nitrite-cured meats (p. 174).

Early Juiciness: Fibers Coagulate One of the two major contracting filaments, the protein myosin, begins to coagulate at about 120F/50C; this lends each cell some solidity and the meat some firmness. As the myosin molecules bond to each other, they squeeze out some of the water molecules that had separated them. This water collects around the solidifying protein core, and is actively squeezed out of the cell by its thin, elastic sheath of connective tissue. In intact muscles, juices break through weak spots in the fiber sheaths. In chops and steaks, which are thin slices of whole muscles, it also escapes out the cut ends of the fibers. Meat served at this stage, the equivalent of rare, is firm and juicy. One of the two major contracting filaments, the protein myosin, begins to coagulate at about 120F/50C; this lends each cell some solidity and the meat some firmness. As the myosin molecules bond to each other, they squeeze out some of the water molecules that had separated them. This water collects around the solidifying protein core, and is actively squeezed out of the cell by its thin, elastic sheath of connective tissue. In intact muscles, juices break through weak spots in the fiber sheaths. In chops and steaks, which are thin slices of whole muscles, it also escapes out the cut ends of the fibers. Meat served at this stage, the equivalent of rare, is firm and juicy.

Final Juiciness: Collagen Shrinks As the meat's temperature rises to 140F/60C, more of the proteins inside its cells coagulate and the cells become more segregated into a solid core of coagulated protein and a surrounding tube of liquid: so the meat gets progressively firmer and moister. Then between 140 and 150F/6065C, the meat suddenly releases lots of juice, shrinks noticeably, and becomes chewier. These changes are caused by the denaturing of collagen in the cells' connective-tissue sheaths, which shrink and exert new pressure on the fluid-filled cells inside them. The fluid flows copiously, the piece of meat loses a sixth or more of its volume, and its protein fibers become more densely packed and so harder to cut through. Meat served in this temperature range, the equivalent of medium-rare, is changing from juicy to dry. As the meat's temperature rises to 140F/60C, more of the proteins inside its cells coagulate and the cells become more segregated into a solid core of coagulated protein and a surrounding tube of liquid: so the meat gets progressively firmer and moister. Then between 140 and 150F/6065C, the meat suddenly releases lots of juice, shrinks noticeably, and becomes chewier. These changes are caused by the denaturing of collagen in the cells' connective-tissue sheaths, which shrink and exert new pressure on the fluid-filled cells inside them. The fluid flows copiously, the piece of meat loses a sixth or more of its volume, and its protein fibers become more densely packed and so harder to cut through. Meat served in this temperature range, the equivalent of medium-rare, is changing from juicy to dry.

Falling-Apart Tenderness: Collagen Becomes Gelatin If the cooking continues, the meat will get progressively dryer, more compacted, and stiff. Then around 160F/70C, connective-tissue collagen begins to dissolve into gelatin. With time, the connective tissue softens to a jelly-like consistency, and the muscle fibers that it had held tightly together are more easily pushed apart. The fibers are still stiff and dry, but they no longer form a monolithic ma.s.s, so the meat seems more tender. And the gelatin provides a succulence of its own. This is the delightful texture of slow-cooked meats, long braises, and stews and barbecues. If the cooking continues, the meat will get progressively dryer, more compacted, and stiff. Then around 160F/70C, connective-tissue collagen begins to dissolve into gelatin. With time, the connective tissue softens to a jelly-like consistency, and the muscle fibers that it had held tightly together are more easily pushed apart. The fibers are still stiff and dry, but they no longer form a monolithic ma.s.s, so the meat seems more tender. And the gelatin provides a succulence of its own. This is the delightful texture of slow-cooked meats, long braises, and stews and barbecues.

How cooking forces moisture from meat. Water molecules are bound up in the protein fibrils that fill each muscle cell. As the meat is heated, the proteins coagulate, the fibrils squeeze out some of the water they had contained and shrink. The thin elastic sheet of connective tissue around each muscle cell then squeezes the unbound water out the cut ends of the cells.

The Challenge of Cooking Meat: The Right Texture Generally, we like meat to be tender and juicy rather than tough and dry. The ideal method for cooking meat would therefore minimize moisture loss and compacting of the meat fibers, while maximizing the conversion of tough connective-tissue collagen to fluid gelatin. Unfortunately, these two aims contradict each other. Minimizing fiber firming and moisture loss means cooking meat quickly to no hotter than 130140F/5560C. But turning collagen to gelatin requires prolonged cooking at 160F/70C and above. So there is no ideal cooking method for all meats. The method must be tailored to the meat's toughness. Tender cuts are best heated rapidly and just to the point that their juices are in full flow. Grilling, frying, and roasting are the usual fast methods. Tough cuts are best heated for a prolonged period at temperatures approaching the boil, usually by stewing, braising, or slow-roasting.

It's Easy to Overcook Tender Meat Cooking tender meat to perfection - so that its internal temperature is just what we want - is a real challenge. Imagine that we grill a thick steak just to medium rare, 140F/60C, at the center. Its surface will have dried out enough to get hotter than the boiling point, and in between the center and surface, the meat temperature spans the range between 140F/60C - medium rare - and 212F/100C - cooked dry. In fact the bulk of the meat is overcooked. And it only takes a minute or two to overshoot medium rare at the center and dry out the whole steak, because meat is cooked but juicy in only a narrow temperature range, just 30F/15C. When we grill or fry an inch-thick steak or chop, the rate of temperature increase at the center can exceed 10F/5C per minute. Cooking tender meat to perfection - so that its internal temperature is just what we want - is a real challenge. Imagine that we grill a thick steak just to medium rare, 140F/60C, at the center. Its surface will have dried out enough to get hotter than the boiling point, and in between the center and surface, the meat temperature spans the range between 140F/60C - medium rare - and 212F/100C - cooked dry. In fact the bulk of the meat is overcooked. And it only takes a minute or two to overshoot medium rare at the center and dry out the whole steak, because meat is cooked but juicy in only a narrow temperature range, just 30F/15C. When we grill or fry an inch-thick steak or chop, the rate of temperature increase at the center can exceed 10F/5C per minute.

Solutions: Two-Stage Cooking, Insulation, Antic.i.p.ation There are several ways to give the cook a larger window of time for stopping the cooking, and to obtain meat that is more evenly done. There are several ways to give the cook a larger window of time for stopping the cooking, and to obtain meat that is more evenly done.

The most common method is to divide the cooking into two stages, an initial high-temperature surface browning, and a subsequent cooking through at a much lower temperature. The low cooking temperature means a smaller temperature difference between center and surface, so that more of the meat is within a few degrees of the center temperature. It also means that the meat cooks more slowly, with a larger window of time during which the interior is properly done.

Another trick is to cover the meat surface with another food, such as strips of fat or bacon, batters and breadings, pastry and bread dough. These materials insulate the meat surface from direct cooking heat and slow the heat penetration.

The Nature of JuicinessFood scientists who have studied the subjective sensation of juiciness find that it consists of two phases: the initial impression of moisture as you bite into the food, and the continued release of moisture as you chew. Juiciness at first bite comes directly from the meat's own free water, while continued juiciness comes from the meat's fat and flavor, both of which stimulate the flow of our own saliva. This is probably why well-seared meat is often credited with greater juiciness despite the fact that searing squeezes more of the meat's own juice out. Above all else, searing intensifies flavor by means of the browning reactions, and intense flavor gets our our juices flowing. juices flowing.

The Effects of Heat on Meat Proteins, Color, and Texture Cooks can also avoid zooming through the zone of ideal doneness by removing the meat from the oven or pan before it's completely done, and relying on lingering afterheat to finish the cooking more gradually, until the surface cools enough to draw the heat back out of the meat interior. The extent of afterheating depends on the meat's weight, shape, and center temperature, and the cooking temperature, and can range from a negligible few degrees in a thin cut to 20F/10C in a large roast.

Knowing When to Stop Cooking The key to cooking meat properly is knowing when to stop. Cookbooks are full of formulas for obtaining a given doneness - so many minutes per pound or per inch thickness - but these are at best rough approximations. There are a number of unpredictable and significant factors that they just can't take into account. Cooking time is affected by the meat's starting temperature, the true temperatures of frying pans and ovens, and the number of times the meat is flipped or the oven door opened. The meat's fat content matters, because fat is less conductive than the muscle fibers: fatty cuts cook more slowly than lean ones. Bones make a difference too. The ceramic-like minerals in bone give it double the heat conductivity of meat, but its frequently honeycombed, hollow structure generally slows its transfer of heat and turns bone into an insulator. This is why meat is often said to be "tender at the bone," more succulent there because less thoroughly cooked. Finally, cooking time depends on how the meat's surface is treated. Naked or basted meat evaporates moisture from its surface, which cools the meat and slows cooking, but a layer of fat or a film of oil forms a barrier to such evaporation and can cut cooking times by a fifth. The key to cooking meat properly is knowing when to stop. Cookbooks are full of formulas for obtaining a given doneness - so many minutes per pound or per inch thickness - but these are at best rough approximations. There are a number of unpredictable and significant factors that they just can't take into account. Cooking time is affected by the meat's starting temperature, the true temperatures of frying pans and ovens, and the number of times the meat is flipped or the oven door opened. The meat's fat content matters, because fat is less conductive than the muscle fibers: fatty cuts cook more slowly than lean ones. Bones make a difference too. The ceramic-like minerals in bone give it double the heat conductivity of meat, but its frequently honeycombed, hollow structure generally slows its transfer of heat and turns bone into an insulator. This is why meat is often said to be "tender at the bone," more succulent there because less thoroughly cooked. Finally, cooking time depends on how the meat's surface is treated. Naked or basted meat evaporates moisture from its surface, which cools the meat and slows cooking, but a layer of fat or a film of oil forms a barrier to such evaporation and can cut cooking times by a fifth.