Animal Agriculture MEAT SCIENCE

 Describe physiological processes that take place in an animal’s body at death.  Describe the process of ossification.  List the different types of tissue that make up muscle.  Explain the factors that affect the sensation of taste.  Explain why meat is so highly perishable.  Discuss the types of microbes that cause spoilage.  List the factors that favor the growth of microbes.  Discuss the scientific principles behind the preservation of meats. OBJECTIVES IN BASIC SCIENCE

 Explain the steps in the slaughter of meat animals.  Distinguish between quality grading and yield grading of carcasses.  List the wholesale cuts of beef, pork and lamb.  Discuss the factors that affect the palatability of meats.  Discuss the various methods used to preserve meats. OBJECTIVES IN AGRICULTURAL SCIENCE

Wholesale Retail Immobilize (body or part) Kosher Exsanguination Chine Shroud Rigor Mortis Primal KEY TERMS ~

Media Literacy Assignment Read the directions provided. Listen to the NPR Broadcast segment. Answer the corresponding questions. Some questions require you to think! HOW THE U.S. BEEFED UP MEAT PRODUCTION

 Animals leaving the farm to the slaughterhouse are kept as calm as possible, to prevent bruising and to keep the muscles relaxed.  First step at the slaughterhouse is immobilization*.  Regulations for the immobilization process are set by the Federal Humane Slaughter Act, passed in ENTERING THE SLAUGHTERHOUSE

 No method of slaughtering or handling in connection with slaughtering shall be deemed to comply with the public policy of the United States unless it is humane. Either of the following two methods of slaughtering and handling are hereby found to be humane:  (a) in the case of cattle, calves, horses, mules, sheep, swine, and other livestock, all animals are rendered insensible to pain by a single blow or gunshot or an electrical, chemical or other means that is rapid and effective, before being shackled, hoisted, thrown, cast, or cut; or  (b) by slaughtering in accordance with the ritual requirements of the Jewish faith or any other religious faith that prescribes a method of slaughter whereby the animal suffers loss of consciousness by anemia of the brain caused by the simultaneous and instantaneous severance of the carotid arteries with a sharp instrument and handling in connection with such slaughtering. FEDERAL HUMANE SLAUGHTER ACT

 Immobilization may be done in several ways:  CO2 Chamber – animals go to sleep due to lack of oxygen  Electrical Shock – electrical shock to animal’s head & heart  Bolt – head shot delivered via cartridge or compressed air  Electric water bath – heads are submerged in an electrified bath  Kosher* livestock are exempt from Humane Slaughter Act.  Any food produced, killed or prepared according to Jewish dietary laws. These animals are killed via sharp knife to neck.  Immobilized animals are then hung on the rail for exsanguination, skinning, cut-up and inspection. IMMOBILIZATION

 Animals must be quickly bled out to keep from regaining consciousness and to prevent hemorrhaging (escape of blood)  Exsanguination* – blood pressure drops, causing the heart to speed up, which pumps 50% of the blood out and most rest to the organs  The hide and internal organs or entrails are removed.  Liver, Pancreas, intestines, heart, brain, and kidneys are kept.  Federal USDA inspectors inspect all of the internal organs and every carcass to detect any health concern.  Carcasses are prepared for the cooler – beef are sawn down the chine*into halves known as “sides of beef.”  Lamb carcasses are sent to the cooler whole.  Hog carcasses are sent to the cooler as “half hogs.”  Skinned carcasses are wrapped in salt-water shrouds* THE RAIL

CARCASSES ON THE RAIL

 Quickly reduce carcass temperature, to minimize protein degradation and growth of microorganisms.  Rigor Mortis* onsets between 30min – 12 hours and partially relaxes as enzymes break down muscle tissue.  Carcasses require between 18 and 30+ hours to cool. Higher- quality beef may undergo week-long period of aging, which allows further tissue breakdown, tenderizing the meat.  An alternative to the aging period is electrical stimulation.  600 volts speeds up the natural death process, tenderizes the meat, and improves color and texture. THE COOLER

 Newspapers, magazines and media broadcasts educate their viewers on current events.  People who read the newspaper or watch the news on TV are more aware of global and local issues.  As a source of news, the newspaper is almost indispensable to those whose thirst for knowledge is insatiable.  Get caught up on our world’s current events with this activity!  “Legal or Not, Will Americans Ever Buy Horse Meat?”  Time Magazine from March 1, 2013  Read the article and share your thoughts about it in the Ag- Tech Discussion Forum on the Website. ARTICLE REVIEW: HORSE MEAT

 After the carcasses cool, they are graded to USDA standards.  Federal Meat Grading was established in 1925 by the Agricultural Marketing Service (AMS) and the USDA.  Meat grades certify the class, quality and condition of the product examined to conform to uniform standards.  Two types of USDA Grading Scales:  Quality Grades are a prediction of the eating quality (palatablity) of properly prepared meats.  Yield Grades indicate expected yield of edible meat from a carcass – how many cuts of meat will come from that carcass. USDA GRADING

USDA QUALITY GRADE QUALITY GRADES

 Grades are determined by the age of the animal at slaughter and the amount of fat intermingled with the muscle fibers.  Age is determined by the maturity of the cartilage and bones in the carcass. As animals age, cartilage hardens into bone.  Graders inspect the rib cage and vertebrae for the degree of bone and cartilage hardening, called ossification. QUALITY GRADES

USDA QUALITY GRADECHARACTERISTICS OF THAT GRADE Prime Highest quality & marbling. Approx. 3% of supply. Choice Slightly less marbling than Prime. Over 50% of supply. Select Lowest retail grade. Acceptable, but lean and dry. Standard Lower quality, yet economical. Lacks marbling. Commercial Low quality. Lacks tenderness. From older animals. Utility Only used in processed & canned meat products. Cutter Only used in processed & canned meat products. Canner Only used in processed & canned meat products. QUALITY GRADES

 The amount of marbling is determined by examining the longissmus dorsi (rib eye), between 12 th & 13 th rib.  The more white specks of fat that are visible, the higher the grade.  Prime beef has the highest degree of fat in the muscle. Fat gives meat its flavor and juiciness. QUALITY GRADES

USDA QUALITY GRADES

Moderately Abundant Slightly Abundant Moderate Modest Small Slight MARBLING RATINGS

 Yield grades are an estimate of the percentage of boneless, closely trimmed retail cuts that come from the primal* cuts (round, loin, rib and chuck).  USDA Yield Grades for beef are…  1: More than 52.3% lean primal cuts  2: % lean primal cuts  3: % lean primal cuts  4: % lean primal cuts  5: less than 45.5% lean primal cuts  Yield grades start with the size of the rib eye and back fat. YIELD GRADES

 Chilled carcass weight  Amount of internal fat (kidney, pelvic, heart)  Size of rib eye area  Amount of back fat YIELD GRADE FACTORS

WHAT’S A GRADE LOOK LIKE ALIVE?

U.S. BEEF GRADING

 After leaving the cooler, beef carcasses are cut into pieces that are sold to retailers – these pieces are the primal cuts.  Beef – chuck, loin, rib, and round  Pork – shoulder, loin, sides, and ham  Lamb – shoulder, rib, loin, and leg  Poultry – breast, wing, leg, thigh  Primal cuts “cut away” about 30% of excess fat and bone, which saves on shipping costs.  Primal cuts also give retailers an advantage of ordering only what they need, instead of getting everything regardless. THE WHOLESALE CUTS

BEEF PRIMAL CUTS

PORK PRIMAL CUTS

LAMB PRIMAL CUTS

POULTRY PRIMAL CUTS

 Retail cuts are those that the consumer buys at the store. They are sized into portions that require no extra cutting or trimming and are easy to cook.  The most expensive cuts of meat come from the loin.  This is the most tender of the muscle groups.  Products include chops and steaks, such as the T-Bone.  Portions that have been cut away during trimming, or poor retail cuts of meat are often made into sausage or ground. WHOLESALE TO RETAIL

“The Meat Recipe Pack”  Find four recipes from beef, pork, lamb, and poultry cuts.  Beef: Chuck, Rib, Loin, Sirloin, Round, Shank & Brisket, Plate & Flank, Other Cuts  Pork: Leg & Ham, Shoulder, Loin, Side, Other Cuts  Lamb: Leg, Loin, Foreshank & Breast, Rib, Shoulder, Other Cuts  Poultry: Breast, Wing, Thigh, Leg, Other Cuts  That makes 12 recipes. Can’t decide… add both for extras!  Arrange the recipes, with a picture, on MSW or PPT - Dropbox! STUDENT LEARNING ACTIVITY

 Palatability refers to how a food appeals to the palate (taste).  Meat palatability depends on qualities such as…  Appearance  Tenderness  Juiciness  Flavor  Aroma  AS WELL AS THE WAY IT WAS COOKED!  But, since consumers buy most retail meat uncooked, most concern is put into the first qualities*.  Only some stores help consumers with cooking techniques… FACTORS AFFECTING PALATABILITY

 Appearance is the first factor that influences the choice of the consumer – before even reading the price!  Beef, pork and lamb all vary in the shades of red color.  Darker meat is associated with lack of freshness OR meat from an older animal – both of which affect palatability!  Bright red meat gives the appearance of being fresh & wholesome. PALATABILITY & APPEARANCE

 The amount and color of a cut of meat’s fat is also taken into consideration with appearance.  Fat that is yellow in color is less appealing than creamy white color.  Yellow fat is caused by animals that cannot convert carotene (pigment found in feeds, fats and eggs) to Vitamin A.  Grass fed beef are common to have yellow fat, due to being fed an excess of carotene.  Consumers also realize that a cut of meat with a lot of fat and bone has less edible meat or more waste. PALATABILITY & APPEARANCE

 Tenderness is a sensation that has several components, is very difficult to measure and has been studied considerably!  Terms to describe tenderness during chewing include…  Resistance to Tooth Pressure  Softness to Tongue & Cheek  Ease of Fragmentation  Mealiness  Adhesion or Stickiness  Residue After Chewing  On a Meat Science level, it is difficult to describe eating tender vs. tough meat.  It is also difficult to use mechanical devices to measure this too! PALATABILITY & TENDERNESS

 Connective Tissue – tendons, collagen, cartilage and bone  Collagen – abundant protein in active areas  State of Muscle Fibers – how contracted?  Adipose* - little influence on tenderness, but important to palatabilty  In fact, research shows that marbling may act as a lubricant during mastication* - aiding in the digestive process!  Animal age can be determined by cooking…  As the animal gets older, the collagen become less soluble and resistant to cooking. This is seen as the gelatin material in the pan after cooking a pot roast. PALATABILITY & TENDERNESS

 Elastin* is found throughout the ligaments, arteries, and structures of an animal.  These fibers can easily stretch and return to their natural state when released.  Cooking has no affect on this, so cuts of meat high in elastin are tougher to chew. PALATABILITY & TENDERNESS

 Avoid both ends of the juiciness spectrum!  Meats that appear dry, firm and dark (DFD) indicate a lack of freshness or meat from an older animal.  Meats that are extremely moist indicate a pale, soft and exudative (PSE) condition associated with some meats.  PSE conditions are caused by abnormal metabolism after slaughter, low pH levels within meat and stress prior to slaughter.  A meat’s juiciness is important in the perception of palatability to consumers.  Since the juice is made of water and melted fats, it stimulates saliva production, contains flavoring components and assists in digestion – lubricating, softening and fragmenting the meat! PALATABILITY & JUICINESS

 A meat’s flavor often changes after extended storage periods.  The chemical breakdown of nucleotides (flavor components) impart a desired aged flavor.  Oxidation* of fatty acids, known as oxidative rancidity result in a rancid flavor and a unpleasant odor!  This is another reason to keep your eyes on the “use by date!” PALATABILITY & FLAVOR

 Aroma is detected from numerous gaseous aspects of meat that stimulates the nerve endings in the linings of our nasal passages.  The total sensation is a combination of taste AND smell.  The meaty flavor that we taste, combined with the aroma of a cooked steak stimulate the flow of gastric juices and saliva, both which help us digest and increase the apparent juiciness of the meat! PALATABILITY & AROMA