Meat Science

1
Meat Science

• Animal Science
• Mrs. Rada

2
Historical Shift Westward

• Causes of the Shift
• Refrigerated rail cars and trucks
• High real estate values
• Closer to livestock
• Multi-species plants? single species plant
• Whole Carcasses ? Boxed beef

3
Packers and Stockyards Act (1921)

• Prevent unfair or deceptive practices
• Continually updated

4
Packers

• Packer/processor vs. slaughter-only

5
Meat Packer Economics

• Expenses
• 1200 lb steer _at_ 78/cwt
• 1200 x .78 936
• Slaughter cost45
• Total 936 45 981
• Drop by-products
• Drop credit 7.90/cwt

• Income
• 63 dressing percent
• 1200 x .63 756 lb car.
• 119/cwt or 1.19/lb
• 756 x 1.19 899.64
• Total Drop Credit
• 1200 x .079 94.80
• 899.64 94.80 994.44

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Meat Packer Economics cont.

• 994.44 - 981.00
• Profit 13.44/head

7
Meat Packer Balance Sheet

• Where does all the money go?
• Cost of Livestock80
• Labor9
• Other Operating expenses10
• Net Income1

8
Processors

• Purchase meat rather than livestock
• Higher profit margins that packers (5 to 15)
• Sausage making, curing, etc.

9
Other purchasers of meat

• Wholesalers/distributors
• Retailers
• 25 of store receipts are for meat, poultry and
  seafood
• Restaurants
• 50 of consumers food dollar

10
Slaughter of Livestock

• Humane Slaughter Act of 1978
• Animal handling and stunning
• Stunning
• Render unconscious, not kill
• Methods
• Mechanical (cattle)
• Electrical (pigs)
• Chemical (CO2)-Europe for pigs

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Slaughter of Livestock

• Sticking (exsanguination)
• Standard vs. Kosher vs. Halal
• Kosher Rabbi must certify and no stunning
• Halal Muslim
• Skinning
• Beef, lamb and sometimes pork
• Hide (pelt) puller
• Hair removal (pork)
• Scalding
• Singer (burn off)

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Slaughter of Livestock

• Eviscerate
• Gutting
• Split
• Wash
• Hot water, steam or organic chemical
• Chill

13
Carcass Fabrication

• Carcass
• Wholesale
• Subprimals
• Retail Cuts (grocery store)

14
Meat-cut Standards

• Uniform Retail Meat Identity Standards
  (voluntary)
• Species
• Wholesale (primal) cut
• Retail cut
• IMPS (Institutional Meat Purchase Specifications)

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Species differentiation

• Size
• Beef largest
• Pork intermediate
• Lamb smallest
• Color of lean tissue
• Beef cherry-red
• Pork reddish-pink
• Lamb dark pink to light red

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Relative value

• Highest value
• Middle meats
• Rib and loin
• Next highest value
• End meat
• Chuck, round, brisket, shank
• Lowest value
• Rough cuts

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Meat Terminology
18
Meats

• the edible flesh of mammals used for food

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Specific Terminology

• Poultry the edible flesh of poultry used for
  food
• Beef the meat from mature bovines that are
  generally over 12 months of age.

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Specific Terminology

• Veal the meat from very young calves, usually
  less than 3 months of age.
• Mutton the meat from mature ovine carcasses that
  fail to show a break joint on the front foreleg.
• Lamb meat from lambs or young sheep, up to about
  one year of age that shows a break joint in the
  foreleg.

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Specific Terminology

• Pork meat associated with all ages of hog
  carcasses.
• Chevon meat from mature goats.
• Cabrito meat from young goats.

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Inspection of Meat
23
Inspection of Meat

• Inspection for wholesomeness is mandatory and is
  paid for out of tax dollars.
• stamped with a round purple mark if passed for
  wholeness

24
Federal Meat Inspection Act and the Poultry
Products Inspection Act

• Food Safety and Inspection Service inspects all
  raw meat and poultry sold in interstate and
  foreign commerce, including imported products.
• The Agency monitors meat and poultry products
  after they leave federally inspected plants.

25
Voluntary Federal inspection

• for animals not covered under mandatory
  inspection (i.e., buffalo, rabbit, reindeer, elk,
  deer, antelope)
• handled under the Agricultural Marketing Act
• gives the Secretary of Agriculture the authority
  to take whatever steps are necessary to make the
  product marketable
• must pay an hourly fee for the service

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Grading of Meat
27
Grading of Meat

• Grading for quality is voluntary, and the service
  is requested and paid for by meat and poultry
  producers/processors.

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Beef is graded as whole carcasses in two ways

• quality grades - for tenderness, juiciness, and
  flavor and
• yield grades - for the amount of usable lean meat
  on the carcass.
• There are eight quality grades for beef.
• Quality grades are based on the amount of
  marbling (flecks of fat within the lean), color,
  and maturity.

29
USDA Quality Grades (Beef)

• Official Prime, Choice, Select, Standard,
  Commercial, Utility, Cutter and Canner
• Industry Uses Prime, Top Choice, Choice, select
  and no roll

30
USDA Quality Grades (Beef)

• Determined by maturity (A, B, C, D, E) and
  Marbling (Devoid to Extremely Abundant)
• Maturity
• A, B Young
• C, D, E Old
• Problems with USDA Beef Quality Grades
• 1 in 10 carcasses is mis-graded
• Marbling is a poor predictor of tenderness

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Quality Grades

• Prime grade
• is produced from young, well-fed beef cattle
• abundant marbling
• generally sold in restaurants and hotels
• Prime roasts and steaks are excellent for
  dry-heat cooking (i.e., roasting, broiling, and
  grilling).

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Quality Grades

• Choice grade
• is high quality
• less marbling than Prime

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Quality Grades

• Select grade
• is very uniform in quality
• normally leaner than the higher grades
• It is fairly tender, but, because it has less
  marbling, it may lack some of the juiciness and
  flavor of the higher grades

34
Quality Grades

• Standard and Commercial grades
• frequently are sold as ungraded or as "store
  brand" meat.
• Utility, Cutter, and Canner grades
• are seldom, if ever, sold at retail but are used
  instead to make ground beef and processed
  products.

35
USDA Yield Grades (Beef)

• Cutability
• 1, 2, 3, 4, 5
• Determined by hot carcass weight, fat thickness,
  rib eye area, and percentage of kidney, pelvic,
  and heart fat (KPH)
• Very accurate if accurately applied
• 1 out of 4 carcasses is mis-graded

36
Yield grades

• Range from "1" to "5"
• indicate the amount of usable meat from a carcass
• Yield grade 1 is the highest grade and denotes
  the greatest ratio of lean to fat
• yield grade 5 is the lowest yield ratio
• Yield grade is most useful when purchasing a side
  or carcass of beef for the freezer.

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Pork

• USDA Grades are not used
• Most pork packers use instrument assessment of
  percent lean ( muscle)
• Fat-O-Meater or Ultrasound
• Measures fat depth and loin eye area
• Quality is monitored by
• pH
• Instrumental color
• Higher number darker color

38
Veal/Calf

• There are five grades for Veal/Calf prime,
  choice, good, standard, and utility.
• Prime and choice grades are juicier and more
  flavorful than the lower grades.
• Because of the young age of the animals, the meat
  will be a light grayish-pink to light pink,
  fairly firm and velvety.
• The bones are small, soft, and quite red.

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Lamb

• There are five grades for lamb.
• Normally only two grades are found at the retail
  level prime and choice
• Prime grade
• is very high in tenderness, juiciness, and
  flavor.
• Its marbling enhances both flavor and juiciness.
• Choice grade
• has slightly less marbling than prime, but still
  is of very high quality.

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Lamb

• Lamb is produced from animals less than a year
  old.
• Since the quality of lamb varies according to the
  age of the animal, it is advisable to buy lamb
  that has been USDA graded.

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Meat Cooking
42

• Enjoyment of a meat eating experience is largely
  dependent on how it is cooked.
• Color changes during heating
• Very rare130 Degrees F
• Rare140 Degrees F
• Medium rare150 Degrees F
• Medium160 Degrees F
• Well done170 Degrees F
• Very well done180 Degrees F

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Up to 122 Degrees F

• Muscle Fibers
• Gradually shrink
• Collagen fibers
• Buckle
• Tenderness
• Little change
• Juiciness
• Slight Water Loss

• Flavor
• Changes (some flavors become more intense)
• Micro-organisms
• Active

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122 to 149 Degrees F

• Muscle Fibers
• Rapidly shrink
• Collagen fibers
• Begins to solubilize
• Tenderness
• Decreases in low collagen cuts increases in high
  collagen cuts

• Juiciness
• Water Loss
• Flavor
• Changes (some flavors become more intense)
• Micro-organisms
• Trichinella Spiralis
• Destroyed at 137 degrees F

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Up to 149 Degrees F

• Muscle Fibers
• Harden
• Collagen fibers
• Continued solubilization (if moist heat)
• Tenderness
• Decreases rapidly, rapid toughening
  Tenderization continues in high collagen cuts
  (using moist heat)

• Juiciness
• Rapid loss of juiciness
• Flavor
• Changes (some flavors become more intense)
• Micro-organisms
• 149 degrees F for 12-15 minutes destroys pathogens

46
Heat transfer

• Convection
• Circulating air or water
• Conduction
• Heat passed between molecules
• Radiation
• Radiant waves

47
Equipment

• Conventional range
• Oven-convection and radiation
• Stove-conduction
• Forced air convection oven
• Faster cooking
• Impingement oven
• High pressure air or water
• Very fast cooking
• Microwave oven
• No browning of meat surface

48
Equipment

• Frying pan
• Kettle, crock pot, Dutch oven
• Grill
• Continuous flow ovens

49
Methods of Cooking Meat

• Dry-Heat Methods
• Broiling
• Meat directly exposed to heat source
• Steaks and chops
• Panfrying
• Thin cuts of meat, ground meat
• Stir Frying
• Deep fat frying
• Only for very tender meat cuts
• Roasting
• Uncovered, no water added
• Larger, more tender cuts

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Methods of Cooking Meat

• Moist heat-methods
• Braising
• Liquid is added
• Less tender cuts
• Cooking in liquid
• Stewing or simmering

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Palatability and Tenderness
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Meat Palatability

• Palatability of meat
• Tenderness
• Greatest animal-to-animal variation
• Juiciness
• Flavor

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Meat Palatability

• Juiciness
• Degree-of-doneness
• Fat content (marbling)
• WHC (pH and rate of decline)

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Meat Palatability

• Flavor
• Preparation
• Cooking method and degree-of-doneness
• Animal Age
• Animal Diet
• Fat content (marbling)

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Meat Tenderness

• Inadequate Tenderness
• 2 concern of beef retailers and restaurateurs

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Meat Tenderness

• Two factors in tenderness
• Connective tissue factors
• Muscles differ in amount of connective tissue
• Older animal increase collagen cross-linking
  decrease collagen solubility

57
Meat Tenderness

• Myofibrillar factors
• Sarcomere length (ex. Cold shortening)
• Shorter sarcomere length results in tougher meat
• Postmortem protein degradation
• Dry aging vs. wet agin
• Majority of tenderization occurs within first 7
  days postmortem
• Cytoskeletal (structural) proteins are degraded
  (broken down)

58
Meat Grading
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Beef

• USDA Quality Grades
• Official Prime, Choice, Select, Standard,
  Commercial, Utility, Cutter, Canner
• Industry Uses Prime, Top Choice, Choice, Select,
  no roll
• Determined by maturity (A, B, C, D, E) and
  marbling (devoid to extremely abundant)
• Maturity
• A, BYoung
• C, D, EOld (Hardbone)
• Problems with USDA beef quality grades
• 1 in 10 carcasses is mis-graded
• Marbling is a poor predictor of tenderness

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Beef

• USDA Yield Grades

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Meat Food Safety
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Microorganisms

• Need microscope to see
• Food borne microorganisms
• Intoxication or infection
• Intoxication
• Microorganism produced toxin on food
• Ingested toxin causes sickness
• Infection
• Live organism is ingested and grows inside host
• Produces toxin inside host

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Types of Microorganisms

• Bacteria
• Most predominant
• 1 tsp. soil 2 billion bacteria
• Human body 100 trillion (outnumber cells 10 to
  1)
• Molds and Yeast (fungi)
• Minor importance in meat
• Molds like lower water activity
• Yeasts need sugar

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Types of Microorganisms

• Viruses
• Usually not a problem in meat
• Except raw shellfish
• Parasites
• Trichinella spiralis (Trichina)
• Causes trichinosis
• Pork
• Cook to 144 degrees F, freezing, curing to kill
• Very rare in US
• Feeding garbage to hogs

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Meat is ideal for bacterial growth

• High in moisture
• Rich in nitrogenous foods
• Minerals and accessory growth factors
• Fairly favorable pH

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Factors affecting microbial growth

• Temperature
• Mismanagement of temperature is 1 cause of
  foodborne disease
• Most organisms grow best between 40 and 140
  degees F
• Keep meat hot or cold
• USDA recommends cooking ground meat at 160
  degrees
• Muscle interior is considered sterile

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Factors affecting microbial growth

• Time
• Temperature-time relationship is most critical
  aspect of food safety
• Meat should pass between 40 and 140 degrees in
  four hours or less
• Moisture

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Factors affecting microbial growth

• Oxygen
• pH
• Most organisms grow slower at ph above 5.0
• Competing organisms

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Pathogenic Bacteria

• Vast majority of bacteria are not harmful
• Pathogens
• Bacteria that could potentially cause human
  illness
• Usually requires a large number to make you sick

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Pathogenic Bacteria

• Examples
• Salmonella
• 2 million illnesses
• 200-1000 deaths annually
• Escherichia coli (most strains are harmless)
• E. Coli 0157H7
• .025 Million illnesses
• 100-200 deaths annually
• Can be fatal to children

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Other Meat Safety Issues

• Pesticides and other chemical residues
• 99.99 of pesticides in human diet are natural
• Smith et al., 1992
• Tested beef for 25 pesticides, 500 tests 0
  violative
• No difference between organic, natural, and
  conventional beef
• Risk of illness
• 1 in 1,000,000

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Other Meat Safety Issues

• Antibiotics
• Residue in human food is not a problem
• Infectious multiple-antibiotic resistance
  transfer
• Create resistant strains of bacteria
• Potential problems
• Anabolic steroids/hormones
• Growth promotant
• 58 more estrogen in implanted beef
• 1.2 ng estrogen in non-implanted beef
• 1.9 ng estrogen in implanted beef
• Daily production of estrogen by human body
• Men 136,000 ng
• Women 1,000,000 ng