Transcript Meat Science

Animal Science
Mrs. Rada
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Causes of the Shift
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Refrigerated rail cars and trucks
High real estate values
Closer to livestock
Multi-species plants single species plant
Whole Carcasses  Boxed beef
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Prevent unfair or deceptive practices
Continually updated
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Packer/processor vs. slaughter-only
Expenses
1200 lb steer @
$78/cwt
1200 x .78 = $936
Slaughter cost=$45
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
$994.44 - $981.00 =
Profit: $13.44/head
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Where does all the money go?
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Cost of Livestock=80%
Labor=9%
Other Operating expenses=10%
Net Income=1%
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Purchase meat rather than livestock
Higher profit margins that packers (5 to 15%)
Sausage making, curing, etc.
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Wholesalers/distributors
Retailers
◦ 25% of store receipts are for meat, poultry and
seafood
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Restaurants
◦ 50% of consumers’ food dollar
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Humane Slaughter Act of 1978
◦ Animal handling and stunning
 Stunning
 Render unconscious, not kill
 Methods
 Mechanical (cattle)
 Electrical (pigs)
 Chemical (CO2)-Europe for pigs
 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)
 Eviscerate
 Gutting
 Split
 Wash
 Hot water, steam or organic chemical
 Chill
Carcass
Wholesale
Subprimals
Retail Cuts (grocery store)
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Uniform Retail Meat Identity Standards
(voluntary)
◦ Species
◦ Wholesale (primal) cut
◦ Retail cut
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IMPS (Institutional Meat Purchase
Specifications)
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Size
◦ Beef: largest
◦ Pork: intermediate
◦ Lamb: smallest
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Color of lean tissue
◦ Beef: cherry-red
◦ Pork: reddish-pink
◦ Lamb: dark pink to light red
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Highest value
◦ Middle meats
 Rib and loin
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Next highest value
◦ End meat
 Chuck, round, brisket, shank
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Lowest value
◦ Rough cuts
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the edible flesh of mammals used for food
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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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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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Pork: meat associated with all ages of hog
carcasses.
Chevon: meat from mature goats.
Cabrito: meat from young goats.
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Inspection for wholesomeness is mandatory
and is paid for out of tax dollars.
stamped with a round purple mark if passed
for wholeness
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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.
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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 for quality is voluntary, and the
service is requested and paid for by meat and
poultry producers/processors.
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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.
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Official: Prime, Choice, Select, Standard,
Commercial, Utility, Cutter and Canner
Industry Uses: Prime, Top Choice, Choice,
select and “no roll”
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Determined by maturity (A, B, C, D, E) and
Marbling (Devoid to Extremely Abundant)
◦ Maturity
 A, B = Young
 C, D, E = Old
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Problems with USDA Beef Quality Grades
◦ 1 in 10 carcasses is mis-graded
◦ Marbling is a poor predictor of tenderness
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Prime grade
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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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Choice grade
◦ is high quality
◦ less marbling than Prime
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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
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Standard and Commercial grades
◦ frequently are sold as ungraded or as "store brand"
meat.
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Utility, Cutter, and Canner grades
◦ are seldom, if ever, sold at retail but are used
instead to make ground beef and processed
products.
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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
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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
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Yield grade is most useful when purchasing a
side or carcass of beef for the freezer.
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USDA Grades are not used
Most pork packers use instrument
assessment of percent lean (% muscle)
◦ Fat-O-Meat’er or Ultrasound
◦ Measures fat depth and loin eye area
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Quality is monitored by:
◦ pH
◦ Instrumental color
 Higher number = darker color
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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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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 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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Enjoyment of a meat eating experience is
largely dependent on how it is cooked.
Color changes during heating
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Very rare=130 Degrees F
Rare=140 Degrees F
Medium rare=150 Degrees F
Medium=160 Degrees F
Well done=170 Degrees F
Very well done=180 Degrees F
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Muscle Fibers
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◦ Gradually shrink
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◦ Changes (some
flavors become more
intense)
Collagen fibers
◦ Buckle
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Tenderness
◦ Little change
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Juiciness
◦ Slight Water Loss
Flavor
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Micro-organisms
◦ Active
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Muscle Fibers
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◦ Rapidly shrink
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Collagen fibers
◦ Water Loss
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◦ Begins to solubilize
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Flavor
◦ Changes (some
flavors become more
intense)
Tenderness
◦ Decreases in low
collagen cuts;
increases in high
collagen cuts
Juiciness
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Micro-organisms
◦ Trichinella Spiralis
 Destroyed at 137
degrees F
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Muscle Fibers
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◦ Harden
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Collagen fibers
◦ Rapid loss of juiciness
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◦ Continued solubilization
(if moist heat)
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Tenderness
◦ Decreases rapidly, rapid
toughening;
Tenderization continues
in high collagen cuts
(using moist heat)
Juiciness
Flavor
◦ Changes (some flavors
become more intense)
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Micro-organisms
◦ 149 degrees F for 12-15
minutes destroys
pathogens
◦ Convection
 Circulating air or water
◦ Conduction
 Heat passed between molecules
◦ Radiation
 Radiant waves
◦ 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
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Frying pan
Kettle, crock pot, Dutch oven
Grill
Continuous flow ovens
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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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Moist heat-methods
◦ Braising
 Liquid is added
 Less tender cuts
◦ Cooking in liquid
 Stewing or simmering
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Palatability of meat
◦ Tenderness
 Greatest animal-to-animal variation
◦ Juiciness
◦ Flavor
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Juiciness
◦ Degree-of-doneness
◦ Fat content (marbling)
◦ WHC (pH and rate of decline)
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Flavor
◦ Preparation
 Cooking method and degree-of-doneness
◦ Animal Age
◦ Animal Diet
◦ Fat content (marbling)
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Inadequate Tenderness
◦ #2 concern of beef retailers and restaurateurs
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Two factors in tenderness
◦ Connective tissue factors
 Muscles differ in amount of connective tissue
 Older animal = increase collagen cross-linking =
decrease collagen solubility
◦ 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)
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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, B=Young
 C, D, E=Old (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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USDA Yield Grades
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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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Bacteria
◦ Most predominant
 1 tsp. soil – 2 billion bacteria
 Human body – 100 trillion (outnumber cells 10 to 1)
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Molds and Yeast (fungi)
◦ Minor importance in meat
 Molds like lower water activity
 Yeasts need sugar
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Viruses
◦ Usually not a problem in meat
 Except raw shellfish
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Parasites
◦ Trichinella spiralis (Trichina)
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Causes trichinosis
Pork
Cook to 144 degrees F, freezing, curing to kill
Very rare in US
Feeding garbage to hogs
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High in moisture
Rich in nitrogenous foods
Minerals and accessory growth factors
Fairly favorable pH
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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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Time
◦ Temperature-time relationship is most critical
aspect of food safety
◦ Meat should pass between 40 and 140 degrees in
four hours or less
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Moisture
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Oxygen
pH
◦ Most organisms grow slower at ph above 5.0
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Competing organisms
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Vast majority of bacteria are not harmful
Pathogens
◦ Bacteria that could potentially cause human illness
 Usually requires a large number to make you sick
◦ Examples
 Salmonella
 2 million illnesses
 200-1000 deaths annually
 Escherichia coli (most strains are harmless)
 E. Coli 0157:H7
 .025 Million illnesses
 100-200 deaths annually
 Can be fatal to children
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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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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