BEEF QUALITY: WHAT IS IT? — HOW TO PRODUCE IT

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BEEF QUALITYWHAT IS IT? HOW TO PRODUCE IT

• Harlan Ritchie
• Department of Animal Science
• Michigan State University
• East Lansing, Michigan 48824

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WHAT IS BEEF QUALITY?

• In fresh, uncooked beef, it is
• Color of the muscle
• Amount of fat
• Subcutaneous fat (external fat on border of
  muscles)
• Intermuscular fat (seam fat between muscles)
• Intramuscular fat (marbling within the muscle)
• Color of the fat (white vs. yellow)

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NORMAL AND DARK-CUTTING BEEF
Dikeman, 1993
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CONSUMERS VISUAL PREFERENCE FOR NORMAL- VS.
DARK-COLORED FRESH BEEF STEAKS a

• Consumers were asked to visually evaluate fresh
  strip loin steaks that differed in color dark
  vs. normal (bright cherry-red).
• Sixty-eight percent of the participants preferred
  normal color and were willing to pay a premium of
  0.23 per kg (1.69 vs. 1.46).
• a Calkins et al. 2000. J. Anim. Sci. 78 (Suppl.
  1)23.

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PRE-HARVEST STRESS AND DARK CUTTNG BEEF a

• Factors that affect the occurrence of dark
  cutting beef are
• Gender (heifers are more excitable than steers)
• Stressful cattle handling procedures
• Mixing cattle from different pens or locations
• Long transportation and holding times
• Large fluctuations in temperature prior to
  harvest
• a Scanga et al. 1998. J. Anim. Sci. 762040.

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WHAT IS BEEF QUALITY?

• In cooked beef, it is
• Flavor
• Juiciness
• Tenderness

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PALATABILITY OF COOKED BEEF

• Palatability of cooked beef is determined by the
  combined effects of flavor, juiciness, and
  tenderness.
• Flavor intensity is related to the amount of
  intramuscular fat (marbling), and the compounds
  that arise from muscle changes during postmortem
  aging.
• Juiciness is determined by amounts of
  intramuscular moisture and marbling that remain
  in the muscle after cooking.
• Tenderness is determined by extent of postmortem
  muscle fiber shortening and breakdown, and the
  amounts of moisture, marbling, and intact
  connective tissue left after cooking.

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CONSUMERS PERCEPTION OF THE IMPORTANCE OF
SENSORY ATTRIBUTES
Frequency,
Miller et al., 1995
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CONSUMER PURCHASE PREFERENCE OF STEAKS VARYING IN
TENDERNESS WHEN PRICED ACCORDINGLY
Purchase preference,
Boleman et al., 1995
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TENDERNESS
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PRE-HARVEST FACTORS THAT AFFECT BEEF TENDERNESS
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BREEDS

• Research has shown that British breeds are more
  tender than Continental breeds and Bos indicus
  breeds are less tender than either Continental or
  British breeds.
• In commercial crossbreeding programs, acceptable
  tenderness can usually be achieved by marketing
  progeny that have
• A minimum of 1/2 British breeding
• A maximum of 1/4 to 3/8 Bos indicus breeding

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9
8
7
6
5
4
Shear Force (Kg)
3
2
1
0
50
100
150
200
0
Days on Feed
(From May et al., 1992)
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EFFECT OF AGE ON BEEF TENDERNESS

• When harvested at an equal fat thickness endpoint
  within an age range of 9 to 30 months, there is a
  tendency for younger cattle to be more tender
  than older cattle
• As cattle advance in age beyond 30 months,
  tenderness declines rapidly, because of
  increasing amounts of connective tissue.

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EFFECT OF RESPIRATORY DISEASE ON BEEF QUALITY a

• Steers having no lung lesions showed the
  following advantages over those having lung
  lesions due to respiratory disease
• Significantly higher marbling scores and USDA
  quality grades
• Significantly improved shear force (tenderness)
  values
• a Gardner et al. 1998. Oklahoma State Univ.
  Research Report.

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EFFECT OF INJECTION SITE LESIONS ON BEEF
TENDERNESS

• Intramuscular injection of various biological and
  pharmaceutical compounds into the outside round
  and top sirloin butt resulted in significantly
  less tender (P lt .001) steaks from these muscles.
• The toughened area covered a radius of 3 inches
  (7.6 cm) from the center of the injection site
  lesion.
• Trimming of the affected tissue represented a
  loss of nearly 6 per animal.
• SOURCE Colorado State Univ. Beef Program Reports
  (1993, 1995, 1996, 1997, 1999)

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EFFECT OF TEMPERAMENT ON ANIMAL WEIGHT GAIN AND
BEEF QUALITY

• Colorado State University researchers scored 531
  feedlot cattle for temperament (1calm
  5extremely excitable). As temperament scores
  increased
• There was a highly significant (P lt .001)
  decrease in average daily gain.
• There was a significant (P lt .01) increase in the
  incidence of dark cutting beef.
• There was a highly significant (P lt .001)
  decrease in meat tenderness as evaluated by shear
  force.
• SOURCE Voisinet et al. 1997. Meat Science
  46(4)367

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HOW IMPORTANT IS MARBLING (INTRAMUSCULAR FAT)?
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WHAT IS THE ROLE OF MARBLING?

• Research has shown that marbling accounts for
  only about 10 of the variation in beef
  tenderness.
• However, recent studies show that some consumers
  credit higher-marbled beef with being
  significantly more tender than it really is
• It appears that these consumers prefer the flavor
  of higher-marbled beef above and beyond any
  tenderness that exists.
• Therefore, it could be very important to identify
  those consumers who prefer high-marbling flavor
  vs. those who prefer low-marbling flavor.

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RELATIONSHIP BETWEEN QUALITY GRADE AND TENDERNESS
OF RETAIL STRIP LOIN STEAKS (Sensory Evaluation
Panel)
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RELATIONSHIP BETWEEN QUALITY GRADE AND TENDERNESS
OF RETAIL LOIN STEAKS

• Quality grades were reasonably effective for
  categorizing retail loin steaks according to
  differences in tenderness when quality grade
  ranged from Select to Prime, but were not
  effective for identifying tenderness differences
  between Select and Low Choice steaks (the narrow
  range in which over 80 of U.S. fed beef is
  graded).
• SOURCE George et al. 1999. J. Anim Sci.
  771735

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AVERAGE HERITABILITY ESTIMATES FOR CARCASS TRAITS
(AGE-CONSTANT) a
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POTENTIAL CORRELATED RESPONSESTO SELECTION FOR
MARBLING

• Favorable
• Decreased shear force (.39)
• Increased preweaning gain (.39)
• Unfavorable
• Increased fat thickness (.37)
• Decreased ribeye area (.14)
• Decreased retail product (.24)
• SOURCED.M. Marshall (1994) genetic correlations
  are in parentheses

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BEEF QUALITY OF HEREFORD AND HEREFORD CROSS
CATTLE VS. USDA CHOICE AND SELECT GRADE CARCASSES

• An extensive study involving 1,000 Hereford and
  Hereford cross steers and heifers, 120 USDA
  Choice, and 120 USDA Select grade carcasses gave
  the following results
• Hereford and Hereford cross carcasses quality
  graded 38 USDA Choice and 56 USDA Select.
• Hereford and Hereford crosses were equal to USDA
  Choice beef in tenderness ratings and superior to
  USDA Select.
• Hereford and Hereford crosses were superior in
  overall palatability ratings to both USDA Choice
  and Select.
• SOURCE Huffines (1992).

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POSTWEANING EFFICIENCY AT VARIOUS MARKET
ENDPOINTS (MARC)
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CAN WE DIRECTLY MEASURE TENDERNESS IN FRESH BEEF?
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INSTRUMENTATION TO EVALUATE BEEF PALATABILITY

• Swatland connective tissue probe
• MARC Tenderness Classification System
• Colorimeter System
• NIR (Near-Infrared Spectroscopy)
• Denver Research Institute Ultrasound System
• HunterLab BeefCam

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HUNTERLAB BEEFCAMSYSTEM FOR EVALUATINGBEEF
PALATABILITY

• Of those carcasses certified as tender using the
  BeefCam system
• 98.6 were found to be tender by shear force
  evaluation
• 79.7 were rated as tender by a trained taste
  panel
• SOURCE Belk (1999)

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BeefCam technology is the most promising
non-invasive technique ever identified for use in
predicting palatability of cooked beef from
measurements taken on the raw carcass.

• G.C. Smith
• Colorado State Univ.

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GENETIC SELECTION FOR BEEF CARCASS TRAITS
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EFFECTIVENESS OF STRATEGIES TO IMPROVE TENDERNESS
a
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THE FUTURE

• EPDs/EBVs (Estimated Breeding Values) for
  tenderness will be available.
• Major genes for tenderness and other carcass
  traits will be identified.
• DNA testing of live cattle for carcass traits
  will be developed.
• Increased emphasis on muscling because of its
  impact on red meat yield.
• Multiple-trait selection technology will combine
  carcass, reproduction, and growth traits into a
  single profit index that can be tailored to the
  objectives of individual cattle breeders.

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THE FUTURE

• I prefer the dreams of the future to the history
  of the past.
• Thomas Jefferson

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THE FUTURE

• Our real task is not to foresee the future, but
  to enable it.
• Saint Exupery in
• Wisdom of the Sands
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