Carcass and meat quality

27 important questions on Carcass and meat quality

%byproducts for chicken; cow and pig

Chicken - 60%
Cow - 42%
Pig - 34%

Environmental interactions associated with meat production, the beneficial effects and negative impacts

Beneficial effects
  • Increased circularity by transforming indigestible plant proteins into digestible proteins
  • make use of otherwise infertile land
  • production of natural fertiliser

Negative impacts
  • Methane production
  • Eutrophication due to N- and P-excretion
  • Land use
  • Water use

What can you tell about the muscle containing 75% water (65-80%)

  • Partly molecularly bound
  • Partly electro-statically bound to charged groups of proteins (up to 80%)
  • Free water trapped within the myofibrillar network

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What is the importance of water in meat production

  • Determines amount of saleable meat
  • Visual retail appearance
  • Important for eating quality
  • Improvement of further processing yields

Chemical composition of the skeletal muscle

Water  -  75%
Proteins  -  19.0%
  • myofibrillar  -  11.5%
  • sarcoplasmatic  -  5.5%
  • Connective tissue  -  2.0%
Fats  -  3.0%
Carbohydrates  -  1.0% (0.5-1.5%)
Minerals and vitamins  -  1.5%

Muscle metabolism (ATP)

Carbohydrates important in development meat quality

Red and white muscle fibers (3)

  • Type I = SO (slow contracting, oxidative)
  • Type II = FOG (fast contracting, oxidative, glycolytic)
  • Type IIB = FG (fast contracting, glycolytic)

What happens in the muscle after stunning and exsanguination?

  • Blood circulation and oxygen supply cease
  • Muscle cells only produce ATP by anaerobic breakdown of glycogen into lactic acid
  • pH falls from ±7.0 to ±5.2 (muscle dependent)
  • Depletion of ATP / energy causes irreversible cross-bridges between actin and myosin, muscle becomes rigid: rigor mortis

Where is looked at for carcass quality?

  • Yield
  • Weight
  • Lean percentage (in primal)
  • Percentage of primals
  • Carcass length
  • Bruises
  • Trim loss

How do we measure carcass quality?

Carcass dissection and classification
  • fiber optic probes
  • visual / carcass conformation

Ultra sound measurements

What is Visual classification of conformation? And what are the codes?

  • AA = extreme muscular
  • A = good to very good musculature
  • B = average musculature
  • C = thin musculature

Fresh meat quality & eating quality

Fresh meat quality
  • Colour, colour stability
  • Waterholding capacity (drip)
  • Marbling, etc.

Eating quality
  • Tenderness
  • Juiciness
  • Aroma

Suitability for further processing

Basic factors that determine meat quality

  • Muscle composition
    • fat / fatty acids
    • collagen / binding tissue
    • muscle fibre type
    • pigment
  • Sarcomere length
  • Muscle energy store at slaughter
    • glycogen content
  • Muscle energy breakdown after slaughter
    • rate of lactate formation

Cold shortening [sarcomere length and tenderness]

  • Toughness induced by chilling meat before the onset of rigor mortis
  • Occurs if muscle is cooled below 10*C before rigor is complete, i.e. Before the pH drops below 6.1
  • Calcium that is stored in the muscle leaks out, when T becomes below 10*C, and when there is still glycogen/energy present the will cause extreme muscle contraction
carcass rigor is not complete until ±
  • beef - 10 to 30 hours postmortem
  • lamb - 10 to 20 hours postmortem
  • pork - 1 to 8 hours postmortem
  • chicken - 0.3 to 4 house postmortem

What are the major measurable meat quality parameters

  • pH (early postmortem and ultimate)
  • Water holding capacity (drip loss)
  • Color
  • Marbling (IMF)
  • Shear Force (tenderness)

Colour the L* and a* value =

Lightness: L* value from 0 (black) to 100 (white)

Redness: a* values ranging from -60 (green) to 60 (red)

IMF - NPPC Marbling Scores

intermuscular fat is causing it...??? > tast/quality goes down

Factors influencing eating quality

  • Marbling (IMF)
  • pHu
  • Ageing

Beef tenderness  determinants:

  • Connective tissue
  • Myofibrillar proteins
    • short sarcomeres --> tough meat
    • cold shortening
    • tender stretching
      • achilles tendon = common way
      • pelvic bone (better stretch)
  • Ageing
    • proteolytic enzymes: calpains / cathepsins

Production chain factors on meat quality

  • Farm
    • genetics
    • nutrition
    • on-farm handling
  • transport
    • loading/unloading
    • duration
  • pre-slaughter handling
    • lairage
    • pre-stunning handling

What does feed withdrawal influence

  • Energy store at slaughter (glocogen level, pHu)
  • Dressing percentage of carcass
  • Diet composition is another way to influence pHu


important pork production chain factor

From pig to carcass (some steps)

  • Stun to stick interval
  • Horizontal versus vertical bleeding
  • Bleeding time
  • Scalding temp / time or skin time
  • Evisceration time
  • Splitting accuracy
  • etc


Keep time between sticking and chilling as short as possible

What are the effects of rapid chilling

  • Less carcass shrinkage
  • slower rate of pH
    • less protein breakdown
    • less drip loss and better color
  • higher ultimate pH
    • better water holding capacity / color

Why is fast chilling of beef carcasses necessary?

  • To reduce microbial growth
  • To improve colour stability
  • To reduce development of fat rancidity
  • To increase chiller capacity
  • To minimize evaporative loss


However, too fast chilling of Beef/Veal/Lamb carcasses can cause cold shortening = severe toughening of the meat

What does electrical stimulation (ES) do?

  • Pulses of electrical current stimulate muscle to contract
    • each contraction and relaxation uses up energy and turns glycogen into lactate
    • rigor is accelerated
    • may enhance tenderisation during conditioning

Value of pHu - water holding capacity =

  1. More saleable product
  2. Increased premium product
  3. More saleable cooked product

Usefulness of DFD meat products

Suitable for
  • Bologna tupe sausage
  • cooked ham (the self life os slices is reduced)
  • Cured meat cuts (Kasseler)
  • Meat cuts for immediate frying or grilling

Unsuitable for
  • Cured raw meat products
  • Raw ham
  • Leg ham
  • Meat cuts packed in foils
  • Fermented sausage

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