28 Meat Grading and Cutting
Meat grading and cutting are important commercially - but
the details change from time to time and from place to place. The
objective of this brief overview is to highlight a few fundamentals
unlikely to change.
28.1 Principles of grading
- The purpose of meat grading is to
describe the value of a carcass in clearly defined terms
useful to the meat industry.
- Both the buyer and the
seller need an impartial third party to grade the carcass.
- If the buyer and the seller have their own
system of payment for high and for low value carcasses, they can save
money by not having the carcass graded.
- Grading facilitates long distance transactions and
contracts for future
shipments in which one or both parties have not yet examined the
- Three major factors determine
the value of a carcass relative to market conditions, (1) carcass weight, (2)
the cutability or yield of
salable meat, and (3) the quality
of the lean meat.
- All three factors are continuous variables measured
absolute terms, such as weight, or in relative terms, such as those
used by a
- In scientific experiments, accurate carcass evaluation is
necessary to search for minor differences between carcasses. But a less
accurate system is adequate for commercial transactions, and the
spectrum of carcass properties is subdivided into a relatively small
grades in a step‑wise sequence.
- Thus carcasses placed in the same
grade may exhibit small differences, but carcasses placed into
different grades should exhibit much larger, and commercially
- The important grading systems are for
beef, pork and poultry. Systems exist for the other species but they
are mostly ignored or used in a very simple way.
28.2 Beef grading
The first step of most beef grading systems is to place the carcass
into a maturity group. Although many beef animals arrive at the
abattoir with some identification, often an electronic implant, the
grading system must give equal treatment to animals without
identification - where animal age is
unknown. Young cattle produce more tender beef than old cattle -
so grading must first sort animals using an estimate of their
age. Dentition would be useful - but the head is usually removed
before grading starts. Most grading systems use the degree of
replacement of cartilage by bone in parts of the skeleton revealed as
the carcass is split into left and right sides.
CHARACTERISTICS (CATTLE LESS THAN ABOUT TWO YEARS)
1. Cartilaginous caps on the first few thoracic vertebrae
not more than half ossified.
2. First few lumbar vertebrae with
evidence of cartilage or a red line on the neural spinous process
3. Neural process is red and porous spinous when
4. Medial view shows ribs are narrow, round, and red.
5. The sternebrae are not fused.
CHARACTERISTICS (CATTLE MORE THAN ABOUT TWO YEARS)
1. Thoracic caps more than half ossified.
2. No cartilage or red line on lumbar vertebrae.
3. Hard, white, flinty neural processes when split.
4. Wide, flat, white ribs.
5. Ossified sternum.
Having eliminated older animals, attention is then usually
directed at yield grading in
the top grade of beef. Yield grading will be used by the purchaser to
estimate the yield of meat from the carcass. Obviously, a carcass
with a high meat yield is worth more than a carcass with a low yield.
Yield grading is based on the fact it is extremely difficult to assess
the bulging and length of muscles, but quite easy to assess the amount
of fat on the carcass. If we assume
the amount of bone is approximately constant (usually but not always
true), then carcass weight which is not fat - must be meat. However,
any reliable information on muscularity greatly improves this indirect
estimate using fat alone. Thus, in many countries, carcasses are split
through the posterior part of the ribcage to expose the Longissimus dorsi (usually the Longissimus thoracis which is the
part of the Longissimus dorsi
running the rib region). Some feature of the size of this muscle (area,
length and/or depth) is used to help estimate meat yield. Can you see
an obvious source of error? What will happen if we have an animal with
a longer vertebral column than normal?
A long carcass may have a high meat yield, even though its
muscles may not be bulging. (Review
Lecture 24 again if this does not make sense.)
- The neural process is dorsal to the neural arch protecting the
spinal cord. It is where the two sides of the arch join together. Other
names are dorsal process and spinous process.
- Age estimates can only be approximate because, firstly, small-
and large-framed cattle mature at different rates. Secondly, the
characteristics given above are subjective.
USED TO ESTIMATE MEAT YIELD
(1) An estimate of
subcutaneous fat thickness, usually made where the Longissimus dorsi is exposed.
(2) An estimate of the visceral
fat remaining on the carcass,
(3) An estimate of the cross
sectional area of the Longissimus dorsi muscle at the separation of the
forequarter and the hindquarter.
(4) Hot carcass weight, or
an estimate made from the cold carcass weight (cold weight x 1.02).
FEATURES REQUIRED FOR HIGH-QUALITY MEAT
(1) A check the fat is not too yellow.
(2) A check the muscles are not too dark.
- Acceptable fat colour varies geographically. Consumers can
detect the carotene content of fat, which is usually coupled with a
diterpenoid taste in the lean (both from forage-fed animals).
Some consumers like this taste (I do!), others do not. When grain fed
animals dominate the market, grading systems typically down grade beef
with yellow fat. Why? Because, historically, consumers in these areas
associate yellow fat with meat from old cows. When the rich countries
run out of oil, and cattle once again are valued as self-mobile,
self-feeding meat producers - I suspect white fat will be quietly
dropped as a requirement for top grade beef.
- Down-grading dark meat is far more reasonable. Remember dark-cutting beef in lecture
- Having graded the beef carcass, it usually stamped with a hammer
or roller coated with edible dye. Thus, the cautious consumer usually
gets to see some or all of the stamp on the fat covering a joint of
meat. The grade stamp usually has a numerical code to identify
the plant of origin.
Summary. Most beef grading systems
attempt to sort carcasses on the basis of both meat quality and meat
yield. But the system is far from perfect. A young animal with tough
meat will outrage consumers. An older animal with tender meat will be
wasted. In the future, there may be better methods of beef grading -
using image analysis, ultrasonics and meat quality probes. Beef grading
tends to be forward looking - the grading information is
passed onto meat cutters (estimated yield) and consumers (meat quality
assurance). Sometimes the information is fed back to producers to award
a premium for a high-quality carcass.
28.3 Pork grading
- Pork grading tends to be far less concerned with meat quality,
and often simply becomes a feed-back system for rewarding producers of
lean carcasses at an optimum weight. In some countries all pork is
regarded as equal in quality - a foolish mistake in the long-term. In
other countries, a serious effort may be made to probe pork carcasses
to check their meat quality - primarily to reject PSE pork and give a
premium for marbling fat.
- A advantage in grading pork is the skin often remains on the
carcass until the day after slaughter. This gives the fat a
well-defined outer boundary, and fat depth probes may be used to
automate data collection on fat depth.
- The probe pushes into the carcass and an optical diode detects
the depth of the boundary between fat and lean.
- Some probes check for PSE and marbling in the muscle.
- However, ultrasonic methods can make multiple measurements as a
pork carcass is pulled through a U-shaped frame - thus giving a
superior estimate of subcutaneous fat depth.
- Thus, at present, some countries use an optical probe at one
point while other countries use ultrasonics.
28.4 Poultry grading
- The primary decision in poultry grading is based on weight and
- Broiler or fryer chickens are typically up to 8 weeks in age,
weighing 0.8 to 1.8 kg.
- Roaster chickens are typically older, weighing over 1.8 kg.
- Comparable separations are made for turkeys, ducks and geese,
with the younger, smaller birds obtaining a premium (they are more
expensive to produce per kilogram - but they are very tender and can be
- Poultry with tender
meat are typically identified by their soft, pliable and
smooth‑textured skin, and by their
flexible sternal cartilages.
- The classes of poultry with meat of an
intermediate level of tenderness are identified by their greater age,
skin, and less flexible sternal cartilage.
- The mature classes of poultry requiring prolonged cooking are the
rooster, mature hen chickens, mature hen
or tom turkeys, mature duck and mature goose. These classes have tough
coarse skin, and stiff sternal cartilages
- In chickens, young birds
have unwrinkled combs with sharp points. In older birds, the comb
wrinkled with blunt points.
- Young ducks have soft bills,
while older ducks have hard bills.
- Plumage becomes worn and
faded in older birds (unless they have just molted).
- With age, subcutaneous fat
becomes darker and becomes lumpy under the main feather tracts.
- With age, the pelvic bones
become less pliable.
- With age, scales become
larger, rough and slightly raised.
- In old birds, the oil sac
becomes enlarged and sometimes hardened.
- With age, male chickens and
turkeys may develop long spurs.
- With age, the cartilaginous
rings of the trachea become stiff in ducks and geese.
28.5 Recognition of cuts of meat
taking a course in meat cutting, the most we can hope for here is for
students to recognize where a meat cut originates in the carcass.
Meat cutting is as variable as language. Sirloin steaks
may be Longissimus lumborum in
England (left side of diagram above), or
Gluteus medius in
North America (right side of diagram above). You only need to learn the cuts where
Steaks and chops along the vertebral column usually
command a premium price based on tenderness. Cuts through the proximal
limb regions are intermediate in price. Finally, cuts from the neck and
distal limbs are lest expensive.
The recognition of the species of meat when
cuts of beef, pork and lamb are displayed for sale as top‑quality fresh
based on the colour of the lean and on the size of whole muscles and
lean has the deepest colour, and pork has the lightest colour. Lamb and
intermediate, depending on the age of the animal. Veal from entirely
calves is extremely pale.
If marbling fat is present as wavy lines and dots of
white fat in the lean, it is very conspicuous against the dark color of
lean in beef, but is sometimes less visible in pork.
Pork exhibits the greatest
variation in depth of colour between different muscles.
Pork often has the
whitest fat, and beneath the subcutaneous fat may be seen the thick
of the pork carcass. Some pork cuts retain their skin.
- To identify a cut of meat, first decide
whether an unidentified cut is from the left or right side of the
carcass. Then ascertain its position and orientation
in the carcass. Do not forget that left and right sides of the carcass
mirror images, and the two flat surfaces of a chop or steak from one
of the carcass may also form mirror images. This is particularly
identifying muscles from diagrams.
- Examine the surfaces of the cut of meat,
and look for a medial surface, as indicated by vertebrae,
sternum, pubis, ribs, adductor muscle, gracilis, etc.
- Surfaces once
part of the lateral surface of the carcass usually bear traces of
untrimmed subcutaneous fat, often with a grade stamp.
- The orientation of a cut
of meat may be indicated by the extent to which the cut of meat is
abdomen is narrower than the thorax in an eviscerated carcass, and the
are tapered from proximal to distal. The dorsal spines of most of the
vertebrae project posteriorly. The anterior ribs are shorter than the
- Look for a series of exposed
blocks of porous bone. If a deep groove (neural canal) runs through the
the bones are vertebrae from along the animal's backbone. If no groove
present, the bones may be part of the sternum. However, if a carcass
poorly split into sides, the midline cut may miss the neural canal.
- Look for rounded cross
sections of bone from a limb, but remember part of the shaft
of the ilium also is round in cross section.
- The whole hindlimb is rounded in
cross section, but the forelimb is flattened because it is located
- When the ilium has a rounded cross section in a whole sirloin,
muscle mass is lop‑sided, and there is some trace of the sacrum on the
the cut of meat. The more posterior part of the shaft of the ilium is
triangular in cross section.
- When the femur has a
rounded cross section in the round, ham or hind leg, it is almost in
of a circle of meat.
- When the humerus or the shaft of the
scapula have a rounded cross section in the chuck or arm region, it is
alongside a series of transected ribs, and the muscle mass of the limb
in cross section.
- Look for a section that has
been cut through a flat bone. If rigidly part of the body of a
and if it is narrow, it may be a wing‑like transverse process of a
vertebra from the loin. If it is rigidly part of a vertebra and
is dorsal to the neural canal, and if it is one of a series of wide
sections of bone, it may be a dorsal spine of a thoracic vertebra from
blade or rib region of the carcass. If it is curved and if it is
jointed to a vertebra, it is probably the dorsal part of a rib.
If it is parallel to a vertebral process, or if it is joined by
cartilage to a
vertebra, it may be the flat part of the ilium from the sirloin.
- If it is isolated by itself in the meat, or if it is shaped
like a letter T, it
is probably the scapula.
- If there are no bones in the
cut of meat, and if it is a flat slab of meat composed of several
flat muscles, it is probably part of the flank or abdominal wall.
- If the cut of meat has large
vertebrae with a complex shape, and if the outer surface of the meat is
and ragged, the meat is probably from the neck.
- If the outer surface of the
cut of meat contains a flat rounded area of bone with a dimpled surface
traces of dried cartilage, the bone is the pubis from the rump region.
- Look for a hole in the meat
where the carcass might have been suspended from a large hook or
indicates a hind leg, or the heel of the round in beef. In beef, the
tendon is hard, dry, pale yellow in color, and extremely strong
- Look for a series of
parallel ribs. The anterior ribs are shorter than the posterior ribs,
anterior ribs connect directly to the sternum.
- Look for a long flap of
muscle that runs diagonally over the medial surfaces of the ribs. This
muscle is the diaphragm. The ventral part of the diaphragm is anterior
posterior part. In the beef carcass, the anterior part of the diaphragm
in the plate, and the posterior part of the diaphragm appears at the
- Look for a ball and socket
joint. The socket of the scapula in the chuck region of the carcass is
shallow. The socket that forms the acetabulum of the pelvis is narrow
and there may be a trace of the ligament which holds the head of the
the socket. In pork and lamb, the acetabulum may be contained in the
the ham or leg.
- Look for a small loose bone
that would fill a cupped hand. This is the patella of the hind limb.
- Look for the stump of the
tail, with its small, simple caudal vertebrae.
- Look for a series of small
round sections of white cartilages. These are the costal cartilages
plate, flank, belly or breast.
- Look for groups of several
small muscles, each surrounded by white fibrous tissue. These are the
and flexor muscles from the distal part of a limb. The Achilles tendon
indicates the hind limb.
Meat cuts from many countries and in many languages are available in:
Swatland, H.J. (2004). Meat Cuts and
Muscle Foods. Nottingham University Press, Nottingham.