*Maturity increases from left to right (A through E) Represents midpoint of Prime and Commercial grades.

Figure 1

lean associated with "dark cutting beef" is present in varying degrees from that which is barely evident to so-called "black cutters" in which the lean is actually nearly black in color and usually has a "gummy" texture. Although there is little or no evidence which indicates that the "dark cutting” condition has any adverse effect on palatability, it is considered in grading because of its effect on acceptability and value. Dependent upon the degree to which this characteristic is developed, the final grade of carcasses which otherwise would qualify for the Prime, Choice, or Good grades may be reduced as much as one full grade. In beef otherwise eligible for the Standard or Commercial grade, the final grade may be reduced as much as one-half of a grade. In the Utility, Cutter, and Canner grades, this condition is not considered.

(t) The cutability group of a beef carcass is determined by considering four characteristics: (1) The amount of external fat, (2) the amount of kidney, pelvic, and heart fat, (3) the area of the ribeye muscle, and (4) the carcass weight.

(u) The amount of external fat on a carcass is evaluated in terms of the thickness of this fat over the ribeye muscle measured perpendicular to the outside surface at a point three-fourths of the length of the ribeye from its chine bone end. This measurement may be adjusted, as necessary, to reflect unusual amounts of fat on other parts of the carcass. In determining the amount of this adjustment, if any, particular attention is given to the amount of fat in such areas as the brisket, plate, flank, cod or udder, inside round, rump, and hips in relation to the actual thickness of fat over the ribeye. Thus, in a carcass which is fatter over other areas than is indicated by the fat measurement over the ribeye, the measurement is adjusted upward. Conversely, in a carcass which has less fat over the other areas than is indicated by the fat measurement over the ribeye, the measurement is adjusted downward. In many carcasses no such adjustment is necessary; however, an adjustment in the thickness of fat measurement of one-tenth or two-tenths of an inch is not uncommon. In some carcasses a greater adjustment may be necessary. As the amount of external fat increases, the percent of retail cuts

decreases each one-tenth inch change in adjusted fat thickness over the ribeye changes the cutability group by 25 percent of a cutability group.

(v) The amount of kidney, pelvic, and heart fat considered in determining the cutability group includes the kidney knob (kidney and surrounding fat), the lumbar and pelvic fat in the loin and round, and the heart fat in the chuck and brisket area which are removed in making closely trimmed retail cuts. The amount of these fats is evaluated subjectively and expressed as a percent of the carcass weight. As the amount of kidney, pelvic, and heart fat increases, the percent of retail cuts decreases-a change of 1 percent of the carcass weight in these fats changes the cutability group by 20 percent of a cutability group.

(w) The area of the ribeye is determined where this muscle is exposed by ribbing. This area usually is estimated subjectively; however, it may be measured. Area of ribeye measurements may be made by means of a grid calibrated in tenths of a square inch or by other devices designated by AMS. An increase in the area of ribeye increases the percent of retail cuts-a change of 1 square inch in area or ribeye changes the cutability group by approximately 30 percent of a cutability group.

(x) Hot carcass weight (or chilled carcass weight x 102 percent) is used in determining the cutability group. As carcass weight increases, the percent of retail cuts decreases-a change of 100 pounds in hot carcass weight changes the cutability group by approximately 40 percent of a cutability group.

(y) The standards include a mathematical equation for determining cutability group. This group is expressed as a whole number; any fractional part of a designation is always dropped. For example, if the computation results in a designation of 3.9, the final cutability group is 3-it is not rounded to 4.

(z) The cutability standards for each of the first four cutability groups list characteristics of two carcasses of two different weights together with descriptions of the usual fat deposition pattern on various areas of the carcass. These descriptions are not specific requirements-they are included only as illustrations of carcasses which are near the borderlines between groups. For

example, the characteristics listed for cutability group 1 represent carcasses which are near the borderline of cutability groups 1 and 2. These descriptions facilitate the subjective determination of the cutability group without making detailed measurements and computations. The cutability group for most beef carcasses can be determined accurately on the basis of a visual appraisal.

[30 F.R. 4456, Apr. 7, 1965]

§ 53.103 Specifications for official United States standards for grades of carcass beef (cutability).

(a) The cutability group of a beef carcass is determined on the basis of the following equation: Cutability group2.50+(2.50 x adjusted fat thickness, inches)+(0.20 x percent kidney, pelvic, and heart fat)+(0.0038 x hot carcass weight, pounds)-(0.32 x area ribeye, square inches).

(b) (1) The cutability group of a hindquarter, forequarter, or cut eligible for grading also is determined on the basis of the above equation in which the hot carcass weight is determined by multiplying the chilled weight of the cut by an appropriate factor as applicable to the cut and its style of preparation.

(2) The factors shown below shall be applicable to hindquarters and forequarters produced by ribbing as described herein, and to ribs, trimmed full loins, and trimmed short loins which are trimmed as described in Items 103, 172, and 173, respectively, of the Institutional Meat Purchase (IMP) Specifications for Fresh Beef-Series 100, as revised October 1961.

(5) For untrimmed hindquarters and for untrimmed hindquarter cuts, the quantity of kidney and pelvic fat is estimated as a percent of the hot side weight.

(c) The following descriptions provide a guide to the characteristics of carcasses in each cutability group to aid in determining cutability groups subjectively.

(1) Cutability Group 1. (i) A carcass in cutability group 1 usually has only a thin layer of external fat over the ribs, loins, rumps, and clods and slight deposits of fat in the flanks and cod or udder. There is usually a very thin layer of fat over the outside of the rounds and over the tops of the shoulders and necks. Muscles are usually visible through the fat in many areas of the

carcass.

(ii) A 500-pound carcass of this group which is near the borderline of cutability groups 1 and 2 might have three-tenths inch of fat over the ribeye, 11.5 square inches of ribeye, and 2.5 percent of its weight in kidney, pelvic, and heart fat.

(iii) An 800-pound carcass of this group which is near the borderline of cutability groups 1 and 2 might have four-tenths inch of fat over the ribeye, 16.0 square inches of ribeye, and 2.5 percent of its weight in kidney, pelvic, and heart fat.

(2) Cutability Group 2. (1) A carcass in cutability group 2 usually is nearly completely covered with fat but the lean is plainly visible through the fat over the outside of the rounds, the tops of shoulders, and the necks. There usually is a slightly thin layer of fat over the loins, ribs, and inside rounds and the fat over the rumps, hips, and clods usually

is slightly thick. There are usually small deposits of fat in the flanks and cod or udder.

(ii) A 500-pound carcass of this group which is near the borderline of cutability groups 2 and 3 might have five-tenths inch of fat over the ribeye, 10.5 square inches of ribeye, and 3.5 percent of its weight in kidney, pelvic, and heart fat.

(iii) An 800-pound carcass of this group which is near the borderline of cutability groups 2 and 3 might have six-tenths inch of fat over the ribeye, 15.0 square inches of ribeye, and 3.5 per~ cent of its weight in kidney, pelvic, and heart fat.

(3) Cutability Group 3. (i) A carcass in cutability group 3 usually is completely covered with fat and the lean usually is visible through the fat only on the necks and the lower part of the outside of the rounds. There usually is a slightly thick layer of fat over the loins, ribs, and inside rounds and the fat over the rumps, hips, and clods usually is moderately thick. There usually are slightly large deposits of fat in the flanks and cod or udder.

(ii) A 500-pound carcass of this group which is near the borderline of cutability groups 3 and 4 might have seven-tenths inch of fat over the ribeye, 9.5 square inches of ribeye, and 4.0 percent of its weight in kidney, pelvic, and heart fat.

(iii) An 800-pound carcass of this group which is near the borderline of cutability groups 3 and 4 might have eight-tenths inch of fat over the ribeye, 14.0 square inches of ribeye, and 4.5 percent of its weight in kidney, pelvic, and heart fat.

(4) Cutability Group 4. (1) A carcass in cutability group 4 usually is completely covered with fat. The only muscles usually visible are those on the shanks and over the outside of the plates and flanks. There usually is a moderately thick layer of fat over the loins, ribs, and inside rounds and the fat over the rumps, hips, and clods usually is thick. There usually are large deposits of fat in the flanks and cod or udder.

(ii) A 500-pound carcass of this group which is near the borderline of cutability groups 4 and 5 might have one inch of fat over the ribeye, 9.0 square inches of ribeye, and 4.5 percent of its carcass weight in kidney, pelvic, and heart fat.

(iii) A 800-pound carcass of this group which is near the borderline of cutability groups 4 and 5 might have one and one-tenth inch of fat over the ribeye, 13.5 square inches of ribeye, and 5.0 percent of its weight in kidney, pelvic and heart fat.

(5) Cutability Group 5. A carcass in cutability group 5 usually has more fat on all of the various parts, a smaller area of ribeye, and more kidney, pelvic, and heart fat than a carcass in cutability group 4.

[30 F.R. 4459, Apr. 7, 1965]

§ 53.104 Specifications for official United States standards for grades of carcass beef (quality-steer, heifer, cow).

(a) Prime. (1) Carcasses and wholesale cuts with minimum Prime grade conformation are thickly muscled throughout and tend to be very wide and thick in relation to their length. Loins and ribs tend to be thick and full. Rounds tend to be plump and the plumpness carries well down to the hocks. The chucks tend to be thick and the necks and shanks tend to be short.

(2) (i) Minimum quality characteristics are described for two maturity groups which cover the entire range of maturity permitted in the Prime grade.

(ii) Carcasses in the younger group range from the youngest that are eligible for the beef class to those at the juncture of the two maturity groups, which have slightly red and slightly soft chine bones and cartilages on the ends of the thoracic vertebrae that have some evidence of ossification. In addition, the sacral vertebrae are completely fused and the cartilages on the ends of the lumbar vertebrae are nearly completely ossified. The rib bones are slightly wide and slightly flat and the ribeye muscle is light red in color and is fine in texture. The minimum degree of marbling required increases with advancing maturity throughout this group from minimum slightly abundant to maximum slightly abundant (see Figure 1) and the ribeye muscle is moderately firm.

(iii) Carcasses in the older group range from those described above as representative of the juncture of the two groups to those at the maximum maturity permitted in the Prime grade,

which have chine bones tinged with red and cartilages on the ends of the thoracic vertebrae that are partially ossified. In addition, the cut surface of the lean tends to be fine in texture and the carcasses are at least moderately symmetrical and uniform in contour. The minimum degree of marbling required increases with advancing maturity throughout this group from minimum moderately abundant to maximum moderately abundant (see Figure 1) and the ribeye muscle is firm.

(3) A development of quality superior to that specified as minimum for the Prime grade may compensate, without limit, for a development of conformation inferior to that specified as minimum for Prime at an equal rate as indicated in the following example: A carcass which has mid-point Prime quality may have conformation equal to the mid-point of the Choice grade and remain eligible for Prime. However, regardless of the extent to which the conformation of a carcass exceeds the minimum of the grade, a carcass must have minimum Prime quality to be eligible for Prime.

(4) Only beef produced from steers and heifers is eligible for the Prime grade.

(b) Choice. (1) Carcasses and wholesale cuts with minimum Choice grade conformation are moderately thick muscled throughout and tend to be moderately wide and thick in relation to their length. Loins and ribs tend to be moderately thick and full. Rounds tend to be moderately plump. The chucks tend to be moderately thick and the necks and shanks tend to be moderately short.

(2) (i) Minimum quality characteristics are described for two maturity groups which cover the entire range of maturity permitted in the Choice grade.

(ii) Carcasses in the younger group range from the youngest that are eligible for the beef class to those at the juncture of the two maturity groups, which have slightly red and slightly soft chine bones and cartilages on the ends of the thoracic vertebrae that have some evidence of ossification. In addition, the sacral vertebrae are completely fused and the cartilages on the ends of the lumbar vertebrae are nearly completely ossified. The rib bones are slightly wide and slightly flat and the ribeye muscle is moderately light red in color and is fine in texture.

The minimum degree of marbling required increases with advancing maturity throughout this group from a minimum small amount to a maximum small amount (see Figure 1) and the ribeye muscle is slightly soft.

(iii) Carcasses in the older group range from those described above as representative of the juncture of the two groups to those at the maximum maturity permitted in the Choice grade, which have chine bones tinged with red and cartilages on the ends of the thoracic vertebrae that are partially ossified. In addition, the cut surface of the lean tends to be fine in texture and the carcasses are at least moderately symmetrical and uniform in contour. The minimum degree of marbling required increases with advancing maturity throughout this group from a minimum modest amount to a maximum modest amount (see Figure 1) and the ribeye muscle is slightly firm.

(3) A development of quality superior to that specified as minimum for the Choice grade may compensate, without limit, for a development of conformation inferior to that specified as minimum for Choice at an equal rate as indicated in the following example: A carcass which has mid-point Choice quality may have conformation equal to the mid-point of the Good grade and remain eligible for Choice. However, regardless of the extent to which the conformation of a carcass exceeds the minimum of the grade, a carcass must have minimum Choice quality to be eligible for Choice.

(c) Good. (1) Carcasses and wholesale cuts with minimum Good grade conformation are slightly thick muscled throughout and tend to be slightly wide and thick in relation to their length. Loins and ribs tend to be slightly thick and full. Rounds tend to be slightly plump, and necks and shanks tend to be slightly long and thin.

(2) (1) Minimum quality characteristics are described for two maturity groups which cover the entire range of maturity permitted in the Good grade.

(ii) Carcasses in the younger group range from the youngest that are eligible for the beef class to those at the juncture of the two maturity groups, which have slightly red and slightly soft chine bones and cartilages on the ends of the thoracic vertebrae that have some evidence of ossification. In addition, the