Welcome to the Wonderful World of Meat!

1. Welcome to the Wonderful World of Meat! Compiled by Justin Wiebers, Extension Agent, 4-H, University of Tennessee Agricultural Extension Service

2. Quality Grades • Quality grades reflect the flavor and tenderness of meat and are primarily determined from carcass maturity and the amount of fat within the meat (i.e. marbling or intramuscular fat).

3. USDA Quality Grades for Beef • USDA Prime • USDA Choice • USDA Select • USDA Standard • USDA Commercial • USDA Utility • USDA Cutter • USDA Canner

4. Official USDA Marbling Photos Moderately Abundant Slightly Abundant Moderate Modest Small Slight

5. Official USDA Marbling Photos USDA Prime: Prime grade beef is the ultimate in tenderness, juiciness, and flavor. It has abundant marbling -- flecks of fat within the lean -- which enhances both flavor and juiciness. Prime roasts and steaks are unexcelled for dry-heat cooking (roasting and broiling)

6. Official USDA Marbling Photos

7. Official USDA Marbling Photos USDA Choice: Choice grade beef has less marbling than Prime, but is of very high quality. Choice roasts and steaks from the loin and rib will be very tender, juicy, and flavorful and are, like Prime, suited to dry-heat cooking. Many of the less tender cuts, such as those from the rump, round, and blade chuck, can also be cooked with dry heat.

8. Official USDA Marbling Photos

9. Official USDA Marbling Photos USDA Select: Select grade beef is very uniform in quality and somewhat 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. Only the tender cuts should be cooked with dry heat. Other cuts should be marinated before cooking or cooked with moisture to obtain maximum tenderness and flavor.

10. Official USDA Marbling Photos Standard and Commercial: This grade ofbeef frequently is sold as ungraded or as "brand name" meat. The three lower grades -- USDA Utility, Cutter, and Canner -- are seldom, if ever, sold at retail but are used instead to make ground beef and manufactured meat items such as frankfurters

11. Maturity The age of a beef animal has a direct effect on tenderness of the meat it produces.  As cattle mature, their meat becomes progressively tougher. To account for the effects of the maturing process on beef tenderness, evaluations of carcass maturity are used in determining USDA Quality Grades.  There are five maturity groupings, Designated as A through E below. Approximate ages corresponding to each maturity classification are:A - 9 to 30 Months B - 30 to 42 Months C - 42 to 72 Months D - 72 to 96 Months E - More Than 96 Months

12. Official USDA Quality Grades

13. USDA Beef Quality Grades

14. Yield Grades USDA yield grades identify the "quantity" or "cutability" differences among carcasses. Yield grades are 1, 2, 3, 4 and 5, and are a numerical representation of the expected percentage of closely trimmed, boneless retail cuts from the round, loin, rib and chuck. This percentage of retail cuts is the carcass cutability % Boneless, Closely Trimmed Retail Cut Yield Grade From the Round, Loin, Rib and Chuck 1 52.6 - 54.6 2 50.3 - 52.3 3 48.0 - 50.0 4 45.7 - 47.7 5 43.3 - 45.4

15. Yield Grades • Carcass factors used to calculate yield grade • Adjusted fat thickness • Percentage of Kidney, Pelvic and Heart Fat (KPH) • Rib Eye Area • Hot Carcass Weight

16. Adjusted Fat Thickness External fat is measured at the 12th rib perpendicular to the outside fat at a point 3/4 the length of the rib eye (longissimus) muscle. This measurement may be adjusted by the grader to reflect unusual fat distribution in the carcass. Special attention is given to fat deposition in the cod or udder, rump, inside round, flank, lower rib, plate and brisket areas. External fat is the most important yield grade factor. As external fat increases, the percentage of retail cuts decreases.

17. Percentage of Kidney, Pelvic and Heart Fat This is a subjective estimate of the amount of fat surrounding the kidney knob, and fat in the pelvic and thoracic (heart) areas as a percentage of the carcass weight. As the percentage of KPH fat increases, the percentage of retail cuts decreases. Percentage KPH fat normally ranges from 1.0 to 4.0 percent.

18. Rib Eye Area The longissimus muscle is measured at the 12th rib by using a grid expressed in square inches, or a compensating polar planimeter, which measures a rib eye tracing. Rib eye area is an indicator of carcass muscling; as rib eye area increases, retail cut yield increases.

19. Hot Carcass Weight Generally, as carcass weight increases, the percentage of retail cuts decreases slightly due to increased fat deposits. If only chilled carcass weight is available, it can be adjusted to hot carcass weight by multiplying by 1.02 to correct for the evaporative weight loss of the carcass in the cooler.

20. Calculating Yield Grade Yield grades are calculated by using the following formula: YG = 2.50 + (2.50 × Adjusted Fat Thickness, inches) + (0.20 × Kidney, Pelvic and Heart Fat %) + (0.0038 × Hot Carcass Weight, lb) - (0.32 × Rib eye area, sq. in.)

21. Calculating Yield Grade For example, a carcass has 0.40 inch of fat, 2.5 percent KPH, 12.8 sq. inches of rib eye and a hot carcass weight of 750 lbs. Substitute these variables into the yield grade equation to calculate a final yield grade of 2.75: YG = 2.50 + (2.50 × 0.4 in.) + (0.20 × 2.5 percent) + (0.0038 × 750 lbs.) - (0.32 × 12.8 sq. in.) YG = 2.75