The United States Department of Agriculture (USDA) grades beef for quality. This is different from the mandatory inspection which all meat under goes to insure food safety. Grading is a voluntary process and adds additional expense to manufacturing. As such only the highest quality cattle, those reared specifically for beef production, tend to be graded. The process is conducted by trained USDA meat graders. While the popular notion of the USDA beef grading program is that it is just about the level of fat contained within the ribeye muscle the evaluation is far more complex than just looking at a single data point. It uses the the animal’s physiological maturity, muscle development and fat conformation to arrive at a score. Beef is graded both by yield and by quality, the former is geared towards processors and packers, while the latter is directed at consumers.
Yield grade is determined by evaluating total carcass weight, the quantity of external, kidney, pelvic, and heart fat, and the surface area of the longissumus dorsimuscle. Yield grade is an estimation of the quantity of boneless retail cuts that can be fabricated from the carcass. Yield grade is ranked numerically from one to five with Yield Grade 1 being the most desirable and YG 5 the least. Yield grade information will not be available to consumers, and is not really relevant to them, the quality grade is what determines flavor.
The quality grade is a subjective evaluation. The most well known part of the process is examining the amount of intramuscular fat, the fat that is interspersed within the lean, or muscle, of the meat. This is referred to as marbling. The marbling score is determined at a single location by exposing the longissumus dorsi muscle at the 12th and 13th rib cross section. This is the location of a center cut ribeye and exposing the muscle is known as "ribbing." The grader is looking for the levels of fat flecking in the eye of the ribeye muscle.
More than Marbling
But there is more to grading than just a marbling evaluation. The grader will also look at the levels of skeletal ossification in the cartilage to judge physiological maturity. This is most apparent in the chine bones of the vertebral column. The whiter these “thoracic buttons" of cartilage appear, the younger the animal, and the higher it will grade. A carcass will be graded by the percentage of ossification. Grade A, the highest quality grade, will exhibit less than 10% ossifications and is reserved for animals under 30 months of age. Grade B will exhibit 10 - 35% ossification, reflecting an animal of 30 — 42 months; Grade C is 35 - 70%, 42 - 70 months old, Grade D 70 - 90%, 70 - 96 months old; and finally, Grade E is over 90% and older the 96 months.
The development of the rib bones is examined in determining physiological maturity, with Grade A showing narrow, oval bones, Grade B slightly wide and slightly flat bones, going to completely wide and flat by Grade E. The condition of the bodies of the split chine bone is also evaluated, with Grade A beef being red, porous and soft and becoming progressively whiter, denser, and harder as the animal matures. Finally, the color and texture of the lean meat is evaluated. Grade A cattle have a light cherry red color and very fine texture, Grade B a light cherry to slightly dark red color and fine texture, with the color darkening and the texture becoming coarser as the grades become lower.
The final quality grade is determined by a combination of the overall maturity of the carcass (the combination of skeletal and lean maturity) and the marbling score. There are a total of eight beef grades — Prime, Choice, Select, Standard, Commercial, Utility, Cutter, and last and least, Canner. Prime, Choice, and Select are awarded grading shields and are considered premium products. Prime beef is predominantly sold to the restaurant and hotel trade, and in limited supply to butchers and specialty retailers. Standard grade meat accounts for the bulk of ungraded and economy product. Utility, Cutter, and Canner are used for institutional and processed products and are almost never seen at retail.
In terms of marbling the USDA uses a clearly define nomenclature. The Standard and lower Grade beef is described as practically devoid and “practically devoid to traces (of fat).” Select Grade beef has marbling that is slight, while Choice exhibits small, modest, and moderate levels of marbling. Finally, at the top of the food chain Prime beef has marbling that described as slightly abundant, moderately abundant, and abundant.
...and The Award Goes To
Graded beef will be stamped with a USDA shield bearing the grade and yield score in edible purple ink. USDA Graders are also responsible for certifying Process Verified Programs (PVP) over seen by the USDA. This is for marketing claims such as feeding and breed specific standards. Examples are the Never Ever 3 program (no hormones, no antibiotics, no animal byproducts in the feed) and Certified Black Angus Beef.
While Prime beef has historically accounted for a less than 3% of all graded beef production that number has risen steadily in recent years as better genetics and breeding practices have met market demand. Prime beef accounted for between 4% and 5% of graded beef produced between 2012 and 2016.
You may have seen marketing claiming to offer beef that is “beyond Prime.” Technically there is no such thing as beyond Prime grade as the designation reflects a base threshold of marbling. Beef displaying at least slightly abundant marbling and a carcass maturity grade of B or higher qualifies as Prime.
Why it Matters
The USDA Grading system is intended to make transactions within the meat industry more efficient and to give the consumer a clear indication of quality. A USDA shield represents a base standard in each of its classes and translates in to palatability on the plate. The higher the grade the more tender, juicy, and flavorful the beef is expected to be.