Go to any supermarket meat counter in America and there are tons of USDA shields advertising Choice beef. Select beef. And, in some special supermarkets, Prime beef. You've probably seen them and not even given them a second thought. But what exactly do those grades mean? And what difference does it make?
The USDA grades of beef indicate how flavorful, juicy and tender the beef will be according to the quality of the cow carcass. Federal meat grading is a voluntary service that packers request and pay for on an hourly basis on top of mandatory USDA inspections. According to a variety of measures, the USDA separates beef into eight grades of decreasing quality. They are: Prime, Choice, Select, Standard, Commercial, Utility, Cutter and Canner.
Only the top three grades of meat are sold at supermarket meat counters, while the other grades would most likely look too unappetizing to be on display. That’s why they’re used for vienna sausages, grade-school cafeteria hamburgers and other processed meat products you don't want to know too much about. The two main measures of quality that can be seen from shrink-wrapped slabs of cow are marbling and maturity.
Marbling refers to how much fat is located within the lean portion of the beef and is determined by visual evaluation of the rib-eye, the 12th rib cross-section. Beef with more flecks of fat within the muscle are more likely to tender, juicy and flavorful than beef with less marbling. Kobe beef, a delicacy from Kobe, Japan sets the gold standard for marbling. There is so much fat interwoven with the lean beef that the meat ends up tasting buttery and smooth when grilled. Because Prime and Choice beef have more marbling than select, they also have higher fat contents than Select beef. They are also more expensive. Kobe beef in Japan costs upwards of $300 per pound, while some places in the U.S. have started selling it for $30 per pound.
Grades of beef, percentage of intramuscular fat and degrees of marbling
Kobe beef: 20%-25% intramuscular fat
USDA Prime: above 8% intramuscular fat with abundant marbling
USDA Choice: 4%-8% intramuscular fat with small, modest or moderate marbling
USDA Select: 3%-4% intramuscular fat with slight marbling
USDA Standard: below 3% intramuscular fat with traces of marbling
Maturity estimates the age of the beef from bone and lean maturity and has a direct effect on the tenderness of the meat. At the supermarket, maturity can be seen in the lean color of the beef and in the texture of the beef. Meat graders also look at the hardening of cartilage into bone and rib bone shapes to determine the maturity of the beef. The USDA evaluates maturity according to five groupings.
USDA Maturity Ratings
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
Carcasses less than 48 months (A-B) can grade Prime through Standard.
Carcasses more than 48 months (C-E) grade Commercial through Canner.
The protein, vitamin and mineral content of beef are similar regardless of grade. Most ground beef is ungraded, but still inspected for wholesomeness.
Organized grading of beef started in 1923 when the U.S. Shipping Board requested the USDA to grade beef carcasses according to tentative U.S. standards to ensure uniform quality in contract beef purchases. Until then, the Board had problems in routinely procuring beef of the desired quality. Early customers of the voluntary, fee-based grading service were railroads, steamship companies and large hotels. These were followed by hospitals, then ultimately chain stores and retail meat dealers.
Today, federal beef grading serves many functions in the livestock industry. By grading cuts of beef, livestock ranchers can identify and receive prices commensurate with the quality of the livestock they produce, providing consumers, institutions and retailers with a uniform supply of meat of desired quality. By differentiating between different qualities of meat, the industry receives valuable feedback on the demands of consumers so a sufficient supply of beef is available to keep the market competitive and meet consumer needs.
http://www.ianr.unl.edu/pubs/beef/rp357.htm
http://www.2eatcab.com/2eatcab/food/prep/grades.html
http://members.tripod.com/~BayGourmet/wagyu.html
http://www.bovineengineering.com/quality_grades.html
http://www.ams.usda.gov/lsg/mgc/beefrole.htm