USDA Prime is a grade of beef, as graded in the United States. It is considered the highest grade of domestic beef by the USDA scale, and as such tends to be the most expensive. Beef grade is only one way to label beef, and in recent years there has been a shift from labels such as USDA Prime to labels that designate a particular breed of cattle, a particular style of raising, or a particular locale where the cattle was raised.
The United States Department of Agriculture (USDA) doesn’t require that any meat manufacturers have their beef graded for labeling. It is an entirely voluntary system, and as such tends to only be undertaken in cases where the meat will likely rate fairly high on the scale. Producers who choose to have their meat graded pay for a certified grader to come in and grade entire carcasses, which are then tagged according to their grade. The company can then label the graded meat in a number of ways, including stamping directly on the cuts, a USDA shield, or a label on the container or package itself.
There are eight different grades of meat in the USDA system, with USDA Prime being the highest. They are graded on two different metrics: the maturity of the cattle at slaughter, and the amount of marbling in the meat. Some people have critiqued this system, as it does not actually directly measure the tenderness of the meat, although both of these metrics are generally factors in tenderness. Some groups have suggested an alternative grading that directly measures meat tenderness. Nonetheless, the USDA system is widely appreciated, and similar systems exist in most major beef producing nations.
The USDA Prime carcasses have the absolute highest amount of marbling, or intramuscular fat, of all the carcasses in the United States, and are generally considered to be the best of the best. Directly below USDA Prime is USDA Choice, which is considered a very high quality. Below that is USDA Select, which was previously known as USDA Good, and this type of carcass tends to be fairly lean, and therefore less tender than both USDA Choice and USDA Prime.
Below USDA Select comes USDA Standard, then USDA Commercial, then USDA Utility, Cutter, and Canner. Little of these lower grades actually makes its way into food service, with USDA Select being the most commonly used type of affordable beef. USDA Standard may be used in massive, low-grade kitchens, and USDA Commercial may be used in extremely cheap operations, but the three bottom grades are usually only seen in heavily processed products, never as actual cuts of meat.
The system is fairly exacting, and only around 2% of all carcasses fall into the USDA Prime grade. Because of the cost associated with grading, few carcasses that would fall below USDA Select are ever actually graded, and even USDA Select may often just remain unlabeled. Although USDA Prime continues to have a great deal of name recognition and strength, and many cuts served in gourmet restaurants or nice hotels may be labeled as such, it is beginning to be supplanted by luxury beefs designated by raising style or breed, such as Black Angus or Kobe beef.