Grade A is 9 to 30 months old; Grade B is 30 to 42 months; Grade C is 42 to 72 months old; Grade d is 72 ~ 96 months old; Grade e for more than 96 months.
Extended data:
According to the quality (represented by marbling) and physiological maturity (age) of beef, beef in the United States is divided into eight grades: superior, selected, selected, standard, commercial, practical, cut and canned.
Marble grain is the main factor that determines the quality of beef, which is closely related to tenderness, juiciness and palatability, and it is also the easiest index to evaluate objectively, so the quality evaluation is represented by marble grain.
Marbling was measured on the cross section of rib eye muscle 12. Based on the standard plate, it is divided into seven grades: rich, medium, moderate, less, less, trace and almost no. When the physiological maturity and marbling are determined, the grade can be judged. The younger the age, the richer the marbles, the higher the grade and the lower the grade.