Bovine M. longissimus thoracis meat quality differences due to Canada quality grade.

Differences in meat quality characteristics between the four Canada beef quality grades (Canada Prime, AAA, AA, and A) at days 4 and 18 post mortem were investigated using 48 (n = 12/grade) bovine M. longissimus thoracis (LT, rib eye). There was no difference in intramuscular fat content between Canada A and AA LT, and Canada AA LT had a higher mean Warner-Bratzler shear force (WBSF) than LT from all other grades (P = 0.0009) at day 18 post mortem. Canada Prime muscles were lighter and yellower than muscle from all other grades, and their increased lightness persisted with ageing. Mean cooking loss was lowest in Canada Prime LT and correlated with intramuscular fat content (r = -0.41 and - 0.29, days 4 and 18, respectively). Results confirmed differences in cooked product toughness can exist between the grades, with the potential for reduced tenderization in Canada AA LT.