Influence of Fat Thickness, Marbling and Length of Aging on Beef Palatability and Shelf-life Characteristics

Carcasses from 60 Hereford and Hereford-Angus cross steers and heifers were selected for one of four categories: >1.52 cm fat thickness-modest or above marbling, <1.02 cm fat thickness-modest or above marbling, <1.52 cm fat thickness-slight or below marbling, <1.02 cm fat thickness-slight or below marbling. One strip loin from each carcass was aged under vacuum for 10 days at 2 C, while the opposite strip loin was aged for 20 days. Regardless of the amount of external fat, loin steaks possessing modest or above marbling had lower shear values, and higher tenderness and juiciness ratings than steaks containing slight or lower marbling, although mean palatability scores were in the acceptable range for both palatability traits. Twenty days of aging produced lower shear force measurements than 10 days of aging. Carcass characteristics and measurements were low in their relationships to tenderness attributes with marbling scores having the highest correlations. Within the various selection categories, increases in marbling over the range included in the study or above modest were associated with improvements in tenderness, while the opposite was true for marbling scores of slight or below. Twenty days of aging resulted in greater off-odor, more extensive fat discoloration and higher bacterial counts than 10 days of vacuum packaged aging. Differences in subcutaneous fat and degree of marbling did not influence shelflife considerations.