Effect of animal age and trimming practices on the physical composition of Bonsmara beef

• Physical composition of beef changes over time.
• Fat content of marketable beef has decreased over time.
• Trimming significantly reduces lipid content.
• Trimmed beef compares favourably in terms of fat content with other animal products.

Increased economic incentive for producing young and leaner carcasses, as well as demand for lean meat from progressively health conscious consumers, are considered drivers for change in carcass composition over time. Furthermore, many retailers trim visible fat from meat to various degrees and consumers increasingly remove visible fat from meat prior to, or after, cooking.The objective of this study was to determine the composition of South African Bonsmara beef from four age groups from different production systems, as well as to extrapolate the effect of fat trimming on physical composition. Fat content of marketable beef has decreased notably since the 1930s, and beef from the South African Bonsmara breed contains less than 10 g lipid per 100 g after trimming of subcutaneous fat, irrespective of age. Removal of all visible fat reduces the lipid content to less than 5 g per 100 g, comparing favourably with other lean animal products.