Tenderness in relation to the temperature of rigor onset in cold shortened beef

Beef sternomandibularis muscle was cold shortened at 2°C for 24 h and then transferred to 37°C until rigor mortis was complete. In spite of a final shortening of 33%, the mean shear value after cooking was identical with that of unshortened meat which had gone into rigor at 15°C. Meat sent into rigor at 2°C with the same degree of shortening had twice the shear value. Thus raising the temperature to 37°C in the final stages of rigor completely nullifies the toughness seen in cold shortened meat, without affecting the shortening. Small changes in cooking loss run parallel to tenderness. The effects are not due to ageing, and may arise from modification of actin–myosin bonding. It is concluded that conditions during the last stages of rigor onset are more important to tenderness than the rest of the post‐mortem history of the muscle.