Prerigor carcass muscle stretching effects on tenderness of grain-fed beef under commercial conditions

A prerigor cut was made through the 12th thoracic vertebrae and another skeletal cut through the ischium on the pelvic bone of one side of 16 USDA Choice and 9 USDA Select beef carcasses (TC), while the companion sides served as controls (C) under industry conditions. TC lowered CIE a values and resulted in longer sarcomeres in the longissimus muscle (LM). Compared to the C samples, the LM from TC USDA Choice carcasses were rated 28% higher (more tender) in overall tenderness and treated USDA Select carcasses were 18% higher. Also, variation in tenderness of the LM among animals was reduced by the TC Process. For Gluteus medius and Rectus femoris (RF), the TC samples were also more tender