Effects of Early Post-Mortem Rate of pH fall and aging on Tenderness and Water Holding Capacity of Meat from Cull Dairy Holstein-Friesian Cows

Fast or slow muscle pH fall may give unacceptable purge losses or tough meat, depending much on concomitant evolution of muscle temperature early post-mortem, costing millions of euros to the meat industry. Tenderness and purge losses of Longissimus thoracis/lumborum (LTL) and Gluteus medius (Gm) sampled from cull dairy cows differing in production status (10 lactating vs. 22 dried off) and aging time, were evaluated regarding different rates of pH2 fall. Shear force related to pH2 was dependent on muscle and aging time. The intermediate glycolysis led to lower shear force in LTL, while the faster produced best quality in Gm. Purge was influenced by pH2 (P=0.0077), aging (Pu003c0.0001) and muscle*pH2 interaction (Pu003c0.0001). Aging affected thawing (Pu003c0.0001), grilling (P=0.0004) and overall losses (Pu003c0.0001). Under the ruled chilling regime, the fast pH fall in Gm and the slow pH fall in LTL approached out of the ideal pH6/temperature limits, being compatible with heat and cold shortening, respectively.