The influence of ante-mortem treatment on relationship between pH and tenderness of beef.

Longissimus lumborum et thoracis muscles from 150 cattle comprising Czech Pied breed bulls and cows were used to investigate the relationship between pH value and beef tenderness as influenced by housing before slaughter and by the hanging mode of carcasses. The pH value was measured in the loin at the end of the slaughter-line (pH(0)) and after cooling of carcasses (pH(24),pH(48)). The texture of raw meat was measured 72h post-mortem by the Warner-Bratzler shear method; the shear force was related to pH. Curvilinear relationships with coefficients of correlation r=0.64 (P<0.05) for bulls individually housed and r=0.83 for bulls housed in groups between the shear force and the pH value 24h p.m. were found with maximal shear force (the most tough meat) in the range of pH(24) from 6.2 to 6.4. Lower correlations (r=0.72 and r=0.54) between pH(24) and meat tenderness were found in the case of cows individually housed and housed in groups, respectively. No significant relationships were found between texture and pH measured at the end of the slaughter-line (r=0.59 for bulls and r=0.65 for cows) and 48h post-mortem (r=0.64 for bulls and r=0.50 for cows). The mode of housing of cattle before slaughter influenced the properties of beef significantly. Meat of bulls housed in groups before slaughter was less tender (the shear force was higher) than meat of bulls individually housed. It could be explained by higher depletion of glycogen before slaughter and thus insufficient pH decline. Generally, the meat of cows was more tender than of bulls irrespective of housing. No significant differences were found between the left and right halves of carcasses. Thus the mode of hanging had no influence on beef tenderness.