Post mortem energy metabolism and meat quality of porcine M. longissimus dorsi as influenced by stunning method — A 31P NMR spectroscopic study

Post mortem changes in phosphorus metabolites and pH were studied in M. longissimus dorsi from pigs (n=10) stunned either by CO2 (n=3), electrical (n=2), captive bolt pistol (n=2) or by anesthesia (ketamine) (n=3). 31P-NMR spectroscopy revealed significant effects of stunning method on changes of the various phosphorus metabolites in the muscle post mortem, with the effect being most pronounced on the degradation of phosphocreatine (PCr). Moreover, the four stunning methods gave rise to large differences in the progress of pH as determined by 31P-NMR spectroscopy. Using anesthesia as the reference showed that the captive bolt pistol caused the highest rates of post mortem degradation of phosphorus metabolites, electrical stunning intermediate, and CO2-stunning causing the lowest post mortem degradation rates, even though CO2-stunning also was associated with higher post mortem degradation rates compared with anesthesia. Finally, it was demonstrated that the water-holding capacity (WHC) of the meat was affected by the applied stunning method, as CO2-stunning, electrical stunning and captive bolt pistol resulted in mean drip losses of 6.4, 8.3 and 8.6%, respectively (P=0.02). The result displays the significance of induction and progress in post mortem changes on WHC in meat.