The Long‐Term Effect of Electrical Stimulation on the Post‐Mortem Fall of pH in the Muscles of Landrace Pigs

SUMMARY It has been shown previously, in a series of experiments on the post‐mortem fall of pH in the muscles of Danish Landrace pigs, that the animals can be broadly divided into two groups, differing in rate of fall. One gives samples with low rates, called A, and the other with rates twice as high, called B. The present experiments show that the slow fall of pH in group A muscles can be converted to a quick fall by subjecting excised samples to a short tetanus. This accelerating effect of electrical stimulation lasts during the whole course of the pH‐time curves, and is easily distinguished from the well‐known short‐term effect, characteristic of this and many other types of muscle. Although the latter can be clearly demonstrated in rabbit muscle, for instance, the subsequent long‐term acceleration is entirely absent. The latter must therefore be considered a new and hitherto undescribed phenomenon, so far reported only for the pig. It is due to an induced higher ATP‐ase activity, although the mechanism is obscure. These findings open up a new approach in the search for the Cause of the rapid postmortem fall of pH characteristic of pig muscles which subsequently yield pale and watery pork.