Pneumatic Measurement of Post-mortem Setting in Pork Carcasses

Abstract

The post-mortem development of firmness in pork carcasses was measured with a pneumatic expansion bulb located deep in the adductor muscle of the ham. The development of rigor mortis in the adductor muscles of similar carcasses was measured with a solenoid-activated tensile rigorometer attached to the carcass. By about 3h post-mortem, rigor mortis was well developed in adductor muscles but resistance to expansion of the pneumatic bulb was essentially unchanged from the initial reading at 45min post-mortem. The temperature deep in adductor muscles at 3h post-mortem was about 23°C. As carcass cooling continued overnight, the firmness of the adductor continued to increase. At 24h post-mortem, expansion of the pneumatic bulb was reduced to 73% of the initial inflation volume at 45min post-mortem. The area of the pressure- displacement curve bounded by the inflation-deflation cycle was reduced to 49% of the initial value. The temperature deep in the adductor at 24h was about 1°C. The setting of pork carcasses to a degree of resilience suitable for traditional pork cutting operations therefore, appears to be mainly a consequence of cooling rather than development of rigor mortis in muscles.