Cold-shortening toughness in excised pork M. Longissimus dorsi.

Excised pork M. Longissimus dorsi from six Large White Cross pigs were subjected to a range of chilling rates using temperatures between 20°C and -20°C. Onset of rigor at 20°C varied from 3 to 7.5 h between animals and rigor was complete in 6.5 to 15 h. Cold-shortening was induced when samples were chilled in air or liquid at 3°C or below but not at 5°C or ambient. The highest cooling rate, using liquid at -1°C, reduced the meat samples to 10°C in about 1 h and induced 34% shortening. After ageing for 5 days at 3°C in 26 h. Considering all chilling rates, toughness increased as the time to reach 10°C decreased to 3 h or less. Extensive cold-toughening would be unlikely to occur in current UK commerce and any toughening which did occur would be confined to Longissimus dorsi M. in about 20% of carcasses. The projected increased introduction of very rapid cooling, particularly in conjunction with lean pig production and hot deboning of pork, could toughen all cuts in about 60% of carcasses.