Meat quality of bison (Bison bison bison) longissimus thoracis et lumborum following very fast chilling

Very fast chilling (VFC; internal muscle temperature of -1degreesC by 5 h postmortem). was achieved in the longissimus lumborum (LL), but not in the semimembranosus, of lean bison carcasses after only 4 or 6 h of chilling at -35degreesC. Rigorous chilling caused a shift in moisture loss from carcass cooler shrink to retail drip loss. Sides exposed to VFC conditions had darker LL colour at 24 h postmortem; however, the difference did not persist to 6 d. While chilling for 2 h at -35degreesC resulted in an increased shear over conventionally chilled samples, the application of VFC for 4 and 6 h decreased mean shear values and resulted in a slight improvement in tenderness consistency. Sensory evaluation panellists noted marginal, non-significant differences. Factors affecting tenderization were the physical prevention of sarcomere shortening due to surface freezing with increased chilling intensity and a contribution from proteolytic enzyme systems over time postmortem. Very fast chilling is an effective means of reducing carcass chilling time while improving tenderness in the LL of lean bison carcasses.