Very fast chilling of beef carcasses

To determine if very fast carcass chilling (VFC; approximately -1degreesC within 5 h postmortem) of beef carcasses could be achieved through blast chilling, 96 carcasses of an estimated Canada I grade were used. The right side of each carcass was assigned to blast chilling conditions of either -20degreesC (48 sides) or -35degreesC (48 sides) while the left side was assigned to control chilling conditions (2degreesC for 24 h; 96 sides). Wind speed in the blast chill tunnel was 2.32 in s(-1). Within each blast chill temperature, 12 blast-chilled sides were removed from the tunnel at each of four times (3, 5, 7 or 10 h) and chilled for the remainder of the 24-h period at 2degreesC. VFC conditions were not achieved in the deep hip region under any chilling regime, but were reached in the longissimus thoracis (LT) by approximately 6.5 h under rigorous chilling regimes (7 or 10 h of blast chilling at -35degreesC). After 6 d aging, LT muscles from sides blast chilled at -35degreesC for 10 h were more tender (22.4 vs. 29.3 N cm(-2): P = 0.004) than those from their respective control sides. When these shear forces were categorized into tender (less than or equal to 19.4 N cm(-2)), probably tender (> 19.4 less than or equal to 27.2 N cm-2), probably tough (> 27.2 less than or equal to 33.2 N cm(-2)) and tough (> 33.2 N cm(-2)) categories, there was a higher proportion of tender (25.0 vs. 0.0%) and probably tender (58.33 vs. 33.33%) shears in the -35degreesC blast-chilled sides than in the control sides (P = 0.06). However, these differences disappeared with extended aging to 21 d. Hence, the VFC advantage would be a reduction in the necessary aging time to achieve an acceptable product. The extreme chilling regime also resulted in significant reductions in cooler shrink, a slower rate of pH decline, an increased perception of marbling, darker meat colour and increased drip losses at retail. Further study of the mechanism of VFC tenderization is warranted.