Very fast chilling of beef carcasses

Abstract

To determine if very fast carcass chilling (VFC; approximately –1°C within 5 h postmortem) of beef carcasses could be achieved through blast chilling, 96 carcasses of an estimated Canada 1 grade were used. The right side of each carcass was assigned to blast chilling conditions of either –20°C (48 sides) or –35°C (48 sides) while the left side was assigned to control chilling conditions (2°C for 24 h; 96 sides). Wind speed in the blast chill tunnel was 2.32 m 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 2°C. 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 –35°C). After 6 d aging, LT muscles from sides blast chilled at –35°C 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 (≤ 19.4 N cm–2), probably tender (> 19.4 ≤ 27.2 N cm–2), probably tough (> 27.2 = 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 –35° C 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. Key words: Beef carcasses, rapid chilling, beef quality, tenderness