The effects of modified carcass chilling on beef carcass grade and quality of several muscles

Abstract

To determine the effect of modified carcass chilling on beef carcass grade and meat quality, paired sides were assigned to modified (5°C for 24 h then 0–2°C until 48 h post-mortem) or control chilling (0–2°C for 24 h). After grading at the completion of respective chilling treatments, the longissimus lumborum (LL), longissimus thoracis (LT), semimembranosus (SM), semitendinosus (ST), and infraspinatus (IS) were removed and evaluated immediately or aged for 7, 15, 21, or 29 d prior to evaluation. Estimated cutability was not affected by chill treatment. Modified chilled sides tended (P = 0.15) to have greater marbling scores than control with ~65% having scores 10–110 units greater than control. In ~15% of paired sides, this difference was sufficient to result in upgrading from Canada AA to Canada AAA. Modified chilling reduced mean shear value across all muscles, with these early effects persisting throughout ageing in the LL and LT and represented a savings of at least 7 d of refrigerated ageing time. Neither modified chilling nor ageing could be relied upon to produce consistently tender meat in the SM and ST. Prior to ageing the IS was the most tender muscle and underwent gradual but significant tenderization during ageing. Since tenderness is the most important meat quality trait, industry adoption of cut specific ageing, combined with modified carcass chilling, would appear to be beneficial to ensure consistent and high-quality beef. Key words: Marbling, ageing, tenderness, beef carcass chilling