The influence of chilling rate and fat cover on beef quality

The economic advantages of rapid carcass chilling include reduced cooling time, increased carcass processing rate, and decreased shrink and drip losses; however, it may also reduce subsequent meat tenderness, especially in lean carcasses. The present study examined the effects of blast chilling and electrical stimulation on quality of longissimus lumborum (LL) and semimembranosus muscles from carcasses with a wide range in backfat thickness (0 to 69 mm). Despite promoting a wide range in postmortem pH and temperature decline, backfat thickness had a limited effect on meat quality. There was a decrease in the proportion of carcasses with very high (> 35 N cm(-2)) shear values and a tendency (P = 0.12) for the average shear force to decrease in the LL as backfat depth increased. Unexpectedly, leaner carcasses had less shrink loss than fatter carcasses under blast chill conditions. While blast chilling resulted in slightly darker, tougher meat, electrical stimulation was able to reduce these effects. Neither early postmortem pH nor temperature at 10 h was clearly associated with a pattern in shear force, although high pH(10) was associated with tough steaks. Blast chilling in combination with electrical stimulation can be recommended to industry as a means to reduce chilling times and shrink losses while producing meat quality that is as good as, or slightly superior to conventionally cooled carcasses.