A comparison of processing characteristics of pre-rigor and post-rigor cow beef

Two Hoi stein cows were slaughtered and divided into pre-rigor and post-rigor processed sides. Salt (NaCl) was added at levels of 0%, 4%, and 8% to test preblending possibilities. Four chilling treatments were conducted upon coarse ground vacuum packaged samples of each salt level for the pre-rigor processed blends. The four chilling treatments included CO₂ snow chill, agitated brine chill, 0°C chill, and -29°C chill. A fifth chilling treatment was the 0°C conventional chill of the side not processed pre-rigor. This treat ment served as a post-rigor control for processing characteristic comparisons.

All salt level and chilling treatment (pre- and post-rigor) combinations were analyzed for fat, moisture, pH, water holding capacity, emulsifying capacity, odor, aerobic psychrophile, mesophile, and lactic acid bacteria counts. Patties from the 0% salt level blends for each chilling treatment were analyzed for cook loss and shear force to test for retail application.

Moisture content, fat content, pH, water holding capacity, and redness increased (P<.05) as salt level increased. Emulsifying capacity was highest at the salt level and lowest at the 0% salt level.

Chilling treatments processed pre-rigor had higher pH and emulsifying capacities than the post-rigor processed control (P<.05). There was no difference (P<.05) in water holding capacity between pre- and post-rigor processed treatments. There were no differences in color, cookloss, or shear force between pre- and post-rigor chilling treatments (P<.05). There was a trend for aerobic, mesophi-lic, psychrophilic, and lactic acid bacteria counts to be lower for the post-rigor chilling treatment than for the four pre-rigor chilling treatments.

Results indicate that pre-rigor cow beef is equal to or superior than post-rigor cow beef for use in preblends containing approximately 4% salt or for use in retail or food service ground beef patties.