Rapid chilling has no detrimental effect on the tenderness of low-voltage electrically stimulated M. longissimus in Chinese bulls

This study investigated the effect of pre-rigor rapid chilling (RC) on the rate of pH and temperature decline, shear force values and ultrastructure of M. longissimus from beef carcasses exposed to electrical stimulation (ES). Chinese bull carcasses were electrically stimulated, and the alternate sides of the carcasses either were chilled conventionally (CC, 0-4 °C, air speed 0.5 m/s for 24 h) or they underwent RC (− 14 ± 1 °C, air speed 3 m/s for 2 h and then cooled under CC conditions until 24 h post-mortem). The results showed that RC increased the rate of temperature decline (P < 0.05) and decreased the rate of pH decline (P < 0.05). There were no significant differences in the shear force value and sarcomere length of M. longissimus between the two treatments (P > 0.05). The results of this study indicate that RC has no detrimental impact on the tenderness of beef carcasses exposed to ES.