Effect of different types and locations of the electrode source of an extra low voltage electrical stimulation system...

An extra low voltage (45V) electrical stimulation (ES) system was used to determine the effects of using different types and locations of the positive electrode and negative ground of the ES system on beef carcass quality. Thirty-three Angus heifers (22 months of age) were assigned at slaughter to one of six ES treatments (trt): (1) rectal probe with a ground inserted in the incision made below the brisket during exsanguination, (2) rectal probe with ground inserted in the neck above the atlas joint, (3) rectal probe with a ground attached to the lower mandible, (4) muzzle clamp with a ground inserted in the shackled leg, (5) nasal clamp with a ground inserted in the shackled leg and (6) non-stimulated controls. Stimulation was generated using a full wave rectified pulsating direct current of 16 Hz for a duration of 90s within 3 min of exsanguination. Carcasses were chilled at 2°C and evaluated at 24h post mortem. Regardless of type or where the electrodes were placed within the carcass, all ES trt produced a more rapid drop in pH than the control group. Differences in the effectiveness of the various ES trt on improving meat tenderness were observed. For four selected muscles of the carcass (longissimus, semimembranosus, biceps femoris and triceps brachii) the most consistent and uniform improvement in tenderness was found using ES trt 1 or trt 3. The only drawback associated with trt 1 was the ineffectiveness in eliminating the formation of heat-ring. The other ES trt were successful in alleviating this problem. This study indicates that type and locations of electrode source in an extra voltage ES system are important factors to consider in developing an efficacious low voltage ES system. This work also suggests successful implementation of extra low voltage carcass ES for commercial use if specific types of rectal probe electrode systems are used.