A comparison of the effectiveness of earthing methods in a low voltage electrical stimulation unit for beef carcasses

Abstract

Proc. Aust. Soc. Anim. Prod. 1996 Vol. 21 A COMPARISON OF THE EFFECTIVENESS OF EARTHING METHOD IN A LOW VOLTAGE ELECTRICAL STIMULATION UNIT FOR BEEF CARCASSES C.R. STEVENSONA, R.D. WARNER B and B.W. KNEE C * Institute for Integrated Agricultural Development, Rutherglen, Vic. 3685 * Victorian Institute of Animal Science, Werribee, Vic. 3030 'Pastoral and Veterinary Institute, Hamilton, Vic. 3300 Low voltage electrical stimulation (LV-ES) of beef carcasses is recommended to prevent the occurrence of cold-toughening of muscles, thus improving the production of tender meat (Powell et al. 1985). In a comparison of LV-ES systems, CSIRO have previously recommended that an anal probe be used as an earth for effective stimulation to occur. However, incorrect insertion of the anal probe has potential to pierce the rectal wall of the animal, which may result in increased microbial contamination. In 1 Victorian abattoir the incidence of rectal piercing is reported to be as high as 80%. This study aimed to investigate the effectiveness of alternative methods of earthing during low voltage electrical stimulation. Three methods of earthing were used to compare a Koch-Britton Low Voltage Electric Stimulator to an unstimulated control group using 30 carcasses per treatment (total = 120). Stimulation occurred within 5 minutes of slaughter with carcasses subjected to a peak voltage of 45 volts for 40 seconds at a pulse rate of three seconds on/one second off. The pH was measured in duplicate in the muscle Zungissimus dorsi, at 3 hours post-slaughter using a Sentron pH meter. Carcasses were of mixed sex and breeds and ranged from 140-250 kg hot carcase weight. The mean pH for each treatment group is shown below in table 1. Table 1. The mean pH f SE for each treatment group POWELL, V.H., HARRIS, P.V. and SHORTHOSE, W.R. (1986). Food Tech. in Amt. 38: 230-3. 385