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You are here: Home > Journals > AN > EA03257
RESEARCH ARTICLE
Contents Vol 45(5)

New electrical stimulation technologies for sheep carcasses

F. D. Shaw A F , S. R. Baud B , I. Richards C , D. W. Pethick D , P. J. Walker B and J. M. Thompson E
+ Author Affiliations
- Author Affiliations

A Food Science Australia, PO Box 3312, Tingalpa DC, Qld 4173, Australia.

B Department of Primary Industries Victoria, Private Bag 7, Werribee, Vic. 3030, Australia.

C Meat and Livestock Australia, PO Box 3144, South Brisbane, Qld 4101, Australia.

D Murdoch University, Murdoch, WA 6150, Australia.

E University of New England, Armidale, NSW 2351, Australia.

F Corresponding author. Email: fshaw@iinet.net.au

Australian Journal of Experimental Agriculture 45(5) 575-583 https://doi.org/10.1071/EA03257
Submitted: 22 November 2003  Accepted: 12 October 2004   Published: 27 June 2005

Abstract

High voltage electrical stimulation applied to the lamb carcass at the end of the dressing procedure often leads to an improvement in overall product quality by reducing the incidence of toughness. It would be advantageous if the same results could be consistently achieved with the use of lower, safer, voltages — medium voltage electrical stimulation. Experiments were conducted to determine the effect of medium voltage electrical stimulation applied to wool-on carcasses on meat quality as assessed using the Sheep Meat Eating Quality protocols. A further experiment examined the interaction of electrical stimulation and meat aging time on the consumer acceptance of lamb meat. In the first experiment, 3 treatments: control (non-stimulated), medium voltage electrical stimulation (applied to the wool-on carcass) and high voltage electrical stimulation (applied at the completion of dressing) were examined. Samples of the loin (LTL) and rump (GM) muscles were evaluated by consumers using Sheep Meat Eating Quality protocols. For both muscles, the consumers gave higher scores for tenderness, juiciness, flavour and overall acceptability to the stimulated product (P<0.001). There were no statistically significant differences between the 2 stimulation treatments. The second experiment was conducted at a commercial lamb-processing abattoir that had installed a prototype automated electrode system designed to work at chain speed. Lambs received either no stimulation (control), low current medium voltage electrical stimulation (constant current 300 mA peak, 15 Hz, maximum voltage 550 V peak) or high current medium voltage electrical stimulation (constant current 600 mA peak, 15 Hz, maximum voltage 550 V peak) immediately after sticking. Electrical stimulation improved both the objective and sensory (Sheep Meat Eating Quality) eating quality attributes of lamb loin muscle when assessed following 2 days of ageing. When expressed according to consumer satisfaction rating, 30, 37 and 70% of the loins receiving low, high or no electrical stimulation, respectively, were rated as unsatisfactory at 2 days of ageing. At 4 days of ageing no loins from carcasses in the low stimulation treatment were rated by consumers to be unsatisfactory (P<0.05) compared with either non-stimulated (40%) or high-stimulated loins (35%). With respect to the effects of aging meat, electrical stimulation improved the consumer score at 2 days post-stunning by 8.9 and 4.7 points for tenderness and overall liking, respectively. Further linear improvements due to aging were similar for both electrical stimulation and unstimulated products. Under conditions of no electrical stimulation used in this experiment, 10 days aging results in tenderness and overall liking scores greater than 60 and with ES similar scores are achieved in 5 days. Consumer scores over 60 greatly reduce the chance of meat being classified as unsatisfactory.


Acknowledgments

This project relied on the willing assistance of the staff at the Meat Research and Training Centre, VIAS, within the Victorian Government Department of Natural Resources and Environment. We gratefully acknowledge the contribution of Matthew Kerr, Paul Weston and Paul Meredith. The skilled technical assistance and dedication of Mr Malcolm Boyce, Mrs Barbara Waldoch, Mr Ken Chong is gratefully acknowledged. The manager and staff at Hillside Meats are gratefully acknowledged for their enormous cooperation during the slaughter and bone out periods.


Meat and Livestock Australia accepted the muscle samples into their Consumer Sensory Perceptions of Lamb and Sheepmeat Program and provided financial assistance to the project. We thank Alan Gee of Cosign for his assistance with the preparation of the samples for the consumer trials.


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