Evaluation of AIS (Nostril-Rectal) extra low voltage electrical stimulation system

Summary

It was demonstrated in 1976 that electrical stimulation (ES) of pre-rigor muscle accelerates glycolytic activity and avoids the increase in toughness normally associated with rapid chilling to below 10C.

Since that time, multiple programs of work have been done to establish practical factors such as optimum voltage and frequency and to study more fundamental questions related to the mechanism by which ES works. Australia first implemented a rectal stimulator on beef carcases in 1978.

An improved model – AIS ‘Tender-pulse’ – was introduced in 1981 and uses a nostril-rectal current pathway. This system conforms to the Australian ‘extra low voltage (ELV)’ regulations and this project sets about completing its required evaluation before going into commercial use.

Objectives

The project evaluated the AIS (Nasal-rectal) electrical stimulation system in a commercial processing setting and examined the effectiveness of this system at improving the tenderness of meat compared to non-stimulated meat which had been tenderstretch.

Key findings

The AIS nostril-rectal electrical stimulation system is effective because:

• under chilling conditions where, without stimulation, considerable toughening occurs, ES significantly lowers shear force values 
• stimulation results in shear force values which are not significantly different from those obtained for meat from unstimulated tender stretched carcases.

By comparing the tenderness of ES meat with that from tenderstretch as well as untreated carcasses, it is possible not only to determine if an ES system will work, but also how well it performs.

Benefits to industry

The benefit of these stimulation systems is that they hasten the process of rigor mortis by causing muscles to undergo work via anaerobic glycolysis, resulting in an initial pH fall followed by a change in the rate of pH decline. Lower pH results in better eating quality and a lower incidence of dark cutting, improving the profitability of red meat processors and improving consumer satisfaction through better eating quality.

MLA action

MLA has continued to investigate the benefits of tender stretching and electrical stimulation over the following decades. In 2008, a report was prepared (A.MQT.0025) examining the physiological understanding of new generation post slaughter electrical technologies which provided an in depth evaluation of all associated technologies up until that point.

Related MLA projects

V.EQT.1407; A.MQT.0044; P.PIP.0239; P.PIP.0240; P.PIP.0246; P.PIP.0252; P.PSH.0252; P.PSH.0270; P.PIP.0142; A.SCT.0014; P.PSH.0231; P.PSH.0221; A.PNT.0052; A.PNT.0050; P.COM.0120; A.MQT.0025

Future research

As it was found that stimulation results in shear force values not significantly different from unstimulated tender stretched carcases, it is suggested further research be conducted into the possible eating quality benefits of a combined electrical stimulation tender stretched system.