History of the discovery of the use of electrical stimulation to improve beef quality-indicating characteristics

Jeffrey W. Savell
Regents Professor and E.M. “Manny” Rosenthal Chairholder
Department of Animal Science
Texas A&M University
College Station, TX 77843-2471

The discovery that the postmortem application of electrical stimulation to beef carcasses resulted in improvements in quality-indicating characteristics of the lean was truly a moment of serendipity. In the spring of 1977, eight steers from the Houston Livestock Show and Rodeo were slaughtered at the Meat Laboratory at Texas A&M University as part of the teaching program. Because carcass information was being collected by Dr. Frank A. Orts, extension meat specialist at Texas A&M University, from as many of the steers as possible as they were being slaughtered in Houston-area processing facilities as part of the show’s carcass contest, Dr. Orts was scheduled to collect this information on these eight carcasses the day following slaughter.

Because I was unsure about how the electrical stimulation process would impact the characteristics of these carcasses and because there was some limited prize money associated with how these carcasses placed in this contest, I decided to apply the electrical stimulation to the right sides of each carcass because most right-handed people naturally would rib the left sides (it is easier to grasp the chine bones of the left carcass side with the left hand so that the right hand can be used to saw the vertebra and to rib the carcass). What I failed to know at the time was that Dr. Orts was left handed so when I came into the cooler the next day to look at the carcasses, I found that he already had been there to collect the data and had ribbed the right sides, which for a left-handed person would be easier to rib by grasping the chine bones with the right hand to allow for sawing and ribbing with the left hand. I was stunned that my plan to allow the non-electrically stimulated sides to be the sides that were evaluated for the carcass contest had failed, and now I wanted to rib the left sides quickly so I could make sure that the exhibitors would not be impacted by having the results based on the electrically stimulated rather than the non-electrically stimulated sides. I quickly ribbed the left sides and began to evaluate the differences between the two sides. I knew it would take some time for the freshly ribbed sides to “bloom” (oxygenation of the myoglobin) so I went back to my office for a brief time to wait for this bloom time to occur.

After a short time period, when I went back in the cooler to look at the carcasses, I noticed that the ribeyes from the two sides were still quite different in appearance:  the electrically stimulated sides were bright red in color with a uniform surface with marbling that was very evident to evaluate, whereas the non-electrically stimulated sides were darker in lean color with a non-uniform surface (especially near the subcutaneous fat) and with marbling that was less evident. At this point, I went to Dr. Gary C. Smith’s office to ask him to come to the cooler with me (Dr. Smith was one of the co-chairs of my Ph.D. committee). He looked at the differences between the two sides and agreed with me that there was something going on with the process of electrical stimulation to cause the electrically stimulated sides to have improved color and firmness of the lean along with marbling that was either in slightly greater quantity or was easier to evaluate. Dr. Smith began to evaluate and record the quality factors for both sides of these carcasses, which based on his impressions of these differences, would be part of his presentation for the upcoming Meat Industry Research Conference program where he had been invited to speak (Smith et al., 1977). Once Dr. Smith revealed to the audience at this conference that there were possible quality-indicating characteristic improvements for electrically stimulated beef (which could translate to USDA quality grade improvements and resulting increases in beef carcass value), the demand for actual in-plant demonstrations greatly escalated along with the true start of the implementation of electrical stimulation in the United States (Stiffler et al., 1982; Savell, 1985).

In the late 1970s, with the increased interest in implementing electrical stimulation in beef processing facilities, especially because of the possibility of improving the quality-indicating/USDA quality grading characteristics of beef carcasses, leaders in the USDA’s Meat Grading Branch were concerned that electrical stimulation may be artificially improving the marbling/color/firmness attributes beyond what the inherent grading ability of the carcass should be.  As a way to better understand this, we conducted a study (Calkins et al., 1980) designed to better address this concern. In the industry, it was well known that beef carcasses that were chilled over the weekend — cattle that were slaughtered on Friday or Saturday and were graded on Monday — had the highest percentage of U.S. Choice and U.S. Prime of any day in the week. Thus, the term, “weekend cattle,” was used to describe the phenomenon of the highest carcass grades being received on Mondays. It appeared that this was exactly what was happening with electrical stimulation:  carcasses that were electrically stimulated and were graded after a 24-hour chill were comparable in quality grade factors to those that had been graded after a 48-hour chill (Calkins et al., 1980), and the great advantage of electrical stimulation in improving quality grade factors was for those carcasses that were chilled and graded at less than or equal to 24 hours postmortem.

It is important to understand the pressures on throughput and space limitations that beef processors at this time faced (it should be noted that even today’s modern beef processors still face throughput and space limitations so some things never change). Before slaughter could begin, the hot box had to have room in it for the hot carcasses to enter. In some processing plants, this may have meant that all of the chilled carcasses were removed from the hot box and were taken to the sales cooler where they would have been ribbed and graded either on the chain (moving past the grader who was on a well-lit stand) or where they were placed on stationary rails where the grader would have walked by and applied the grade stamp to them. The graded carcasses would have been identified for further merchandising and marketing and would have been either shipped out in carcass form to customers who could handle such entities or would have been fabricated into some early form of vacuum packaged boxed beef or at least into some form of hanging primals (chucks, ribs, loins, rounds). At the end of the day, the sales cooler would have been emptied and ready to begin the process again the next day with the transfer of chilled carcasses from the previous day’s slaughter. The need to ready the hot box so that the slaughter floor could begin production forced, at times, short chill times (sometimes as brief as 14 hours for those cattle slaughtered at the end of the day) so that the hot box had room to start that day’s slaughter. Electrical stimulation was especially effective in minimizing quality issues for those carcasses not sufficiently chilled, in time or temperature, before being presented for grading.

Literature Cited

Calkins, C. R., J. W. Savell, G. C. Smith, and C. E. Murphey. 1980. Quality-indicating characteristics of beef muscle as affected by electrical stimulation and postmortem chilling time. J. Food Sci. 45: 1330-1332.

Savell, J. W. 1985. Industrial applications of electrical stimulation. A. M. Pearson and T. R. Dutson, editors, Advances in Meat Research: Volume 1 – Electrical Stimulation. AVI Publishing Company, Inc., Westport, CT. p. Pages 219-236.

Smith, G. C., T. R. Dutson, Z. L. Carpenter, and R. L. Hostetler. 1977. Using electrical stimulation to tenderize meat.  In: Proc. Meat Ind. Res. Conf., Chicago, IL. American Meat Institute Foundation, Arlington, VA. Pages 147-155.

Stiffler, D. M., J. W. Savell, G. C. Smith, T. R. Dutson, and Z. L. Carpenter. 1982. Electrical Stimulation:  Purpose, Application and Results. Texas Agric. Ext. Serv. B-1375, Texas A&M Univ., College Station.

Published November 17, 2013

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