Apr. 12, 1999 LUBBOCK - Animal scientists at Texas Tech University are exploring methods that could produce beef at higher standards of quality and consistency. They also are investigating techniques to make beef products safer for consumers.
One subject of study is how to make beef more tender prior to slaughter. Many methods already exist for tenderizing meat during processing. A key factor in tenderness relates to the amount of calcium in an animal's muscle tissue. For that reason, the scientists are exploring the effects of quantities of vitamin D fed to the animals. Vitamin D aids in calcium absorption and retention.
"We did a study last spring in which we looked at various doses of vitamin D fed to the animals ten days before slaughter," said Michael Galyean, Ph.D., Thornton Distinguished Professor of Animal Science, in Texas Tech's animal science and food technology department. "Subsequently, after the animals were slaughtered, we did all the routine tests for grading. We also did shear tests on the steaks to determine tenderness." A shear test is performed with a special blade on a core sample of a piece of meat, and determines how much force is necessary to cut through the sample.
The results of the study were marginal, said Galyean. The basic finding was that tenderness didn't necessarily improve on an average basis. We were able to narrow the variation, or inconsistency, in tenderness from animal to animal, within a given group," Galyean said. "We're taking the ones that are tough and making them more tender, but the ones that already are tender aren't showing much change."
Because of some negative effects that the high doses of vitamin D have on the animals, Galyean says further study is necessary to get the full picture. At around five days of the vitamin injections, most animals cease feeding, according to Galyean. The researchers will work to fine tune the dosage and number of days the vitamin is administered in order to minimize the negative effects.
Galyean expects a much more comprehensive study to begin this summer involving three breeds of cattle that historically generate different tenderness levels of beef. "We'll look at a group of British breed cattle which we expect to be fairly tender, the Brahman cattle which we would expect to be tougher, and then a cross-bred group which we would refer to as Continental, the Charolais and Limousin-types."
All of the cattle will be managed in exactly the same manner and fed identical diets, said Galyean. The only variable will be the dosages and timing of the vitamin D.
Other trials being conducted by Texas Tech food technology researchers deal with growth implants in cattle. Already used industry-wide, the use of growth implants is an accepted practice. These implants usually contain an extremely low level of estrogen or androgen, implanted in the ear of the animal. Studies show health risks to the consumer are virtually non-existent. According to Galyean, "Cattlemen can benefit greatly by using implants because of their amazing effects on the efficiency and rate of weight gain. The implants reduce the number of pounds of feed required for efficient gain, or uses the same amount of feed for a higher rate of gain."
Again, Galyean says his team is trying to regulate the dosage and timing of the implant to minimize the negative effects on tenderness, instances of "dark cutters" or cuts of meat that appear darker in color than normal, and of quality grade. "These types of implants will move an animal from a choice grade down to a select grade, which demands a lower price," explained Galyean.
Regarding beef safety, Galyean said the department has future plans for research on e-coli contamination. "The problem with e-coli contamination is that it's not in the meat. It is in the animal's intestinal tract," explained Galyean. "If the carcass is contaminated with feces or with intestinal contact, that's when the e-coli gets into the meat. It's more of a processing problem."
Galyean said other bacteria could be added to the diet to compete with e-coli, and either eliminate or significantly reduce the instances of e-coli contamination. That study could begin as early as this fall.
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