Scientists Take Guesswork Out of Assessing Beef Tenderness

CLAY CENTER, Neb., Nov. 16—Beef carcasses that will yield steaks with above- average tenderness can be identified with about 94 percent accuracy using a testing system developed by Agricultural Research Service scientists.

“The new system will enable meat packers to accurately sort carcasses and market them at prices commensurate with their tenderness,” said ARS Administrator Floyd Horn. ARS is the U.S. Department of Agriculture’s chief scientific research agency.

Until now a savvy supermarket shopper’s best chance of getting a steak that would cook up tender and tasty was to pick one well marbled with tiny flecks of fat. But the scientists, at the Roman L. Hruska U.S. Meat Animal Research Center (MARC) in Clay Center, found that marbling accounts for only about 10 percent of variation in beef ribeye tenderness.

In market research at several retail grocery stores in Kansas, MARC scientists and their collaborators learned just how much people crave a scrumptious steak. The researchers found that 51 percent of consumers were willing to pay an average of $1.84 more per pound for a steak that had been rated as tender.

Under the MARC classification system, a ribeye steak is taken from a chilled carcass, trimmed and cooked. Then a sample is sheared and measured for tenderness with an electronic testing machine that supplies data to a computer. A computerized image analysis of the 1-inch thick ribeye provides an estimate of how many pounds of retail beef the carcass will yield after bones are removed and fat is trimmed.

At least five meat processing companies are considering adopting the system. Small and mid-sized beef packers could easily adapt this technology to their normal operations, says ARS animal physiologist Mohammad Koohmaraie, who heads the MARC Meats Research Unit. Further automation would allow high volume operators to sort up to 400 carcasses per hour without interfering with standard carcass processing rates.

While the MARC system may make pricing more rational as beef moves from packing plants to supermarkets, it could also improve marketing efficiency and production back down on the farm, Koohmaraie says. Live animals with tags or some other form of identification can be matched with data from the computerized image analysis. The information can be conveyed to feedlot managers, helping them better master efficient ways to produce quality beef that’s not overly fat. And cattle breeders can use the information to improve the genetics of their herds.

“We’ve found that about 30 percent of the variation in beef ribeye tenderness can be ascribed to heredity, which may involve expression of many genes,” says Koohmaraie. Because each gene’s contribution is minor compared to environmental factors, identifying gene combinations that produce tenderness would have been nearly impossible when researchers conducted only classical inheritance studies. But now MARC scientists are refining the cattle genome map to make the task doable.

An article about the research appears in the November issue of ARS' Agricultural Research magazine, which can be found on the web at:

http://www.ars.usda.gov/is/AR/archive/nov99/beef1199.htm

The market research on tenderness was partly funded by public and private grants obtained through the Research Institute on Livestock Pricing at Virginia Polytechnic Institute and State University at Blacksburg, Va. Details on the consumer preferences can be accessed from:

http://www.aaec.vt.edu/rilp/publications.html

Scientific contact: Mohammad Koohmaraie, ARS Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, Neb., phone (402) 762-4222, fax (402) 762-4149, koohmaraie@email.marc.usda.gov.