DXA Measures Meat, Fat Composition in Pork

By Sharon Durham
January 12, 2004

With growing consumer interest in leaner meat, meat packers have looked for technology that efficiently shows how much lean meat or fat is in a commercial cut. That technology may be closer than ever, based on Agricultural Research Service animal scientist Alva Mitchell's work with dual x-ray absorptiometry, or DXA.

In lab tests, DXA images accurately showed the composition of pork carcasses. This procedure, noninvasive and quick, is based on using x-rays of differing energy levels to scan for soft tissue of differing densities, according to Mitchell, at the ARS Growth Biology Laboratory in Beltsville, Md.

The DXA instruments that Mitchell used scanned carcass cross-sections at a speed of 7.68 centimeters per second, compared to the processing chain speed of 16.6 centimeters per second. Mitchell's next step is to find a commercial packing plant to test the technology at commercial speeds.

This new technology would help the industry continue to modernize. U.S. hog production has already undergone significant changes over the last century. In the first half of the 20th century, market hogs were bred for lard that found many uses, including as a resource during both World Wars.

About midway through the century, however, consumers began looking for leaner meat with great nutrition but less fat and fewer calories. The pork industry responded by breeding animals for leanness. The difficulty, however, was in discerning the lean-to-fat ratio throughout a carcass without cutting into it.

Using DXA would allow packers to know just what they are paying for--that is, the true value of the meat, without the fat that gets cut off before shipping.

Read more about this research in the January issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture's chief scientific research agency.