
Near-Infrared Technology Measures Beef Fat BetterBy Jill Lee March
11, 1998Shining invisible light on a hamburger patty could lead to a safer, cheaper,
faster and more environmentally friendly laboratory method for figuring out how
much saturated fat the burger holds. The Food and Drug Administrationregulates the chemical methods of fat analysis now widely used by the food
industry for quality control in recipes as well as for obtaining fat values
published on all food labels. Health concerns over saturated fats have made this
an important issue with consumers. But the current methods have drawbacks, such as disposal problems posed by
chemicals used in the analysis. Now scientists at the
Agricultural Research Service in Athens,
Ga., are using a non-chemical alternative--a technology called NIR, or
Near-infrared Spectroscopy. Near-infrared light waves are just beyond the
visible part of the light spectrum. To further develop this technology, ARS has entered into a cooperative
research and development agreement with Foss North America of Eden Prairie,
Minn., an international supplier of automated rapid analysis tools for the food
and agriculture industries. Today's chemical method takes two days to yield results. First, technicians
use petroleum ether to extract fat from a food sample. Then they inject a
portion of the fat-ether solution into a gas chromatograph. It separates
saturated from non-saturated fats and calculates their percentages. The
instrument burns the sample used for analysis, but most of the sample left from
the extraction must be disposed of as hazardous waste. The NIR approach can measure fat levels as low as 1 percent, well within FDA
requirements for precision. The approach takes less than two minutes and uses no
ether or other hazardous chemicals. A food sample is exposed to near-infrared
light waves. Saturated fat reflects the NIR wavelengths differently from other
food components, including other fats. A computer measures the sample's
absorbance--the light energy that passes through the sample. It then compares
the data with information from samples with a known fat content. ARS researchers analyzed 302 samples of neck beef to compare speed, accuracy
and convenience of NIR versus traditional chemical analysis. ARS and Foss plan
to develop similar fat analysis techniques for chicken, sausage and pork. They
will also compile a database to include protein and fat data on several meat
items. Scientific contact: William R. Windham, ARS
Quality Assurance
Research Unit, Richard B. Russell Agricultural Research Center, Athens, GA
30605, phone (706) 546-3513, fax (706) 546-3607,
[email protected]. U.S. Department of Agriculture | |