Hamburger lovers beware! The next meat patty you eat may not be what you think it is. But help is on the way. Inspired by a documentary exposing the widespread sale of adulterated ground beef in the US, researchers at the University of Hong Kong have devised a spectroscopy method to detect cheaper meats -- or other materials -- that may be mixed with ground beef and sold as pure beef burgers. The unreported use of fillers, according to the researchers, not only amounts to consumer fraud, but also may pose serious health threats to those allergic to the most common adulterants, such as wheat flour, pork, skim milk powder and mutton. Researchers at the University of Hong Kong are using near-IR spectroscopy to detect unreported fillers in ground beef, including wheat flour, pork, skim milk powder and mutton. The technique identifies adulterants in a matter of minutes, with an accuracy of more than 90 percent. Ruojun J. Xu and H.B. Ding are using a near-IR spectroscopy system from Perstorp Analytical Inc. of Silver Spring, Md., to identify beef hamburger containing between 5 and 25 percent pork, milk powder or wheat flour within a matter of a minutes. The system has an accuracy of 92.7 percent and determines the degree of adulturation with a prediction error of 0.6 to 4.6 percent. Current methods of detecting fillers monitor antibody-antigen reactions. Although such DNA fingerprinting techniques can accurately detect adulterants, these tests can take hours or days. Moreover, their specificity makes the tests too expensive to apply to large-scale screenings. "For each type of adulterant -- pork, chicken or milk protein -- one specific diagnostic test is required," Xu explained. Because the initial study was confined to the laboratory, the system has limited practical value, Xu noted. "The next step is to use commercial hamburger samples with detected adulterants to improve and validate the calibration model," he said. "By then the technique would be ready for commercial testing." Details of the work appeared in the May 20 issue of the Journal of Agriculture and Food Chemistry.