Apply PCR when checking food species.

In our global food market, regulatory, economic and security issues, including the fraudulent adulteration or mislabeling of food, have been the drivers behind an interest in developing and using reliable tests to determine the authenticity of products in the food supply chain.

Protein-based assays, including isoelectric focusing (IEF) and enzyme-linked immunosorbent assays (ELISAs), are accepted for use in identifying species. But concerns over their specificity, associated test costs and assay complexity have limited their widespread application as a commercial diagnostic platform.

DNA-based testing methods, used on the premise that each species carries unique DNA sequences differentiating it from other organisms, have been powerful tools in the forensic and medical diagnostic arenas. Initial techniques that harnessed DNA for species identification in the food industry have included random amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) assays. But these techniques require several downstream steps that are both time-consuming and labor-intensive, limiting their commercial application.

Scientists in Arkansas have taken a polymerase chain reaction (PCR)-based species identification approach that is simple in format, and which is rapid and reliable for discriminating related species of fresh, frozen and processed meat products. Fundamental to this strategy is the discovery and development of unique markers or groups of markers that characterize the authenticity of meat in mislabeled or blended fish products.

The use of several markers in a PCR reaction in a multiplex format makes it possible to identify several related species in a single test. Researchers anticipate that DNA-based methods will provide a robust platform technology for developing diagnostics in a number of niche food markets that are experiencing issues of fraudulent labeling and species authentication.

Although the U.S. food supply is among the world's safest, the increase in the variety of foods available has brought with it additional public health concerns. The complexity of the food industry and the number of technologies used in production and packaging are increasing, requiring a comparable increase in oversight of the food supply. A growing proportion of food consumed in the United States is not produced domestically but is imported. The rise in imports raises the risk to the food supply because other countries may not maintain the same high standards of production that exist in the United States.

Further information. Maureen Dolan, Arkansas Bioscience Institute, Arkansas State University, 504 University Loop E., Jonesboro, AR 72401; phone: [phone]; email: [e-mail].