Identification of animal tissue in meat products by means of PCR

Based on suitable DNA sequences of mitochondrial and nuclear genes a limit of detection of less than 0.01% with respect to the meat content was determined using mitochondrial gene sequences. In contrast to the mitochondrial target sequences the use of nuclear gene fragments leads to a limit of detection of animal tissue which is 100 to 1000 fold higher. This fact influences the method to be applied for DNA based animal species identification. DNA based methods using mitochondrial sequences are appropriate for animal tissue with only a low nucleic acid content or highly processed products with a poor DNA quality. On the other hand methods based on nuclear DNA proved to be more applicable for semiquantitative determination of the meat content in processed products. Furthermore false positive PCR results caused by process dependant contaminations are normally not detected if nuclear gene sequences are used for PCR analysis as their limit of detection is about 1%.