Identification of species (meat and blood samples) using nested-PCR analysis of mitochondrial DNA

Crocodile meat product is an alternative protein source. Although, crocodile meat is more expensive, its taste is similar to that of chicken and fish. The authentication of commercial meat species is important for consumer's confidence. In this study, sensitive and specific method multiplex nested-PCR was applied to identify commercial meat species. Dried blood was used as an alternative DNA source for detection. The detection sensitivity was enhanced by primers specifically designed to encompass the mitochondrial Cytochrome b and NADH dehydrogenase 5/6 genes. The specificity and sensitivity of multiplex PCR system were tested. Different lengths of specific nested-PCR products were detected to be 350, 570, 750 and 1000 bp for chicken, pig, cow, and crocodile, respectively. The system allowed detection with as little as 5 nanogram of DNA from either meat or blood sample. Detection sensitivity of individual species was improved, enabling the detection of DNA with as little as 1 picogram. Cross reaction was not detected among the tested species. It was shown that the multiplex-PCR assay enhanced the sensitivity of routine species identification and allowed the use of blood as an alternative DNA source for detection.