Species identification in meat products using quantitative and qualitative PCR techniques, with emphasis on chicken detection

Undeclared adulteration of chicken in processed meat products is commonly reported because of easier and cheaper access. As a result, authenticating techniques should be applied to evaluate their existence in these products. The DNA's higher stability during processing than lipids and proteins makes DNA-based techniques ideal for meat authenticity and traceability. Among these, polymerase chain reaction (PCR) techniques are reliable, highly sensitive, and specific for detecting species origin in foodstuffs. DNA-based methods are divided into two categories including qualitative (species-specific PCR, PCR-RFLP, and DNA barcoding) and quantitative (real-time PCR, droplet-digital PCR, and next-generation sequencing-based DNA metabarcoding) assays. Therefore, the present review intends to critically investigate the principles, advantages, challenges, and advances of PCR techniques, and their practicality for the detection of undeclared chicken in meat products. Among qualitative PCR techniques, capillary and microchip electrophoresis assays could simultaneously detect the animal species with a lower limit of detection than traditional gel electrophoresis. Nevertheless, the detection of undeclared species may occur due to accidental cross-contamination with minute quantities of various meat species during food processing. Quantitative PCR methods, on the other hand, are capable of distinguishing between deliberate and unintentional mislabeling. Additionally, despite the higher cost, NGS-assisted DNA sequencing surpasses other species authentication methods as it can quantitatively identify all target and non-target species using high-quality barcode sequence reference databases. This review could act as a reference guide for researchers, DNA-based technique developers, and regulatory authorities seeking to enhance the global standard protocol for chicken identification in meat products through PCR methodologies.