A comprehensive review of key requirements and analytical methods for tracking genetically modified (GM) ingredients in processed food products

With the rise in the global market of processed food products, many countries have approved genetically modified (GM) food crops with desired traits. However, the acceptability of these crops for commercial usage varies widely across the nations because of differing regulatory frameworks. Unauthorized GM (UGM) refers to those GM crops or products that have not received approval in a particular country. Monitoring the entry of UGM into the marketplace as well as in the suspected shipments is imperative from the regulatory aspect. DNA-based methods are preferred for testing of raw or partially processed food products, provided the quality of DNA to be ensured as its amplifiability may get hampered by the processing procedures or presence of inhibitors or due to complexity in composition in terms of ingredients. This review focused on possible approaches for adhering to the regulatory requirements while verifying UGM in food products. To this end, considering DNA extraction a crucial step, technical challenges and approaches for extracting purified DNA and necessary quality checks were briefly described for quality assurance. In view of the complexity and wide range of ingredients in these products, this article proffers both the amplification-as well as sequencing-based methods, which can be efficiently and reliably applied to check for presence of UGM ingredients. We also shed light on the comparative assessment of these methods so that their suitability in GM detection by a testing laboratory could be explored on the basis of regulatory requirement and availability of information of transgenic DNA.