Approaches to check unauthorized genetically modified events in supply chain: Challenges and solutions in the Indian context

The approval status of a genetically modified (GM) event varies from country to country. GM events approved in one country (considered as authorized GM or AGM) may not necessarily have the same approval status in other countries (considered as unauthorized GM or UGM). Detecting UGM in the supply chain is a challenge as the genetic information is not always available. In India, four Bt cotton events are approved, whereas several other GM events have been imported for research purposes. Many food derivatives (non-GM) are being imported from the countries where GM events of food crops are approved so it is necessary to track the unauthorized entry of GM products. Selected consignments or food products need to be checked for GM status for regulatory compliance. In farmers' fields, the chances of unintentional introgression or adventitious presence of transgenes also need to be monitored in a systematic manner. An appropriate strategy needs to be developed to check for UGM in the food and agricultural supply chain. In this article, approaches for UGM detection have been discussed with a focus on application in the Indian context. Detection methods based on the GMO matrix, multiplex PCR, real-time PCR (qPCR), and loop-mediated isothermal amplification (LAMP) could be employed keeping in view the regulatory requirement or practical application. For checking UGM with unknown genetic construct, methods such as next-generation sequencing (NGS) may be employed. The advantages and disadvantages of the different approaches are discussed in the function of the analytical strategy and its application for control purposes.