In this paper we propose a novel technique to implement secure and efficient applications for the agri-food certification chain. Our proposal relies on RFID technologies which is probably the most relevant enabling solution for ubiquitous IoT systems. We analyze a recently introduced and promising RFID tag and we prove it is possible to certify its genuineness without installing any third party application upon the consumer smartphone. The proposed solution is based on a lightweight security technique which provides the mirroring of the tag identifier combined with the encryption of a NDEF formatted file.