Traceability is a critical component in supply chains to ensure transparency, quality control, and trust among stakeholders. However, current traceability systems face significant challenges, including the risk of data manipulation by unauthorised actors, a lack of system integration across participants, inefficient centralized processes, often manual in nature, and delays in accessing real-time information. In this work, we propose a novel real-time traceability system based on Blockchain and IoT technologies to address previous limitations. The proposed system uses IoT devices to automatically monitor environmental data and save it directly on a blockchain, ensuring immutability and eliminating the need for manual data handling. The use of blockchain guarantees decentralisation and trust among participants, while the IoT infrastructure provides real-time visibility throughout the supply chain. To enable efficient real-time data retrieval, the system employs an event-driven architecture, where data collected by IoT devices triggers events through smart contracts, allowing effective indexing and optimised querying of traceability data.