## 3 The Critical Importance of Product Identity in Agricultural Supply Chains
### Industry Implementations in Agricultural Supply Chains  
Blockchain applications in agriculture have moved from concept to practice in recent years, with numerous case studies and pilot projects demonstrating its value. Below, some notable implementations by industry and government are highlighted. Global retailers and food companies: One of the most cited examples is Walmart's use of blockchain for food traceability. In partnership with IBM's Food Trust platform (built on Hyperledger Fabric), Walmart conducted trials tracking mangoes and pork. The results were dramatic--tracing the source of sliced mangoes went from taking nearly seven days with traditional systems to just 2.2 s using the blockchain solution [7]. Every step of the mango supply chain (farm, import, distribution centre, store) was recorded on the ledger, allowing instant lookup of origin and handling data. Following these pilots, Walmart mandated its leafy green suppliers to join the blockchain system to enable rapid recalls and improve food safety. Similarly, Carrefour, a large European retailer, has implemented blockchain tracking for a range of products (chicken, eggs, milk, cheese, fruits, among others) in collaboration with IBM [4]. Consumers can scan QR codes on Carrefour products to see detailed provenance information--for example, the exact farm where a chicken was raised, what it was fed, slaughter date, and transport details [4]. This level of transparency has reportedly boosted consumer trust and even increased sales for those products. Carrefour noted a \"halo effect\" where shoppers' confidence in one blockchain-tracked product (say, free-range chicken) positively influenced their trust in other Carrefour products [4]. The company saw pomelo grapefruit sales climb after  
Figure 5: Process flow for implementation of DIDs and digital twins in agricultural supply chains. introducing blockchain traceability, as customers felt assured of the fruit's origin and quality. These real-world outcomes underscore that blockchain can enhance brand reputation and consumer confidence when applied to food quality and safety verification. Producers and exporters: Agricultural producers and exporters have also adopted blockchain to differentiate their products and meet import requirements. For example, the coffee industry has seen blockchain pilots to certify origin and fair payment. Startups such as _Provenance_ worked on projects linking coffee farmers to consumers. Coffee beans are tagged and logged on blockchain from the farm, through cooperatives, to the roaster, using RFID/QR codes to create a digital identity for each lot [30]. This ensures that claims about sustainable farming practices or single-origin status are backed by an unbroken record. In one Provenance pilot, small-scale fishermen in Indonesia registered their tuna catches via text message to a blockchain, which generated a unique ID for each fish and logged subsequent processing steps [30]. This system allowed end consumers in Europe to scan a package of tuna and see its journey, verifying that it was caught legally and met sustainability standards (with fisher IDs and compliance info on record). Another notable implementation is by Bumble Bee Foods, which used blockchain to trace yellowfin tuna from Indonesian fisheries to North American dinner tables, enabling consumers to verify the seafood's authenticity and sourcing with a QR code scan. In the produce sector, growers and exporters of high-value foods (like organic bananas, specialty grains) are using blockchain-based platforms to meet stringent import regulations and prove that their products are exactly what their labels claim. Government and regulatory initiatives: Governments have recognised the potential of blockchain to improve food safety oversight and have launched supportive initiatives.