# A Full Technological Traceability System for Extra Virgin Olive Oil
## Materials and Methods
### App (Infoliva) for EVOO Traceability  
The app (Infoliva) for the EVOO traceability data collection was developed to support the in-field operation from standing trees to olive oil mill, providing the operators with a simple and easy-to-use tool for smartphones. The information registered through the app is stored on an internal database and subsequently synchronized on a remote server. In addition, the app uses the smartphone components and sensors (i.e., GPS and Bluetooth) to collect precious data. The GPS receiver was used to collect the trees' geographical positions. The Bluetooth device was used for the connection between the smartphone and the external customized portable RFID reader. Internet connectivity was needed for the synchronization on the remote server; this operation can be achieved both in-field (if the internet connection is available) or afterwards, when field operations are concluded and the internet signal becomes available. The app (Figure 3A) was predisposed to rapidly operate choices such as the cultivar identification phase or the olive harvest phase and remote synchronization phase. Each activity regarding the Infoliva app is described below and represented in Figure 3:  
* Main activity: the start page allows one to select the phase to be executed (standing olive tree or olive harvest). * Standing olive tree (Figure 3B): through the \"scan\" button, the Bluetooth connection of the smartphone to the customized portable RFID reader is achieved. The device is in a waiting state ready to receive the tag RFID1 unique code that identifies the tree. When the RFID code is received, the app checks for the presence of the code. If it is an existing code, all data will be loaded and can be modified up to 2 h, while if it is a new code, the fields will be activated to enter the following information: cultivar (Carboncella, Frantoio, Leccino), GPS (automated inserted and unmodifiable), date (data; automated inserted and unmodifiable) and notes. Once inserted, the data will be saved on an internal database. Data updating and deletion functions have also been implemented and are available up to 2 h.
* Olive harvest phase (Figure 3C): as reported above, the scan button allows the reading of a RFID tag via Bluetooth. The procedure consists of the following: (1) reading the RFID1 positioned on the tree that needs to be harvested, (2) association of the plant tag to the related crates where the olives  
Figure 2: **(A)** The RFID1 standard used is UHF at 860 MHz, Class 1 Gen 2, waterproof coin shaped with central hole; (**B**) the RFID2 is UHF at 860 MHz, waterproof flexible band with two holes at the extremities fixed with a small cord on the crate. are collected, (3) adding the following information for each crate: crate weight, olive maturation (high, medium, low), olive defects (high, medium, low), date (data; automated inserted and unmodifiable), notes. Control procedures to verify the data consistence and coherence were implemented. As above described, data update and delete functions were also implemented and are available up to 2 h.  
The whole EVOO supply/processing chain information, from standing trees to consumer, described in Section 2.1, was implemented in a personal cloud database. The standing tree and in-field information were inserted with the dedicated devices mentioned above; the other information (yield after pressing, nutritional information) were manually inserted by the operators along the chain through a web interface. The database and the architecture were built in order to be easily implemented with blockchains. A schematic description of the blockchain data flow is summarized in Figure 4. This figure, independently from the kind of platform used, could represents a typical blockchain integration. For example, the remote synchronism (Figure 3D) manages the synchronization with the remote server and the blockchain.