# IoT Services for Monitoring Food Supply Chains
## 2 Literature Review
### Advanced IoT Architectures and Smart Sensor Technologies  
The utilisation of new IoT-based real-time monitoring technologies is a promising new field in agrifood supply chains, with applications in precision, traceability, visibility, and controllability. IoT is rapidly expanding and has the potential to become a massive source of data for agrifood supply chains. Although these new technologies are expected to lead to more efficient and sustainable food chains in the near future, limited attention has been given to their potential applications in the food sector. As a result, this study contributes to addressing the research gap in the lack of awareness about the applicability of real-time monitoring technologies based on IoT devices in the food sector, as well as the prevalent behaviours related to these technologies [15]. However, significant literature reviews have successfully implemented IoT-based food quality monitoring using low-cost sensors. An innovative IoT-based food quality monitoring approach using low-cost sensors was initially implemented, where the system consisted of gas, temperature, and humidity sensors that provided the necessary information for assessing the quality of the packaged product [16]. A real-time tracking system for estimating the shelf life of fruits and vegetables was subsequently implemented [17]. A Blockchain-based Cold Chain Logistics Traceability System for fresh agricultural products was also developed. Finally, a systematic review of real-time food tracking technologies highlighted key elements of agrifood supply chains and IoT technologies [18]. The continuous monitoring of specific quality characteristics of products during transport and storage throughout production and logistics processes is considered a cornerstone for ensuring product quality. In addition, often, even a slight deviation from the predetermined values, e.g., regarding the colour or smell of the product, results in the rejection of the product. Thus, integrating innovative sensors, combined with advances in food safety, has yielded promising results leading to the development of Intelligent Packaging (IP). During the monitoring of products at the package level, the sensors commonly used are passive and visual indicators of freshness due to their relatively low price. They are also valuable for the consumer, as they eliminate the possibility of unmonitored food deterioration in the event of mishandling during the transfer from the packaging to the fork. At the same time, sensors at the package level can be used to continuously validate the product's expiration date, as the expiration date assumes retaining specific environmental conditions at all stages. Therefore, tracking at the product package level downstream in the cold supply chain is particularly important and can now be fully customised according to the product and the specific features of the supply chain. Various innovative sensor device technologies are now available to collect information on packaged food products, e.g., external and internal sensors. First, external sensors are attached to the outside of the package. Examples of these devices are temperature and physical vibration sensors. The second type is placed inside the package, in the upper space, or attached to the lid, for example, biosensors and indicators of biological growth. The sensors could share the measurements by communicating with data collection and utilisation centres, using a 5-layer architecture, and operating in a cloud computing environment [19]. Certain Internet of Things (IoT) applications, particularly those focused on monitoring the quality of agrifood products, have a distinct set of requirements that must be considered for effective implementation. These applications often require long-range communication capabilities to ensure data can be transmitted over significant distances without losing integrity or reliability. Additionally, they typically operate with low bit rates, meaning that the amount of data transmitted at any given time is minimal.