Development of monitoring applications for refrigerated perishable goods transportation

Perishable food products are at risk of suffering various damages along the cold chain. The parties involved should control and monitor the conditions of goods in order to ensure their quality for consumers and to comply with all legal requirements. Among environmental parameters during transport, temperature is the most important in prolonging the shelf life of the products. The aim of this PhD thesis is to improve the control during transport, storage and distribution through the development of monitoring applications. The integration of emerging information technologies can now provide real-time status updates. As a first approach, a deep review of the state of the art has been done. That includes scientific literature, websites, books, articles, etc. in different areas. After the revision various key technologies were identified: RFID, WSN, chemical sensing and fieldbus networks. The experimental work about RFID has been focused to the adaptation of miniaturized semi-passive temperature loggers for monitoring refrigerated shipments by truck. This study included an analysis of the amount of local deviations, the detection of temperature gradients, and the estimation of the minimum number of sensors that are necessary for reliable monitoring inside a truck or container. These devices are useful tools for improving the transport chain and detecting weaknesses by identifying specific problem areas where corrective actions are needed. In a first step, the RFID tags were tested by studying the temperature distribution in a pallet. Then, 15 shipments from a wholesale company in Germany in compartmented trucks were monitored, covering different temperature range conditions. Also, the potential of wireless sensor technology for monitoring fruit storage and transport conditions has been explored, focusing on ZigBee technology with special regard to two different commercial modules. The main contributions in this area relate to the analysis of battery life under refrigerated conditions and the evaluation of the ...