Mapping of RFID tag readability in relation to the food content in a refrigerated sea container at 915 MHz

Perishable foods are extremely sensitive to temperature abuse often observed during sea transportation, which regularly involves long transit times. The goal of this study was to compare the effects of the cargo on RFID (radio frequency identification) tag readability to achieve real-time temperature monitoring. A 12 m long refrigerated sea container (68 m(3)) and a 915 MHz RFID system were used. The container was loaded three times with different food products: canned vegetables, fresh meat and frozen bread. Each load was instrumented with 42 RFID tags evenly distributed throughout the volume. Results showed that canned vegetables provide the best readings (97.6% of tags read), followed by fresh meat (61.9%) and frozen bread (57.1%) respectively. These results validated that radio waves at 915 MHz are absorbed by high water as well as ice contents. However, spacing between metal surfaces and tags can allow excellent RFID readability even if RF reflects on metallic surfaces. Industrial relevance: The food industry is facing great challenges when it comes to food transportation and distribution. Marine transportation is a slow operation that can expose shipments to a significant range of non-ideal temperatures. Refrigeration units may experience failure during shipment, which inevitably causes losses in quality. The implementation of a real-time temperature monitoring system within a container can provide a good tool to address this issue. Radio frequency technology definitely offers additional benefits such as real-time monitoring as well as tracking and tracing. (C) 2010 Elsevier Ltd. All rights reserved.