The cold chain system is usually adopted to follow the perishable food products during storage, transport and sale for keeping the freshness. Based on Internet of Things (IoT) technology, the sensor tags which are semi-passive tags integrated with sensors can monitor temperature in smart cold chain system. In this paper, a Refined Smart Cold Chain System (RSCCS) was proposed in which the semi-passive tags are replaced with the passive tags to reduce the cost. For availability and scalability, a new type of RFID application named 2G-RFID-Sys is applied to our design. Our proposal keeps the advantage of the original 2G-RFID-Sys and further ensures the correctness of the system execution. Not only the food producer can ensure the food freshness but also the consumer can safely purchase the products via RSCCS without accessing the backend system. (C) 2014 Elsevier Ltd. All rights reserved.