Abstract: Under the background of epidemic prevention and control, the quality and safety of cold chain foods has attracted much attention. However, the construction of the food cold chain traceability system is currently imperfect, and there are still some problems in this field, such as lack of trust, information asymmetry and lack of traceability links. In view of these problems, this paper proposes a new idea for the construction of the food cold chain traceability system based on quantum blockchain. In quantum blockchains, the records in a block are encoded into a series of entangled quanta. By using quantum key distribution to replace the traditional asymmetric cryptographic transmission of blockchain and as well as identity authentication through quantum signature, the entangled quantum state control effect can be formed and a quantum consensus can be reached, ensuring real tamper-proof data transmission between any nodes and preventing data from being tampered with. Combined use of various technologies such as distributed storage and smart contract allows all nodes of the traceability system to participate in maintaining data safety. In this paper, the cold chain traceability system is constructed from three layers: cold chain information collection business, network data management and system application, and the operating mechanism of the system is discussed. This paper highlights that the current dilemma of cold chain food traceability can be solved by giving full play to the advantages of blockchain through quantum communication technology, which will provide a reference for exploring the construction of a real, efficient and sustainable food safety traceability system.

Key words: quantum blockchain; food cold chain traceability system; quantum key distribution