In foods, there are many types and sources of harmful substances that can accumulate in the human body, thereby posing a threat to human health. Therefore, it is crucial to develop efficient, rapid and portable visual detection devices with low detection limits. In recent years, nanozymes, nanomaterials with natural enzyme-like activity, have played an important role in the construction of colorimetric sensors due to their tunable enzyme activity and high stability, enabling efficient and rapid visual detection of harmful substances in foods. Redox-type nanozymes are the most researched nanozymes. Therefore, this paper introduces the types of redox-type nanozymes and elucidates their catalytic mechanisms. It focuses on reviewing the application of redox-type nanozymes in constructing colorimetric sensors for detecting common representative harmful substances (heavy metals, pesticide residues, and mycotoxins) in foods. Finally, we summarize the advantages and disadvantages of colorimetric assays based on redox-type nanozymes in the field of food safety detection, and propose some solutions to the problems in order to provide a reference for future research.

In recent years, black phosphorus, a new two-dimensional nanomaterial, has been widely used in sensors and analytical instrumentation due to its tunable band gap, high electron mobility and large specific surface area. This article introduces the structure and properties of black phosphorus and its preparation methods, and reviews recent progress in the application of electrochemical sensors based on black phosphorus for the detection of nutrients and harmful substances in foods, harmful substances in food packaging materials. Finally, we summarize the problems in the application of black phosphorus-based electrochemical sensors and provides some suggestions to solve these problems.