Recent advances in integrated dual-mode optical sensors for food safety detection

Food safety poses a threat to public health and raises serious concerns worldwide. Contaminants include various substances such as pathogens, toxins, pesticides and heavy metals. Therefore, food safety detection is an urgent need. Recently, dual-mode sensors have ensured the accuracy of assay results by integrating two signals into one, demonstrating their potential application in primary food safety screening tests and quantitative assays. In particular, visible optical signals from dual-mode sensors can satisfy the need for onsite contaminant monitoring. Although dual-mode sensors have been an area of growing interest, the design strategies for sensors tailored to food contaminants are rarely highlighted and discussed. Herein, we review the five-year progress in dual-mode optical detection methods for food contaminants. In particular, this article focuses on exploring the various sensing performances of dual-mode sensors, including the types, sensing principles, advanced design strategies, and applications. Finally, the current challenges and future developments in dual-mode sensors are briefly discussed. Integrated dual-mode optical sensors have received considerable attention regarding food safety. Compared with a single signal, the multichannel biosensor can essentially eliminate the influence of the complex food matrix and reduce false positives and negatives; signals can be statistically tested to verify the reliability of the results.