Flexible SERS Substrates for On-Site Food Safety Monitoring: A Five-Year Progress Review

Surface-enhanced Raman scattering (SERS) technology has attracted growing interest for on-site food safety monitoring, with flexible substrates offering distinct advantages in conformal sampling, portability, and non-destructive analysis. This review systematically summarizes recent advances in flexible SERS substrates for practical food safety applications, covering design strategies including material selection, structural engineering, and performance enhancement, as well as diverse applications such as swabbing-based detection, in situ analysis, enrichment-assisted trace detection, and multiplexed contaminant identification. Challenges and future perspectives are also discussed, focusing on portable instrument adaptation, simplified sample pretreatment, intelligent data analysis, and scalable manufacturing. This review aims to bridge the gap between laboratory research and field deployment, providing valuable insights for the commercialization of flexible SERS technology in real-world food safety monitoring.