This article gives a review of surface-enhanced Raman scattering (SERS) sensors for food safety and environmental pollution monitoring. It introduces the basic concepts of SERS substrates, SERS enhancement factors and mechanisms, SERS probes/labels, molecular recognition elements as well as optofluidic SERS devices (SERS sensors integrated with microfluidics). This article places an emphasis on the design strategies of various SERS sensors by utilizing fingerprinting SERS spectra or by using SERS probes. It highlights the applications of SERS sensors in detection of heavy metals (such as Hg2+, Pb2+, Cd2+ and As3+), inorganic anions (nitrite, nitrate, perchlorate and fluoride), toxic small molecules (polycyclic aromatic hydrocarbon, polychlorinated biphenyls, herbicides, pesticides, antibiotics and food additives), as well as pathogens (bacteria and viruses). (C) The Author(s) 2018. Published by ECS.