Recent developments in terahertz techniques for agricultural products and foods—an overview

Agricultural products and foods require rapid, accurate, and non-destructive methods for quality and safety assessment throughout production, processing, storage, and distribution. Terahertz (THz) spectroscopy and imaging have emerged as promising analytical tools because THz radiation is non-ionizing, sensitive to water, capable of penetrating many non-conductive materials, and responsive to low-frequency molecular vibrations. This review summarizes recent advancements in THz techniques for agri-food analysis, with emphasis on THz time-domain spectroscopy, continuous-wave THz systems, imaging modalities, and chemometric modelling strategies. Representative applications are discussed, including crop moisture monitoring, pest and disease diagnosis, soil and heavy-metal contamination assessment, pesticide residue detection, quality evaluation, authenticity identification, and seed characterization. The review also compares THz methods with other non-destructive techniques such as near-infrared spectroscopy and hyperspectral imaging. Although THz technology shows considerable potential for agricultural and food applications, its broader deployment remains limited by strong water absorption, shallow penetration depth, high system cost, environmental sensitivity, and insufficient standardization. Future research should focus on compact and affordable instrumentation, standardized measurement protocols, robust data models, multimodal sensing, and application-specific validation.