Instrumental detection of fish freshness in research and food industry: a review

Fish is the vital source of easily digestible protein and a primary source of animal protein for millions of people worldwide. Freshness strongly influences market value, consumer acceptance, and safety, making accurate quality assessment essential for both domestic and export markets. Conventional sensory and chemical methods, including organoleptic evaluation, TVB-N, and microbial counts, are often subjective, destructive, and time-consuming, limiting their real-time application. The recent technological interventions in this area include rapid and non-destructive techniques, such as electronic nose, electronic tongue, near-infrared (NIR) and UV-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, magnetic resonance imaging (MRI), and biosensors. These technologies, when integrated with computer vision, robotics, and artificial intelligence, enable automated and highly accurate freshness monitoring across the fish supply chain. Present review discusses the key points related to fish freshness detection, principles, strengths, limitations and comparative studies of various instrumental techniques along with highlighting the potential directions for future research in this evolving field. Future research should focus on developing portable, cost-effective, and smart systems that combine advanced sensing technologies with real-time data analytics. Such innovations will improve fish quality control, reduce post-harvest losses, enhance food safety, and support sustainable fisheries management.