Targeted and Untargeted Methods for Fish Quality Assessment (Oncorhynchus mykiss)

Fish quality control demands efficient analytical solutions. While conventional (targeted) assessment methods are reliable, their labor-intensive and destructive nature drives the development of rapid, non-destructive (untargeted) technologies. This review features rainbow trout ( Oncorhynchus mykiss) as a key global aquaculture species. It compares, systematizes, and summarizes data on the capabilities, limitations, and prospects of applying targeted and untargeted assessment methods to fish raw materials in general and rainbow trout in particular. The review spans a decade of publications, comparing conventional quality assessment approaches (sensory, physicochemical, and microbiological methods) with advanced instrumental techniques (infrared spectroscopies, Raman spectroscopy, hyperspectral imaging, nuclear magnetic resonance spectroscopy). Untargeted methods, e.g., spectroscopy and imaging, enable rapid, non-invasive assessment of such key freshness parameters as chemical composition, lipid oxidation degree, spoilage, and storage time. In contrast, targeted methods remain crucial for validation and precise quantification of specific indicators, especially at later stages of spoilage. Untargeted methods show strong suitability for integration into real-time monitoring systems at fish processing facilities. However, their implementation requires robust calibration, specialized mathematical mode ls, and representative reference databases. Rainbow trout (Oncorhynchus mykiss) demonstrates the effectiveness of spectroscopic fish quality control methods, combining speed, non-invasiveness and the potential for online monitoring.