Food preservatives are widely employed to safeguard product quality, extend shelf life, and prevent deterioration caused by microbial growth, oxidative reactions, and enzymatic activity. Their presence at trace levels within complex food matrices, however, poses analytical challenges that demand sensitive, selective, and reproducible detection methods. This chapter provides a comprehensive overview of conventional, advanced, and emerging strategies for preservative analysis, highlighting their relevance in modern food systems and regulatory contexts. Preservatives are categorized into antimicrobials (sorbates, benzoates, nitrates, parabens), antioxidants (BHA, BHT, tocopherols, ascorbic acid), and enzyme inhibitors (sulfites, citric acid), reflecting their functional diversity. Conventional techniques such as HPLC, GC, TLC, UV–Vis spectroscopy, and titrimetry remain widely used, though they are often limited by solvent consumption, labor intensity, and portability. Advanced chromatographic and spectroscopic approaches (UHPLC, LC–MS/MS, GC–MS, NMR, FTIR) enable structural elucidation and multi-residue detection, albeit with higher costs and technical expertise requirements. In parallel, emerging technologies, including biosensors, lab-on-chip systems, hyperspectral imaging, and ambient mass spectrometry, offer rapid, portable, and non-destructive analysis. Data-driven approaches, particularly chemometrics, machine learning, and AI, enhance spectral interpretation and predictive modeling, while integration with IoT and Big Data paves the way toward Industry 4.0-ready food monitoring platforms. The chapter also compares international regulatory frameworks (EFSA, FDA, Codex, and national systems), underlining key differences in permitted limits and labeling requirements. Future perspectives emphasize ultra-trace detection, green analytical chemistry, and digital integration to ensure food safety, sustainability, and consumer trust.