Transformation-Aware Analytical Strategies for Food Preservatives and Their Byproducts: Challenges and Emerging Detection Approaches in Complex Food Matrices

Food preservatives are essential for extending shelf life and maintaining food safety, but conventional analysis largely focuses on quantifying parent compounds and may overlook transformation during processing and storage. Changes in pH, light, temperature, available oxygen, and interactions with food matrix components can alter preservative stability and generate transformation products (TPs) with distinct analytical and toxicological characteristics. This review critically evaluates analytical strategies for food preservatives by integrating preservative chemistry, transformation pathways, matrix effects, toxicological considerations, and analytical performance within a unified perspective. Conventional spectroscopic methods and chromatographic techniques, together with hyphenated mass spectrometric approaches, particularly high-resolution mass spectrometry (HRMS), are critically assessed for routine, multi-residue preservative determination in food matrices and transformation product characterization. A mechanism-driven classification based on physicochemical properties, chemical reactivity, and transformation potential is proposed to guide rational method selection. Building on this perspective, a Transformation-Aware Analytical Framework (TAAF) is proposed to integrate matrix characterization, transformation-risk assessment, targeted analysis, suspect and non-target screening, and computational tools for improved preservative monitoring. The review emphasizes a shift from parent compound analysis toward transformation-aware and mechanism-driven analytical strategies that better reflect preservative chemical behavior, toxicological risk, and consumer exposure in complex food matrices.