Exposure, fate and impact of food preservatives in the environment
Abstract Food preservatives and preservative-related additives support food safety and shelf-life extension, but their environmental relevance depends on compound-specific release pathways, transformation behaviour, and receiving compartments. This structured narrative review synthesises evidence on the environmental exposure, fate, transformation products, and potential impacts of major preservative classes, including weak-acid antimicrobials, nitrite/nitrate curing systems, sulphites, synthetic phenolic antioxidants, chelators, bacteriocins/polyenes, and selected plant-derived antimicrobial or antioxidant compounds. The evidence shows that environmental loading can occur through food-processing effluents, household disposal, wastewater treatment, discarded food, landfill leachate, compost/digestate, sludge, biosolids, and preservative-loaded packaging or coating residues. Wastewater treatment should not be interpreted as uniformly ineffective; rather, removal, transformation, and partitioning are class-specific. Weak acids, sulphites, peptide preservatives, and many plant-derived compounds are often readily degraded or rapidly transformed, although near-field exposures and transformation products may still be relevant under high-loading or matrix-protected conditions. In contrast, synthetic phenolic antioxidants, EDTA and selected metal–EDTA complexes, paraben-related transformation products, and sludge-associated residues require closer environmental attention because of persistence, solid partitioning, metal-complex mobility, biosolid transfer, or transformation-product formation. The review also emphasises that ‘natural,’ ‘organic,’ and ‘clean-label’ descriptors should not be used as proxies for environmental safety. Environmental assessment should instead be based on measured occurrence, realistic exposure scenarios, degradation pathways, transformation products, sludge/biosolid partitioning, soil and sediment fate, plant uptake, and ecotoxicological endpoints. Future work should prioritise transformation-product-aware monitoring and class-specific risk assessment.