Comprehensive screening of the contaminants in feeds and gilthead sea Bream (Sparus aurata) fillets by GC and LC coupled to HRMS technique

• Combined use of GC and UHPLC with IMS-QTOF for analysis. • Nearly 2000 organic compounds investigated in marine food production chain matrices. • Plant feed showed highest pesticide and PAHs indices, with feed-to-fillet transfer. • Alternative material showed the least exposure to contaminants. • Contaminant profile decreased over the past decade. Aquaculture plays a crucial role in addressing the increasing global demand for fish, requiring the development of sustainable feed formulations. However, incorporating alternative ingredients in feeds may introduce pollutants not commonly linked to fish farming. This study examines the occurrence of potential pollutants across the marine food production chain—from raw ingredients to commercial feeds, and final fish fillets—using a feeding trial with gilthead sea bream. Eighteen raw ingredients, three different diets (each with two pellet sizes), and 48 fillet samples were analysed using advanced analytical platforms: liquid chromatography (LC) and gas chromatography (GC), both coupled to high-resolution mass spectrometry (HRMS), including ion mobility-quadrupole time of flight (IMS-QTOF) and GC-Orbitrap MS. The results revealed the presence of typical plant-associated ingredients, such as pesticides and PAHs, in ingredients and feeds. Residues of veterinary pharmaceuticals were also detected in animal by-products ingredients, along with emerging contaminants like UV filters, musks, and phthalates. Interestingly, these contaminants did not show correlation with diet composition, suggesting contamination may originate from processing or storage. Notably, diets containing alternative ingredients showed lower contaminant loads compared to previous studies, with minimal transfer of pollutants to fish fillets. These findings highlight that alternative feed strategies can contribute to safer sustainable aquaculture practices without compromising consumer health.