EMERGED AND EMERGING THREATS IN MARINE FOOD SYSTEMS AND FOOD SAFETY

Marine food systems are increasingly shaped by anthropogenic pressures—warming, biodiversity loss, pollution, and intensified exploitation—that alter hazard landscapes and challenge conventional food-safety paradigms. The One Health framework, which links human, animal, and environmental health, offers an integrated lens for surveillance and risk management spanning ecosystems, primary production, processing, and retail exposure. This thesis operationalizes that perspective across four complementary lines of evidence: (i) retail-level antimicrobial resistance (AMR) in psychrotrophic Pseudomonas from fresh finfish fillets; (ii) a critical review of microplastics (MPs) in edible aquatic products and their implications for human exposure; (iii) the first metataxonomic baseline of the swordfish (Xiphias gladius) gut microbiota; and (iv) governance and hygiene guidance for a neglected/under-utilized species (NUS), the Patagonian red octopus (Enteroctopus megalocyathus), in artisanal value chains. Together, these studies generate empirical measurements, methodological synthesis, and context-appropriate controls intended to protect consumers while supporting sustainable seafood systems. Across chapters, the thesis advances a prevention-first agenda. At retail, managing initial Pseudomonas loads and realistic shelf-life windows is essential for sensory and safety endpoints; species effects (lower loads in salmon vs plaice; cod intermediate) argue for product-specific expectations and controls. For MPs, science-policy progress hinges on method harmonization and exposure standardization to move from presence toward dose–response. For swordfish, the microbiome baseline provides a scaffold to interrogate spoilage trajectories, ARG carriage, and handling effects across the chain; extending to functional ‘omics will increase decision relevance. For NUS, embedding simple, verifiable hygiene practices in co-management, coupled with training and modest infrastructure (potable ice, clean tanks, hand hygiene), can de-risk market expansion while supporting equitable livelihoods. Limitations map a clear research program: broaden spatio-temporal AMR surveillance beyond Pseudomonas and link phenotypes to resistomes; standardize MP analytics and exposure metrics that capture co-exposures; resolve gut compartments and functions in swordfish to connect taxa with spoilage and resistance traits; and validate Good Hygiene Practices adaptations for small-scale octopus chains under real constraints. Nonetheless, the thesis contributes a One Health-rooted coherent set of measurements, baselines, and practices that tie laboratory, vessel, landing site, plant, and retail into a single surveillance-and-control continuum. The overarching conclusion is pragmatic: invest in integrated AMR/MP monitoring with harmonized metadata, validated anti-biofilm sanitation and time–temperature discipline, species-specific microbiome baselines, and context-appropriate hygiene for NUS. Such integration strengthens consumer protection while aligning seafood safety with ecosystem stewardship and community resilience in an era of environmental change.