Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 19/09/2023 16:00:0019/09/2023 16:15:00Europe/ViennaAquaculture Europe 2023MICROPLASTICS CONTAMINATION IN DIFFERENT SEAFOOD SPECIES: COMPARISON BETWEEN FRESH AND CANNED SAMPLESSchubert 4The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982


D. M. Silva1,2 *, C. M. R. Almeida2,3, F.A. Guardiola4, S. Ramos2


1 ICBAS – School of Medicine and Biomedical Sciences Abel Salazar, University of Porto

2 CIIMAR – Interdisciplinary Centre of Marine and Environmental Research, University of Porto

3 Chemistry and Biochemistry Department, Faculty of Science of University of Porto

4 Immunobiology for Aquaculture group, Department of Cell Biology and Histology. Faculty of Biology, Campus Regional de Excelencia Internacional “Campus Mare Nostrum”, University of Murcia



* ICBAS – School of Medicine and Biomedical Sciences Abel Salazar – University of Porto, Rua de Jorge Viterbo Ferreira nº 228, 4050-313, Porto, Portugal; e-mail:



Between 1950 and 2021, the annual production of plastics has continually increased from 1.5 to 390 million metric tonnes. Regarding microplastics (MPs), plastic particles smaller than 5 mm, there is a worldwide growing interest and awareness on its impacts in the marine environments and organisms. Seafood has a crucial role for human consumers because it is an important source of high-quality proteins, unsaturated fatty-acids, fat-soluble vitamins and minerals, with numerous nutritional and health benefits. Thus, understanding the potential contamination of seafood with MPs is critical for food security and human health. Seafood is also highly perishable, and several preservation methods (like salting, freezing, or canning) are traditionally used to ensure the quality of the products. Canned seafood corresponds to approximately 10% of the total 178 million tons of the world fishery production, with the existence of a wide variety of canned organisms (e.g., fish, molluscs, crustaceans), immersed in different edible liquids (e.g., sunflower oil, olive oil, tomato sauce). Since consumers eat these products without any additional cleaning process, from a health perspective it is crucial to have a better understanding on possible MPs contamination both in the food tissues, as well as in the respective immersive liquids. The occurrence of MPs has been widely studied for several seafood species but, regarding canned seafood, there is still limited information. The main objective is to better understand possible MPs contamination during the canning processing of the seafood. From our knowledge, this is the first study comparing the occurrence of MPs in fresh and canned samples from the same seafood species.

Materials and methods

Four seafood species with relevance for human diet were selected and studied, both in fresh and canned samples: sardine (Sardina pilchardus), chub mackerel (Scomber colias), octopus (Octopus vulgaris) and mussels (Mytilus galloprovencialis). Fresh seafood was obtained directly from fisheries harbor, and canned seafood were obtained from local markets. MPs were extracted using 30% H2O2 to digest organic content, followed by vacuum-filtration and subsequent observation under a stereomicroscope, according to a previously optimized protocol. For canned samples, the edible tissues and immersion liquids were separately analyzed; for the fresh samples, MPs contamination was investigated in subsamples from the dorsal muscle of the organisms.


For all the fresh samples (n= 107), an average (± SD) of 0.086 ± 0.088 MPs/g of was obtained, while for the canned samples (n= 50), an average (± SD) of 0.040 ± 0.070 MPs/g of seafood tissue was observed. In general, some variability among MPs concentrations were observed in the two types of samples: sardine presented an average of 0.211 ± 0.074 MPs/g for fresh samples, and 0.020 ± .0.052 MPs/g for canned samples (in tomato sauce and sunflower oil); for octopus, an average of 0.006 ± 0.009 MPs/g in fresh samples, and 0.070 ± 0.106 MPs/g in canned samples (in tomato sauce) were obtained; concerning mussels, fresh samples presented an average of 0.066 ± 0.095 MPs/g, while canned samples (in escabeche sauce) presented 0.050 ± 0.071 MPs/g; for chub mackerel, an average of 0.060 ± 0.115 MPs/g for fresh samples, and 0.040 ± 0.052 MPs/g for canned samples (in sunflower oil) were reported. Also, an average of 0.004 ± 0.012 MPs/mL was obtained for the immersion liquids from the cans, an important finding since some of the liquids are ingested by human consumers. Microplastics were observed in all the studied seafood species including fragments, films and fibers from eleven different colors, and with a size range from 250 to 3000 µm. Plastic polymers such as polypropylene, polyester, polyethylene, rayon, polyvinyl and nylon were identified through FTIR analysis.


The present study shows MPs contamination in four relevant and commercialized seafood species, in both fresh and canned samples. This is an important finding, indicating that MPs contamination in seafood may result from two paths: i) direct and continuous contact between marine organisms and the surrounding contaminated environment, or ii) human handling and industrial process as canning. Quantifying and regulating MPs in canned seafood is crucial to increase food safety and human health, and a better knowledge on the possible MPs contamination from the capture of seafood organisms until the final products sold to consumers (considering all the human handling and industrial canning steps) is of major importance for a better understanding of MPs occurrence in canned seafood.


This research was partially funded by Ocean3R (NORTE-01-0145-FEDER-000064) and ATLANTIDA (ref. NORTE-01-0145-FEDER-000040) projects, supported by the Norte Portugal Regional Operational Programme (NORTE 2020) under the PORTUGAL 2020 Partnership Agreement and through the European Regional Development Fund (ERDF). Also, FCT is awarded by the Strategic Funding UIDB/04423/2020 and UIDP/04423/2020 through national funds provided by FCT and ERDF, and a PhD fellowship to DMS (2020.06088.BD) and a research contract to S. Ramos (DL57/2016/CP1344/CT0020).