The increasing occurrence of parasites, namely Microsporidia and Anisakids, in economically relevant fish species such as Pouting (Trisopterus luscus) and European hake (Merluccius merluccius) raises concerns regarding the quality and safety of seafood products, presenting a significant public health risk. Therefore, this study aims to understand how Microsporidia and Anisakids, both bearing significant parasitic loads in these fish species, impact the quality and nutritional muscle traits across different seasons.
Samples were collected from European Hake from Southeast Ireland and Gulf of Biscay, and from Pouting captured in Portuguese waters. Pouting and European hake muscle samples from 30 individuals per season were analyzed for proximal composition (ongoing), color, texture, pH, and parasites. Microsporidia, the most prevalent parasite group in Pouting muscle, was categorized into four intensity levels: absence (0), low (1-20), medium (20-50), and high (>50). Anisakids, the most prevalent parasite group in European hake muscle, was categorized into three density levels: low (1-5), medium (5-10), and high (>10).
When looking at how organoleptic properties varied with seasonality, significative differences (p < 0.05) were observed in Pouting. Spring and Summer had higher muscle lightness (L*), redness (a*) and yellowness (b*) when compared with Autumn and Winter. In terms of textural properties, Spring showed the lowest Cohesiveness and Chewiness values.
The parasitization level also significantly (p < 0.05) impacted pouting muscle color. A decrease in muscle lightness (L*) was observed, particularly with higher microsporidia parasitic levels (>50), which could compromise consumers quality requirements. Overall, muscle samples collected during Spring and Summer exhibited higher quality compared to those collected during Autumn and Winter. Ongoing research includes parasite infection level determination, nutritional assessments, and analyses focusing on European hake.
Acknowledgments:
This work was funded by Innovation Pact, Project No. C644915664-00000026, known as the “Blue Bioeconomy Pact” and by FCT in the framework of the Programme Portugal2020 to CIIMAR (UIDB/Multi/04423/2021 and UIDB/Multi/04423/2022), and the PhD fellow to Carla Sousa (2023.00570.BDANA) and Fernando Atroch (2022_105_BI_BioeconomiaAzul).