Effects of seasonal dynamics and Anisakis spp. infection levels on the fillet quality of European Hake (Merluccius merluccius)

The rising prevalence of parasites in seafood threatens safety, quality and economic stability. Anisakis spp., identified by EFSA as a major public health concern, infects many commercialised fish species, including European hake (Merluccius merluccius). This study assessed (1) the impact of Anisakis spp. infection on the dorsal muscle quality and (2) seasonal dynamics in fillet quality. Dorsal muscle collected from two regions over a year (n = 30 per season/region), were analysed for proximate composition, pH, texture, colour, lipid oxidation, and antioxidant capacity. Winter samples showed significantly lower lightness (L*) (SI: 45.64 ± 0.47, p < 0.001; BB: 49.63 ± 0.52, p < 0.001), redness (a*) (SI: -0.83 ± 0.16, p < 0.001; BB: -0.69 ± 0.12, p < 0.001), and yellowness (b*) (SI: -4.36 ± 0.10, p < 0.001; BB: -3.82 ± 0.18, p < 0.001), along with exhibited increased cohesiveness (SI: 0.45 ± 0.01, p = 0.010; BB: 0.51 ± 0.01, p < 0.001) and decreased hardness (SI: 0.31 ± 0.01, p < 0.001; BB: 0.34 ± 0.01, p < 0.001) and chewiness (SI 0.13 ± 0.01, p < 0.001; BB: 0.17 ± 0.01, p < 0.001). Nutritional analysis revealed higher protein (SI: 18.73 ± 0.16, p < 0.001; BB: 18.15 ± 0.16, p < 0.001) and lower lipid content (SI: 0.60 ± 0.04, p < 0.001; BB: 0.68 ± 0.03, p = 0.032) in winter. While Anisakis spp. infection levels did not affect pH, nutritional value or texture, it impacted muscle colour in Southeast Ireland, with yellowness (b*) values significantly higher at high parasitisation levels (0.11 ± 0.69; p = 0.012). These findings highlight the need for seasonal-specific quality control in the seafood industry.