Report on the Monitoring Programme for the Presence of visible Parasites in Fish (2025)

Parasites including nematodes (roundworms), cestodes (tapeworms) and trematodes (flukes), are natural and integral components of marine ecosystems. Some parasites of fish are typically more abundant and diverse than their hosts. Hence, in important commercially harvested fish species such as Atlantic cod, saithe and herring, potentially zoonotic nematodes within the anisakid family commonly occur. The EFSA Panel on Biological Hazards has concluded that no wild marine fish species from any fishing ground can be considered free of parasites of public health importance (EFSA BIOHAZ Panel et al., 2024a). Because visible parasites negatively affect food safety and consumer perception, food business operators (FBOs) are required to ensure appropriate evisceration, cleaning and visual inspection, including, where relevant, the manual removal of visible parasites from fillets by candling and/or trimming prior to marketing.
Under Regulation (EC) No 853/2004, FBOs must ensure that fishery products have been subjected to a visual examination for the purpose of detecting visible parasites and must not place fishery products that are obviously contaminated with parasites on the market for human consumption. Detailed rules for visual inspection to detect parasites in fishery products are given in Regulation (EC) No 2074/2005. In addition, Regulation (EU) No 2019/627 lays down practical arrangements for the performance of official controls on products of animal origin intended for human consumption including fishery products, to be performed by the competent authority or delegated bodies.
The present monitoring and control program on parasites, run by the Institute of Marine Research of Bergen on behalf of the Norwegian Food Safety Authority, aimed to verify that the visual examination procedures by Norwegian seafood companies are in compliance with the above-mentioned regulations.

A total of 321 fishery products (mostly head-off and eviscerated fish) were randomly collected by various Norwegian Food Safety Authority inspectors from 19 wild-catch fish processing plants across Norway during 2025 and sent to IMR for inspection for visible parasites following the procedures laid down in Regulation (EC) No 2074/2005. Of these products, 101 were Atlantic cod (Gadus morhua), 59 were tusk (Brosme brosme), 59 were saithe (Pollachius virens), 30 were Greenland halibut (Reinhardtius hippoglossoides), 23 were ling (Molva molva), 10 were haddock (Melanogrammus aeglefinus) while 39 were whole non-eviscerated Atlantic mackerel (Scomber scombrus). The inspection procedure involved brief visual inspection of the skin and visceral cavity of each product under good down-light conditions in a wet lab that mimicked a fish processing line.

Of the 321 products examined, 108 (34 %) had visible parasites, of which 61 (19 % of the total) were considered as “obviously contaminated with parasites”. Products of tusk were the most problematic, followed by saithe, cod, ling and haddock products. No visible parasites were detected in Greenland halibut nor in the non-eviscerated Atlantic mackerel. The larvae of anisakid nematodes (mainly Anisakis sp., and less frequently Phocanema sp.), were the most common parasites found. These roundworms occurred either encapsulated in visceral tissue remains or were about to migrate into the fish muscle (Figure 1, 2, 3). Additionally, larvae (metacercariae) of the parasitic trematode Cryptocotyle lingua* were occasionally observed as black spots on the fish skin and in the eyes of cod and haddock (Figure 4). In two saithe products, a non-zoonotic raphidascaridid nematode (Hysterothylacium sp.) and a cestode (possibly Hepatoxylon sp.) were found in some visceral tissue remains in the visceral cavity (see Table 1).

*Cryptocotyle lingua is a fish parasitic trematode (fluke). Its larval stage, known as metacercaria, commonly infects the skin of various fish species that more or less frequently enter the littoral zone where periwinkles occur abundantly (periwinkles act as 1st intermediate host of C. lingua, fish functions as 2nd intermediate host, while the parasite matures in fish-eating birds). In heavy infections, the metacercariae are readily visible as tiny black spots on the fish skin, a condition known as “black spot disease”. Additionally, metacercariae can occasionally be found subcutaneously in the fish flesh, thus potentially contaminating the distal parts of the fillets. EFSA has listed C. lingua as a zoonotic parasite (EFSA BIOHAZ Panel et al., 2024b).

Approximately one third of examined fishery products contained visible parasites, and about one fifth (19%) were considered to be obviously contaminated. The main parasite groups identified were the zoonotic anisakid nematodes Anisakis sp. and Phocanema sp. in the visceral cavity and fillets, and the trematode Cryptocotyle lingua in the skin. Most anisakid larvae were encapsulated in visceral tissue remains or were in the process of penetrating into the muscle, particularly in tusk, cod and saithe. Most cases in which products were considered obviously contaminated with nematode or cestode parasites (Figures 2, 3), could have been prevented through improved cleaning and final control practices.

EFSA BIOHAZ Panel (EFSA Panel on Biological Hazards), Allende, A., Alvarez-Ordóñez, A., Bortolaia, V., Bover-Cid, S., De Cesare, A., … Bolton, D. (2024)a. Re- evaluation of certain aspects of the EFSA Scientific Opinion of April 2010 on risk assessment of parasites in fishery products, based on new scientific data. Part 2. EFSA Journal, 22(11), e9090. https://doi.org/10.2903/j.efsa.2024.9090

EFSA BIOHAZ Panel (EFSA Panel on Biological Hazards), Koutsoumanis, K., Allende, A., Alvarez-Ordóñez, A., Bover-Cid, S., Chemaly, M., … Bolton, D. (2024)b. Re-evaluation of certain aspects of the EFSA Scientific Opinion of April 2010 on risk assessment of parasites in fishery products, based on new scientific data. Part 1: ToRs1–3. EFSA Journal, 22(4), e8719. https://doi.org/10.2903/j.efsa.2024.8719