Parasites in fishery products - Laboratorial and educational strategies to control

Abstract

The presence of parasites, including Anisakis spp. larvae in fishery products jeopardizes their safety and quality, which is a matter of concern and a challenge for official authorities, as well as for food businesses operators, and a potential health risk to consumers. In the last ten years, a total of 2367 samples from different seafood products, whole fish (n = 1022), fish steaks (n = 417), fish fillets (n = 46), roes (n = 11), canned fish fillets (n = 35), fish fingers (n = 705), and ready-made Japanese dishes (n = 131) were analysed at the Laboratory of Pathology of Aquatic Animals of IPMA. From the fishery products analysed, a total of 4643 visible Anisakis larvae were collected from eighteen different species of whole fish and there were two cases with numerous larvae, although live larvae were only found in fresh fish. Anisakis larvae (n = 523) were collected from fish steaks, (n = 20) from frozen fish fillets, (n = 7) from five different brands of fish fingers, (n = 2) from two cans of cod fillets and numerous viable larvae were collected from the serosae of European hake fresh roes. The great majority of the larvae were identified as L3 Anisakis larvae. Plerocercoids of Gymnorhynchus gigas and Hepatoxylon trichiuri and the myxosporean, Kudoa spp. were also observed and led to the withdrawal of the fish from the supply chain. No Anisakis larvae were collected from the farmed fish as well as from the ready-made Japanese dishes. However, Kudoa hexapunctata spores were observed in the tuna muscle from one sashimi meal. The data shows that fresh fish with live Anisakis larvae have been marketed. Educational strategies concerning parasites were implemented with workshops, “Parasites in Fishery Products” to train and instruct professionals within the fish supply chain and training activities for target groups, including children, were promoted, to raise awareness of this issue. One of the most relevant outcomes obtained was the improvement of implementation of parasite identification techniques in the industry, including private labs, and consequently: (1) decrease in the parasitological analysis number of common parasites and (2) reduction in the analysis of anatomical structures confused with parasites requested to IPMA's Laboratory of Pathology. In addition, the practice of freezing trash fish used to feed farmed fish, and the placement of nets at the water entry points of the earth ponds, in order to avoid wild fish introduction, were simple and important measures that were implemented to prevent Anisakis and other parasites entering fish farms. The two complementary parts of this work, laboratorial activities used to support the fish supply chain, and the educational strategies concerning parasites, have made an essential contribution towards the availability of data for assessing and minimizing the level of risk associated with fish consumption, and have particularly increased and improved awareness, regarding foodborne parasites.