The accuracy of visual inspection for preventing risk of Anisakis spp. infection in unprocessed fish

The importance of the zoonoses caused by L3 Anisakidae larvae lies in the repercussion that this parasite 22 exerts on food safety and quality. EU legislation recommends fish operators to do visual inspection of the 23 whole fish abdominal cavity and gut to control the risk of visible parasites, thus ensuring that no 24 contaminated fish reach the consumers. The accuracy of the above visual inspection method should fall 25 on a well-tested statistical significance between the number of observable parasites in the abdominal 26 cavity and the number of parasites in the edible part of the fish (i.e., musculature). The aim of this study 27 was to analyse this statistical significance, and the efficacy of the washing practice to remove Anisakis 28 spp. from gut. To carry out this work, 322 fresh individuals of Micromesistius poutassou and 230 of 29 Scomber scombrus were necropsied within 12 hours and 48 hours post-capture. Then, descriptive 30 statistics, correlation and regression analyses were used to evaluate the significant statistical relationship 31 between the number of anisakid larvae found in the gut and musculature of both fish species. 32 Additionally, livers and gonads of 25 fresh specimens of Merluccius merluccius were vigorously washed 33 under tap water, and examined under stereomicroscope looking for Anisakis spp. larvae. Results 34 evidenced the low efficiency of visual inspection of gut parasites as a commonly recommended method 35 for predicting nematode larvae in the flesh of fish. Therefore, a direct-invasive inspection of musculature 36 is stressed as the only criteria with scientific merit for accurately detecting contaminated fishes by 37 anisakids. Moreover, fresh European hake liver and gonads showed at least one larva remained inside the 38 tissue after washing vigorously under tap water. Results suggested that critical control points at Hazard 39 Analysis Critical Control Point (HACCP) programmes should be reviewed to improve the risk of 40 anisakid-induced allergies and gastrointestinal anisakiasis among consumers.

Xunta de Galicia has provided financial support for this work under the Project INCITE- 227 44.02.741A.771.0. María Llarena-Reino thanks Fundação para a Ciência e a Tecnologia for financial 228 support under Grant SFRH / BD / 45398 / 2008.

Peer reviewed