Norovirus contamination of sea urchins (Paracentrotus lividus): Potential food risk for consumers

Sea urchin gonads are today considered a gourmet food but despite eaten raw, not much attention has been given to microbiological quality. This study evaluated the microbial (bacterial and viral) contamination and adequacy to current European regulations of Paracentrotus lividus sea urchins produced in Portugal.Four batches of 10 sea urchins were collected (September 2016 to May 2017) from the sea floor of a natural urchin growing area located in the north of Portugal. Sea urchin gonad batches were analysed for E. coli and Salmonella spp. as governed by the Commission Regulation (EC) No 2073/2005, modified by regulation (EC) No 2015/2285, on microbiological criteria for foodstuffs. Hepatitis A virus, norovirus GI and norovirus GII were also searched for following ISO 15216-1:2017.The four batches were all within the sanitary limits imposed by legislation for E. coli and Salmonella spp. Two batches were found positive for norovirus (one positive for norovirus GI, the other for both norovirus GI and GII), presenting viral concentrations that ranged from 8.7 × 103 and 3.2 × 104 genome copies/g. Sequencing and phylogenetic analysis showed that the obtained sequence clustered with norovirus GI.2.This study is the first evaluating the presence of human pathogenic viruses in live echinoderms and the first reporting NoV contamination of bacteriologically safe sea urchin gonads. NoV infection risk related to consumption of raw sea urchin gonads is in urgent need for evaluation.