Depuration processes affect theVibriocommunity in the microbiota of the Manila clam,Ruditapes philippinarum

As filter-feeders, bivalve molluscs accumulateVibriointo edible tissues. Consequently, an accurate assessment of depuration procedures and the characterization of the persistentVibriocommunity in depurated shellfish represent a key issue to guarantee food safety in shellfish products. The present study investigated changes in the naturalVibriocommunity composition of theRuditapes philippinarummicrobiota with specific focus on human pathogenic species. For this purpose, the study proposed a MLSA-NGS approach (rRNA 16S,recA andpyrH) for the detection and identification ofVibriospecies. Clam microbiota were analysed before and after depuration procedures performed in four depuration plants, using culture-dependent and independent approaches. Microbiological counts and NGS data revealed differences in terms of both contamination load andVibriocommunity between depuration plants. The novel MLSA-NGS approach allowed for a clear definition of theVibriospecies specific to each depuration plant. Specifically, depurated clam microbiota showed presence of human pathogenic species. Ozone treatments and the density of clams in the depuration tank probably influenced the level of contamination and theVibriocommunity composition. The composition ofVibriocommunity specific to each plant should be carefully evaluated during the risk assessment to guarantee a food-safe shellfish-product for the consumer.