Analysis of microbiota in whole body of sea cucumber (Apostichopus japonicus) from South Korea for seafood management

The consumption of sea cucumber (Apostichopus japonicus) have been increased due to its medicinal properties and seafood source in Asia including South Korea. The ingestion of raw sea cucumber can cause foodborne illness by various microbes in it. Therefore, analysis of the microbiota in the whole body of sea cucumber can extend our understanding of foodborne illness by microorganisms and help to better manage products. Here, we collected 40 sea cucumbers from four different sites in August and November, which are known as the maximum production area in Korea. The microbiota were analyzed by Illumina Miseq system, and bacterial amounts were quantified by real-time PCR. The diversity and bacterial amounts in sea cucumber were higher in August samples than those in November samples. Alpha-, Beta-, and Gammaproteobacteria were common dominant classes in all samples. However, the composition of microbiota was different according to sampling time and sites. Staphylococcus warneri was commonly detected potential pathogens in August samples and Propionibacterium acnes was in November samples. The effect of Vibrio parahaemolyticus infection on the indigenous microbiota of sea cucumber was analyzed at different temperature conditions. The alterations of Psychrobacter and Moraxella can be used as indicators of monitoring infection of sea cucumber. Although further studies are needed to clarify and understand the virulence and mechanisms of these results, our study can be used to understand the potential of foodborne illness caused by sea cucumber ingestion and to develop monitoring products using microbiota information.