Contents lists available at ScienceDirect Food Microbiology journal homepage: www.elsevier.com/locate/fm Bacterial communities and potential spoilage markers of whole blue crab (Callinectes sapidus) stored under commercial simulated conditions F.F. Parlapani a,* , S. Michailidou b , D.A. Anagnostopoulos a , S. Koromilas a , K. Kios a , K. Pasentsis b , F. Psomopoulos b , A. Argiriou b , S.A. Haroutounian c , I.S. Boziaris a a Lab. Marketing and Technology of Aquatic Products and Foods, Dept. of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fitokou street, 38446, N. Ionia, Volos, Greece b Institute of Applied Biosciences, Centre for Research and Technology Hellas (CERTH), 57001, Thessaloniki, Greece c Department of Animal Science and Aquaculture, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece ARTICLE INFO Keywords: Blue crab Seafood 16S next-generation sequencing (NGS) Microbiota VOCs Spoilage markers ABSTRACT Bacterial communities composition using 16S Next Generation Sequencing (NGS) and Volatile Organic Compounds (VOCs) profile of whole blue crabs (Callinectes sapidus) stored at 4 and 10 °C (proper and abuse temperature) simulating real storage conditions were performed. Conventional microbiological and chemical analyses (Total Volatile Base-Nitrogen/TVB-N and Trimethylamine-Nitrogen/TMA-N) were also carried out. The rejection time point was 10 and 6 days for the whole crabs stored at 4 and 10 °C, respectively, as determined by development of unpleasant odors, which coincided with crabs death. Initially, the Aerobic Plate Count (APC) was 4.87 log cfu/g and increased by 3 logs at the rejection time. The 16S NGS analysis of DNA extracted directly from the crab tissue (culture-independent method), showed that the initial microbiota of the blue crab mainly consisted of Candidatus Bacilloplasma, while potential pathogens e.g. Listeria monocytogenes, Pseudomonas aer- uginosa and Acinetobacter baumannii, were also found. At the rejection point, bacteria of Rhodobacteraceae fa- mily (52%) and Vibrio spp. (40.2%) dominated at 4 and 10 °C, respectively. TVB-N and TMA-N also increased, reaching higher values at higher storage temperature. The relative concentrations of some VOCs such as 1-octen- 3-ol, trans-2-octenal, trans,trans-2,4-heptadienal, 2-butanone, 3-butanone, 2-heptanone, ethyl isobutyrate, ethyl acetate, ethyl-2-methylbutyrate, ethyl isovalerate, hexanoic acid ethyl ester and indole, exhibited an increasing trend during crab storage, making them promising spoilage markers. The composition of microbial communities at different storage temperatures was examined by 16S amplicon meta-barcoding analysis. This kind of analysis in conjugation with the volatile profile can be used to explore the microbiological quality and further assist towards the application of the appropriate strategies to extend crab shelf-life and protect consumer's health. 1. Introduction Callinectes sapidus is an allochthonous crab species originated from the West Atlantic Ocean which probably colonized Greek coastal areas, especially the Thermaikos Gulf, in 1940 (Serbetis, 1959). Although, for many decades the population of blue crab remained at low numbers, an unexpected increase was recorded in 2009 (Kevrekidis, 2010) which resulted in a noteworthy increase of the population to date. The in- crease of blue crab population has reinforced the local economy as well as created new jobs and export opportunities. Local fishermen transfer the caught blue crabs to seafood companies for further handling and/or processing. The healthy, live crabs are placed in baskets for direct sale or they are stored in water tanks in order to survive for longer periods of time and be sold at a later date. Blue crabs are sold live or frozen to retail seafood markets, hotels and restaurants in Greece, other Eur- opean countries and Asia e.g. Japan. In contrast to other seafood, crabs are usually transported and dis- tributed alive stored at 4–8 °C (Jacklin and Combes, 2007). Crustaceans have the ability to survive out of the water for an extended period of time. Nevertheless, due to the fact that they cannot keep their gills moist, damage can occur to their gills as a result of oxygen reduction which can eventually lead to death (Jacklin and Combes, 2007). Crabs can be stored alive in domestic and commercial refrigerators at 4 °C. The chill-stored crabs become unacceptable (characterized as ‘spoiled’) for human consumption when still alive (Robson et al., 2007). Crabs and other crustaceans spoilage is mainly due to the microbial growth https://doi.org/10.1016/j.fm.2019.03.011 Received 10 August 2018; Received in revised form 7 March 2019; Accepted 7 March 2019 * Corresponding author. School of Agricultural Sciences, Dept of Ichthyology and Aquatic Environment, Fitokou street, 38446, N. Ionia, Volos, Greece. E-mail address: fwparlap@uth.gr (F.F. Parlapani). Food Microbiology 82 (2019) 325–333 Available online 13 March 2019 0740-0020/ © 2019 Published by Elsevier Ltd. T