Monitoring of spoilage and determination of microbial communities based on 16S rRNA gene sequence analysis of whole sea bream stored at various temperatures

Abstract

Exploration of initial and spoilage microbiota grown on plates of whole sea bream stored aerobically at 0 (ice), 5 and 15 °C, was conducted by 16S rRNA gene sequence analysis. The course of spoilage was recorded by monitoring microbiological, sensory and chemical changes. Shelf-life of sea bream determined by sensory assessment was 16, 5 and 2 days at 0 (ice), 5 and 15οC, respectively. Pseudomonas spp. was the dominant spoilage population of whole sea bream at all temperatures tested. A sum of 144 colonies were isolated from TSA (Tryptone Soy Agar) plates and identified by genotypic approach at the beginning and at the sensory rejection time points. Regarding initial microbiota, Pseudomonas fragi was the most abundant compared to the rest bacteria (Pseudomonas fluorescens, Enterobacter hormaechei, Chryseobacterium carnipullorum). P. fragi was also the dominant microorganism of fish stored at 0 and 5, while P. fluorescens at 15 οC. Concluding, genotypic approach gives accurate identification of the dominant spoilage microorganisms providing us with valuable information regarding microbiological spoilage of fish.