Metagenomic evaluation of the effects of storage conditions on the bacterial microbiota of oysters Crassostrea gasar (Adanson, 1757)

Abstract

Aims: To evaluate the influence of storage conditions on the composition of the bacterial microbiota of living oysters Crassostrea gasar.

Methods and results: The oysters used in this study came from marine farms (Guaratuba Bay, Brazil) and were exposed to two conditions that simulated different storage situations: immersion in water (group I) and exposure to air (group II). The animals were subjected to five different temperatures (5-25°C), for 10 days. The 16S rRNA gene from oysters was amplified and sequenced to determine the taxonomic units and bacterial strains present in the samples. Group I showed higher diversity of bacteria (163 genera) rather than group II (104 genera). In all, 59 bacterial genera potentially pathogenic to humans were identified (n = 56 in group I and n = 45 in group II).

Conclusions: The storage conditions having a direct influence on the oyster microbiota. Live C. gasar should be stored exposed to air at 5-25°C, because it favours a lower prevalence of bacteria potentially pathogenic to humans.

Significance and impact of the study: During the oyster commercialization process, some conditions of storage, time and temperature must be followed in order to reduce the prevalence of bacteria potentially pathogenic to humans.

Keywords: food safety; foodborne diseases; mollusks; oyster quality; oyster storage; temperature.