Acompanhamento da dinâmica de depuração de ostras (Crassostrea rhizoporae) e água de estuário: perspectiva na diminuição dos coliformes termotolerantes

Abstract

Oysters are filter-feeding bivalve molluscs, which feed on suspended particles present in the water, and can act as vectors of pathogenic microorganisms that can affect human health. In this way, purification is a widely used practice that aims to eliminate pathogenic agents from bivalve molluscs, providing a product with a health guarantee to the consumer. Therefore, the present study aims to evaluate the microbiological quality of oysters (Crassostrea rhizophorae) and cultured water in the Cocó River Estuary, in the State of Ceará. 170 oysters of the Crassostrea rhizophorae species were collected while still alive and placed in a tank with a disinfection process using UV light. As a result, it was possible to reduce the bacterial load in the muscles and in the liquid interval over the course of two days. Initially, 26 MPN/g were found in the muscle and 21MPN/ml in the intervalvar fluid and at the end the counts were < 1.8 MPN/g and < 1.8 MPN/ml, respectively. Of 173 strains isolated, 135 strains were confirmed as being of the Escherichia coli species. Of these, 122 strains were sent for the antibiogram, 27 coming from the oyster muscle, 60 from the intervalvar liquid and 35 from water samples from the estuary at the time of oyster collection. The muscle strains were those that showed the highest number of resistance, followed by strains from the intervalvar liquid and water samples.The purification system was efficient in reducing microorganisms, however the resistance found, even in small quantities, requires care, due to the fact that resistant bacteria can be passed on to humans.