Study of the efficacy of three depuration methods as a prerequisite for the hygiene-sanitary program in bivalve molluscs, from mariculture in Jurujuba, Niterói, Brazil

Abstract

Depuration is a technique used to reduce microbial contamination of filtering molluscs, to levels acceptable by legislation for human consumption, by keeping the animals in tanks with clean water. The present study aimed to verify the effectiveness of three depuration methods on Perna mussels (Linnaeus, 1758), from commercial cultivation in Jurujuba, Niterói, Rio de Janeiro, Brazil, as a prerequisite for the National Safe Bivalve Molluscs Program (MoluBiS) aiming to satisfactory microbiological quality in bivalve molluscs. The depuration systems used were closed recirculated seawater systems with disinfection methods that use ozone, ultraviolet light (UV) and UV light associated to a chlorine-based compound. Thus, 80 animals were collected at once for experimental contamination with a strain of Escherichia coli, application of the three different depuration methods and subsequent bacteriological analysis of the mussels. After statistical analysis of the results, it was observed that in the depuration process using ozone for 10 min with 3.05 log, ultraviolet (UV) with 2.20 log, and ultraviolet (UV) combined with a sanitizing agent with 2.08 log, there was inactivation of E. coli in a relatively short time (24 h), allowing for the commercial sale of this mollusk in a reduced time. Therefore, it is necessary to implement depuration processes in the state of Rio de Janeiro to monitor sanitary conditions, so that the minimum requirements for guaranteeing the safety and quality of bivalve molluscs for human consumption are ensured.