Comparative analysis of the efficiency of different commercial depuration systems and the evaluation of species-specific depuration conditions in bivalve mollusc production

Abstract

This study assesses and compares the efficiency of three commercial depuration systems for live bivalve mollusc production. Ruditapes philippinarum (Rp), Ruditapes decussatus (Rd), Donax trunculus (Dt), and Venus verrucosa (Vv) were used as research materials to evaluate full open (FO), semi-closed (SC), and closed cycle (CC) systems. Results reveal a logarithmic decrease in Escherichia coli levels during the initial six hours across all species. Rd achieved full depuration after 12 hours in the CC system and 24 hours in the FO system; Vv required 18 hours, while others needed up to 24 hours. At the 4600 MPN/100 g level, the CC system fortified by an ozone generator showed the most efficient depuration with the following results: 18 hours for Rp and Vv, 24 hours for Rd, and 36 hours for Dt. The SC system prolonged depuration times for all species. Species-specific filtration behaviour emerged as a crucial factor during contamination and depuration rates. Statistical analysis highlighted pH, dissolved oxygen, and salinity as key parameters influencing depuration efficiency, with temperature showing lesser significance compared to other variables for effective species-specific system design. This study focuses on identifying the parameters affecting the depuration characteristics of different bivalve species and commercial systems, and predicting the effects of potential changes. The findings are expected not only to enhance scientific understanding in this field but also to contribute to the system designs and adaptation of existing businesses to various conditions.