Growth, nutritional quality and safety of oysters (Crassostrea gigas) cultured in the lagoon of Venice (Italy)

Quality aspects of oysters (Crassostrea gigas) from a suspended culture in the lagoon of Venice (Valle Doga) were examined in different seasons over a 1-year period. Ecophysiological and commercial quality indicators (condition index, content of meat, shell and intervalvar fluid), nutritional quality parameters (proximate and mineral composition, glycogen content, fatty acid profile, cholesterol, plant sterols, fat-soluble vitamins content) and levels of organic: pollutants (polychlorinated biphenyls and organochlorine pesticides) were determined at different times of the year. Seasonal variations were observed in the nutrient content, with particular regard to moisture (ranging from 866.8 g kg(-1) in June to 938.8 g kg(-1) in September), protein (23.9 g kg(-1) in September to 76.6 g kg(-1) in June), ash (22.5 g kg(-1) in February to 29.5 g kg(-1) in July), lipid (3.0 g kg(-1) in September to 8.8 g kg(-1) in June) and glycogen (0.7 g kg(-1) in September to 11.5 g kg(-1) in February). In spite of this variability, the nutritional quality of the oysters was generally good, especially just before gamete release when the concentration of nutrients was at its maximum. Low levels of organochlorine chemicals were detected in the edible meat of oysters but, because only a limited number of samples were analysed, no general conclusion can be drawn on the safety of seafood from this area. (C) 2004 Society of Chemical Industry.