Content of sulphite in frozen prawns and shrimps

The contents of total sulphite in frozen prawns and shrimps were determined by the Monier–Williams procedure. The use of sulphites could be breaching legislative limits since the residues in the edible parts of some frozen prawns and shrimps samples were found to be higher than 150 mg SO2 per kg (maximum concentration admitted in the edible parts for these fresh and frozen products according to the current legislation). The non-edible parts presented much higher concentrations.