Food Safety Focus (64th Issue, November 2011) – Food Incident Highlight
Copper in Oyster
Last month, according to the media, research conducted in the Mainland reported high levels of copper might be present in oysters from the Pearl River Delta which raised public concerns. In view of the media reports, the Centre for Food Safety had taken some oyster samples from the local market. Risk assessments on the low copper levels detected showed that they were not of food safety concern.
Copper is a metallic element occurring naturally throughout the environment and also widely distributed in the body. It is an essential nutrient incorporated into enzymatic and structural proteins involved in many critical metabolic processes including the formation of haemoglobin. Human diet must supply regular amounts for absorption. Copper poisoning is uncommon except in accidental or deliberate ingestion of large quantities of copper salts and in cases related to disorders in copper metabolism or liver disease.
Under Codex General Standard for Contaminants and Toxins in Food and Feed, copper is not considered as a contaminant with public health significance hence no copper standard is required. In the Mainland, tolerance limits of copper in foods (GB15199–94) for aquatic products (e.g. oysters), beans, fruits, etc have been repealed on 10 January 2011.