Recently, the media reported that fan scallops being sold in local markets and restaurants were found to be contaminated with cadmum and this has raised public concerns.
Cadmium is a metallic element that occurs naturally in the Earth's crust. It can also be released to the environment by human activities. Fertilisers produced from phosphate ores and industrial operations such as mining are important sources of environmental cadmium contamination. Plants, animals, fish and shellfish will take up cadmium when grown in contaminated environment (soil, air, water, fertilizers, feeding stuffs, etc). Acute toxicity of cadmium due to dietary exposure is very unlikely but prolonged excessive intake of cadmium may have adverse effects on the kidneys.
In Hong Kong, there is a robust control system on food import. The Centre for Food Safety (CFS) has been conducting routine surveillance for heavy metals including cadmium in foods collected from import, wholesale and retail levels. In the year of 2012, 68 samples of scallop had been taken for testing of cadmium. The results were satisfactory.
For those food items for which Codex Alimentarius does not have an established standard, like the level of cadmium in scallop, the CFS generally conducts risk assessment to determine the potential health risk to the public.
Members of the public are advised to patronise reliable shops when buying seafood and maintain a balanced diet to minimise food risk. In addition, when consuming any shellfish, it is advised to remove the viscera before cooking as the concentration of heavy metals, shellfish toxins and microbes are generally higher in the viscera of contaminated shellfish.
The CFS will remain vigilant to the development of the incident.