Professor Thomas Y.K. Chan, Director of the Centre for Food and Drug Safety, and Professor H.S. Kwan, Acting Dean of Faculty of Science, The Chinese University of Hong Kong presented today the latest published data on the health risk associated with fish-borne malachite green and the recommendations of food safety agencies from other western countries.

Eels are much more likely to accumulate malachite green and metabolite leucomalachite green than other fresh water fish, for two main reasons. Eels are scaleless, allowing easy absorption of malachite green through the skin. Fat content of muscle tissues accounts for as much as 25% of the weight of eels. Malachite green and particularly leucomalachite green tend to accumulate in fat tissues, especially the internal viscera. The public must not regard other fresh water fish as having similar risk potential as eels. They should not eat the internal viscera of fish.

Animal studies and in-vitro experiments indicate that malachite green and leucomalachite green might have the potentials to cause tumours, mutations and chromosomal abnormities. With the availability of safer alternatives, many countries have banned the use of malachite green in food fish.

Malachite green contamination in fish is classified as a Class II Health Hazard in Canada, i.e. the probability of adverse health consequences is remote. Short-term exposure to low malachite green levels is not a health risk to consumers. Some experts estimate that to have any ill effects, a person has to consume daily more than 2,000 pieces of 250g fresh water fish with low malachite green levels over a long duration.

Several measures should help assure food safety in Hong Kong, including the establishment of a food safety centre and an independent food safety agency to provide expert advice to the Government and the public.