Hong Kong's Centre for Food Safety announced on 22 October 2026 that malachite green had been detected in a sample of bluefin tuna. The sample was collected at import level under the centre's routine Food Surveillance Programme, and testing showed a level of 1.74 parts per billion, a spokesman said. The centre said it had informed the importer of the irregularity and was tracing the product's source and distribution.

Malachite green is an industrial dye that has been used to treat infections in fish, and it is currently prohibited for use in food-producing animals in many countries. Under the Harmful Substances in Food Regulations (Cap. 132AF), no food sold in Hong Kong may contain the substance; offenders face prosecution, a fine of $50,000 and six months' imprisonment on conviction.

The centre said it would continue to follow up and take appropriate action. Its investigation was ongoing as of the announcement.