Veterinary Drug Residues in Aquatic Products Supplied to Macao and their Safety


       According to recent news about the result of tests on samples of “Aquatic Products Used in Catering Service” within Guangdong released by Guangdong Food and Drug Administration, it mentioned that some of the aquatic products are found to contain prohibited substances, namely malachite green, chloramphenicol and nitrofurans. Since Macao and Guangdong are close neighbors, live aquatic products are largely imported to Macao from Mainland China.


       As aquatic products have always been one of the favorite food of Macao’s population, the following points serve to familiarize the public with knowledge about veterinary drug residues in aquatic products and their safety, laws and regulations governing the aquatic products supplied to Macao, respective notification mechanism and issues that the public and food sector should take note of.


Why these substances are prohibited for use on aquatic products?  

  • Malachite Green

It is a type of synthetic organic compound used as an industrial dye and bactericide which is effective for treating fish diseases. When malachite green is applied in fish farming, it penetrates into fish body tissues and produces metabolites that would persist in fish body for a long time. It is a potential carcinogenic chemical that could lead to developmental hazards. 

  • Chloramphenicol

Being a wide-ranging antibiotic, studies revealed that long-term intake of chloramphenicol causes human body to develop tolerance to some types of bacteria and serious adverse effects on the hematopoietic system to the extent of inhibiting the hematopoietic function of bone marrows.

  •  Nitrofurans

They are a class of chemical substances with a broad antibacterial spectrum that is effective in killing pathogens like fungi and protozoa. So far, there is evidence suggesting that nitrofurans might cause cancer in animals, pathologic changes in blood system, damages to the eyes, liver and kidneys.


What are the laws, regulations and notification mechanism available to safeguard the safety of aquatic products supplied to Macao?  

       According to current laws and regulations and import system governing aquatic products supplied to Macao, such products are subject to mandatory health inspection and quarantine before they are allowed for sale in local markets. If prohibited substances, namely malachite green, chloramphenicol and nitrofurans, etc., being part of the tested parameters, are found in these products during import inspection, IAM shall inform concerned departments of Mainland China immediately through the established cooperation and coordination mechanism while the import of these questionable products to Macao will be suspended until their food risk is removed. Moreover, Macao and the regulatory authorities on entry-exit inspection and quarantine of Mainland China have engaged in long-term cooperation schemes to jointly ensure the quality and safety of aquatic animals supplied to Macao for human consumption. Besides, according to “Food Safety Law” and as stipulated in Administrative Regulation no. 3/2016 dated 11 February 2016 which amended Administrative Regulation no. 6/2014 (List of Prohibited Substances for Use in Foodstuffs) dated 3 March 2014, malachite green, chloramphenicol and nitrofurans are classified as prohibited substances for use in foodstuffs. The food for sale in Macao must be free of these substances and any entity that has committed related offenses shall be punished according to the laws and regulations.


Advice for the food trade

  1. Ensure that the aquatic products for sale are suitable for human consumption and comply with laws and regulations of Macao;
  2. Purchase aquatic products from suppliers with reliable sources of supply;
  3. Safe keeping of invoice of purchases to facilitate future source tracing of products;
  4. Pay attention to announcements released by the Macao government and information about food safety. In case of necessity, take corresponding action to cope with the situation. 

Advice for the public

  1. Purchase aquatic products from reputable shops;
  2. Maintain a balanced diet, avoid excessive consumption of aquatic products or eating only one type of aquatic products to minimize risks involved;
  3. Wash, clean and cook aquatic products thoroughly before consumption;
  4. Should there be doubts about the safety of aquatic products, do not buy or consume them.