The Agricultural Chemicals and Veterinary Drugs Unit (the Unit) under the Slaughterhouse (Veterinary) Section enforces the Public Health (Animals and Birds) (Chemical Residues) Regulation (Cap. 139N) (the Regulation). Feeding of drugs and chemicals to food animals can leave residues in meat, offal and other parts of the animals and there may be food safety concern when tissues containing prohibited chemicals or tissues containing residues of restricted chemicals exceeding the maximum residue limits (MRLs) are consumed. The Unit conducts monitoring and surveillance programmes on residues of agricultural chemicals and veterinary drugs by collecting samples from food animals in the slaughterhouses for testing. 
 
Seven prohibited chemicals including two antibiotics, two beta-agonists and three hormones are listed in the Regulation. These chemicals are prohibited because of their possible harmful side effects in humans.

A total of 37 restricted chemicals are listed in the Regulation and they are antibiotics or antiparasitic agents. The MRLs of these restricted chemicals in the tissues of food animals are set under the Regulation.

Sampling and Testing on Residues of Agricultural Chemicals and Veterinary Drugs

Urine samples are collected from every batch of pigs admitted into the slaughterhouses in Hong Kong for testing of residues of agricultural chemicals and veterinary drugs. If the samples are found to contain prohibited chemical residues, the implicated batches of pigs in the slaughterhouses would be withheld from entering the food chain and destroyed.

Different samples including urine and tissues are collected by the Unit for laboratory testing each year.