On 4 March 2015, McDonald’s USA announced that she will phase out chicken raised with human antibiotics at all its 14,000 U.S. restaurants within the next two years. Repeated and improper uses of human antibiotics in food animal production are blamed for increase in human drug-resistant bacteria.
However, the new antibiotics policy is not a total ban on the use of all antibiotics in chicken. McDonald’s suppliers are still allowed to use certain antibiotics to keep chickens healthy, provided that the drugs are not used for humans.
Use of Veterinary Drugs in Food Animal Farming
Animals, like human beings, may suffer from diseases and require proper drug treatment. Veterinary drugs (including but not limited to antibiotics) are mainly used to treat and prevent diseases in farmed animals. Animals receiving drug treatment may also grow faster and with leaner meat.
Many countries have specified the approved conditions for use of restricted veterinary drugs in food animals. On the other hand, some drugs (e.g. clenbuterol, chloramphenicol, etc.) are banned because of their high toxicities.
Problems Associated with the Use of Veterinary Drugs
Feeding food animals with veterinary drugs can leave residues in the meat, offal and other parts of the animals. Consumption of animal-derived foods containing residues can be detrimental to human health, depending on the nature of the veterinary drug, as well as the amount and duration of exposure.
For example, people who have consumed meat containing excessive clenbuterol residues (a prohibited lean-meat agent) may experience symptoms like rapid heart rates, dizziness, headaches, tremors and nervousness.
It is also noted that veterinary drug residues in foods may cause allergy and, not to mention, lead to development of pathogens with antibiotic-resistance.
Control of Veterinary Drug Residues in Food in Hong Kong
In order to protect consumer, many countries have set maximum acceptable levels of veterinary drugs in food i.e. maximum residue limits (MRLs). In Hong Kong, the Harmful Substances in Food Regulation (Cap.132AF) specifies MRLs of 39 chemicals possibly used in food animal farming. In addition, a zero-tolerance requirement is set for 7 highly toxic chemicals.
Importance of Food Surveillance and Testing
In modern food animal production, a total ban on the use of all antibiotics is not feasible. In this connection, foods of animal origin must be closely monitored for the presence of veterinary drug residues, in order to safeguard consumer health.
In Hong Kong, the Centre for Food Safety (CFS) is responsible for collecting food animal products from the markets for test of veterinary drugs. In 2013, the CFS collected ~ 350 samples of poultry products, and only one fresh chicken sample was found to contain residues of two veterinary drugs, Chlortetracycline and Oxytetracycline, at respective levels of 170 parts per billion (ppb) and 180 ppb, exceeding the legal limit of 100 ppb.
Apart from the government, other stakeholders along the food chain including farmers, manufacturers, importers, wholesalers and retailers also share the food safety responsibilities to periodically test foods of animal origin they produce / manufacture, import and sell.
Regular food testing is a proactive approach essential to ensure the food products meet the statutory requirements and are fit for human consumption.