A McDonald's store in Wuhu, Anhui Province. [Photo /Xinhua]

Chinese diners may have to wait until 2027 to enjoy nuggets free of a certain antibiotics at McDonald's as the country is not among the markets where the chemical will be banned before that.

In a statement released on Wednesday, the fast food chain announced that it will begin implementing a new broiler chicken antibiotics policy in markets around the world, which require the elimination of antibiotics defined by the WHO as Highest Priority Critically Important (HPCIA) to human medicine.

By January 2018, HPCIAs will be eliminated at McDonald's outlets in Brazil, Canada, Japan, South Korea, the United States and Europe, with an exception for Colistin for Europe only, the company said.

The ban will be expanded to Australia and Russia by the end of 2019. HPCIAs will be rooted out in other markets, including China, by January 2027.

Besides, the company will develop related policies for suppliers providing beef, dairy cows, pork and laying hens, the statement added.

Responding to why China is not on the list, McDonald's said in a note to Global Times newspaper that the company has adhered to its global goal of eliminating use of antibiotics in Chinese market, and "has worked closely with relevant government department, suppliers, industry associations and scholars to promote the industry's sustainable development".

The company said the food safety concept of McDonald's China is consistent with the world's.

Taking the feeding of poultry as an example, the birds must take proper antibiotics during treatment of diseases, and suppliers conduct medication under the guidance of veterinarians. Besides, the type, usage and dosage of medicine are strictly in line with China's related laws and regulation, the note said.

Antibiotics have long been used on factory farms to prevent disease outbreaks and speed the growth of animals.

But research shows the overuse of antibiotics in livestock also contributes to the development of superbugs—bacteria that are immune to the effects of even multiple antibiotics.