Routine use of antibiotics in animals can contribute to the rise of drug-resistant pathogens - or "superbugs" - that are responsible for killing at least 23,000 people a year in the US and represent a significant threat to global public health, according to a report by the BBC.

Li Shuguang, a public health expert at Fudan University in Shanghai, said excessive use of antibiotics can cause bacteria to mutate more quickly and become resistant, and could, in turn, result in superbacteria that are resistant to virtually all drugs. This could pose a significant threat to humans, he said.

Like many other countries, China has rules restricting the use of antibiotics in livestock, both in type and quantity, he said, so the decision by McDonald's to continue using antibiotics in China is not against law, but its processes must comply with the regulations.

China has stricter standards than the United States in some areas, such as the use of clenbuterol, a drug used to increase the muscle mass of livestock.

Every year, 50 percent of the antibiotics used worldwide are used in China. And 52 percent of those are used to treat animals bred for food, according to a report on international antibiotic use led by Jim O'Neill, former chief economist at Goldman Sachs.

Wang Zhuoqiong contributed to this story.