"The central government has attached high importance to the prosperity and stability of Hong Kong and the well-being of its residents, and has made great efforts to ensure the safety of food and agricultural products supplied to Hong Kong over the past 20 years," said China's General Administration of Quality Supervision, Inspection and Quarantine in a release.

The Chinese mainland has been a major source of food and agricultural products for Hong Kong, with almost all live pigs, beef and vegetables in Hong Kong markets supplied by the mainland, according to the administration.

More than 99.7 per cent of food supplied by the Chinese mainland to Hong Kong is up to standard, and no serious food safety incident has ever happened in Hong Kong involving such products in the past 20 years, the administration said.

Of the 300 types of products supplied to Hong Kong, many are local delicacies, such as chickens from Hainan province and crabs from Yangcheng Lake in Jiangsu province.

Guangdong province, which neighbors Hong Kong and is a major source of food and agricultural products for the city, has supplied more than 30 million tons of such products to Hong Kong over the past 20 years, according to the Guangdong Exit-Entry Inspection and Quarantine Bureau.

For instance, the province supplies Hong Kong with about 150,000 eggs and more than 2,700 live pigs every day, with the value of food and agricultural products supplied to Hong Kong by Guangdong totaling nearly $2.3 billion every year, the bureau said.

In order to ensure the safe, smooth and stable supply of food and agricultural products to Hong Kong, related inspection and quarantine authorities in the province are on duty 24 hours a day, it said.

To ensure the safety of food supplies, inspection and quarantine authorities on the mainland invest nearly 100 million yuan ($14.74 million) every year on the monitoring of animal and plants for health and safety, the General Administration of Quality Supervision, Inspection and Quarantine said.

Authorities on the mainland have established close cooperation with their counterparts in Hong Kong to ensure the safety of products. They also impose strict supervision on enterprises that produce food for Hong Kong, and severely punish violators of food safety laws, according to the administration.

All producers and processing companies for food and agricultural products supplied to Hong Kong are monitored by the inspection and quarantine authorities on the mainland, which covers the whole process including production, selling and distribution to ensure food safety, Zhi Shuping, head of the administration, said at a news conference during the annual session of the National People's Congress, China's top legislature, in March.

Inspection and quarantine authorities have also opened "priority corridors" for food supply to Hong Kong, so enterprises supplying fresh food to the city do not have to wait for inspection and quarantine of their goods, even during holidays and at night.

Meanwhile, authorities on the mainland have also adopted digital technologies for more effective supervision so information on major products supplied to Hong Kong, such as their origin, production and transport details, are traceable.

The administration will continue to improve supervision over the safety of food provided to Hong Kong from the mainland, and intensify cooperation with related departments in Hong Kong to ensure the safety of food and agricultural products supplied to the city, it said.