The highlights of the new regulation, passed by the local legislature in January, include a higher threshold for market access, a severe crackdown on businesses operating without a license, standardized online food operations and increased penalties.

The previous version of the regulation was issued in July 2011.

Chen Yin, deputy mayor of Shanghai, said during a news conference on Friday that the regulation imposes the strictest market-access standards, but will be enforced with a problem-solving approach to improve supervision of food producers, force all parties involved to carry out their responsibilities and tackle outstanding problems in the food safety sector.

A three-level supervision and coordination mechanism at the city, district and township levels will be set up.

Shanghai also unveiled an action plan on Friday to make it a city whose residents are fully satisfied with the level of food safety.

A total of 14,000 food service licenses had been withdrawn or revoked in 2016, with 163 million yuan ($28 million) confiscated in 7,240 cases involving illegal activity related to food, official figures showed.

A total of 320 suspects have been apprehended, and 129 of them were taken to court last year.

One question being asked by the public in Shanghai is whether Japanese retailer Muji had been selling food affected by the Fukushima nuclear disaster in 2011. Yan Zuqiang, head of the Shanghai Food and Drug Administration, reiterated on Friday that no nuclear-contaminated food has been found in the city.

In a report issued on 15 March - World Consumer Rights Day - China Central Television reported that food from areas affected by the nuclear disaster had been sold on many e-commerce platforms in China and in some brick-and-mortar shops, including Muji.

The city's entry-exit inspection and quarantine department and the administration had intensified their examinations, but no problems had surfaced, Yan said.

He also said that in 2016, food possibly contaminated by radioactive elements, including fruits, vegetables, dairy and aquatic products was a focus of the inspections, but that all the samples that were tested met China's standards.