Police in western China detained 11 people after a crowd of angry customers in early May smashed a halal shop suspected of mishandling food prepared according to Islamic custom, state media said.

A group of "law-breakers" in Xining, the capital of Qinghai province, broke into a store on May 1 and vandalized it after discovering that non-halal foods had been transported along with halal products, a violation of regulations.

An investigation by authorities revealed that suspicions that sausages had been sold at the store were not true, state-run Xining Television reported on Friday.

The owner made "sincere apologies" to the store's Muslim customers, the report said, adding that it was ordered to stop selling, transporting and producing halal products and received a fine.

It said the owner, surnamed Li, belonged to the Hui Muslim minority and that most of the store's staff were Muslim.

Food safety and quality remains a major concern in China after a series of high-profile scandals.

Wang Zuoan, the head of China's State Administration for Religious Affairs, said in an interview published on Sunday in the ruling Communist Party's Study Times, that China must "protect the legal interests of religious groups.”

China has struggled to tame unrest among some Muslims, particularly in its western Xinjiang region, home to ethnic Uighurs, many of whom chafe at the government's strict controls on religion.

(Reporting by Michael Martina; Editing by Kim Coghill)