Hong Kong is probing McDonald's to find out if the fast-food company knowingly sold products made from tainted meat from China.

The South China Morning Post reported that the Hong Kong Centre for Food Safety is conducting a probe into the matter.

The watchdog said samples collected during 48 visits to various fast-food chains, including McDonald's, Pizza Hut, Yoshinoya and Burger King were tested as safe.

However, it had seized 59 tonnes of Shanghai Husi Food products imported from China, all from McDonald's.

McDonald's earlier acknowledged it imported raw meat from Shanghai Husi Food that is accused of reprocessing and repackaging rotten meat.

Hong Kong Food safety officials suspect that the acknowledgment came only after the government suspended all Husi imports originating from China.

When the scandal broke out in China earlier this week, McDonald's Hong Kong said its products are safe. However, it admitted on 24 July that it imported chicken and pork from the Shanghai plant, and suspended sales of products including chicken nuggets and McSpicy burgers.

"The information McDonald's announced to the public on Monday and then changed [on Thursday] is contradictory," Hong Kong's Democratic Party deputy consumer rights spokesman, Andrew Chiu Ka-yin, told the newspaper.

"Consumers have based their decisions on whether to eat at McDonald's this week based on the Monday statement. The Monday announcement was reflected to the public by all the media, but it was incorrect information."

The Chinese local media earlier reported that Shanghai Husi Food, owned by US-based OSI Group, sold chicken and beef past their expiry dates to international food chains including McDonald's, KFC and Pizza Hut.

Subsequently, Shanghai's Food and Drug Administration conducted a raid at the firm's facilities and seized more than 5,000 boxes of expired meat. In addition, police detained five employees at the firm, including its quality manager.

Nine companies including KFC, McDonald's, Burger King and Papa John's have used products from Shanghai Husi. Following the outbreak of the scandal, the companies apologised to Chinese customers and said they were taking the products concerned off the shelves.

McDonald's has been one of the hardest-hit companies from the scandal, as it had to stop selling products in Japan and Hong Kong, in addition to China.