China's food regulator has visited 600 fast food outlets and food distributors over fears out-of-date or rotten meat is being sold for consumption, the watchdog said in a statement.
Big chains like McDonald's, Starbucks and KFC-parent group Yum Brands Inc have already been dragged into the safety scare.
The investigation comes after five people from OSI Group, the US parent of China-based meat-processing factory at the center of the incident, were arrested. Yum has now severed ties with the group.
More top news
Coronation Street actor Ryan Thomas is to quit the show after more than 15 years.
Fresh violence has erupted in the West Bank following the death of a 13-year-old boy, sparking fears of a new Palestinian uprising.
A family dog was 'best man' as he stood by a wounded veteran's side when he married his school sweetheart.