China's food regulator has visited close to 600 restaurants, businesses and food distributors, the watchdog said in a statement, in an investigation into a fast-spreading food safety scare.
The safety scare has already dragged in U.S. chains McDonald's Corp, KFC-parent Yum Brands Inc and coffee giant Starbucks Corp.
Yum severed ties with OSI Group, the U.S. parent of the China-based meat-processing factory at the centre of the incident, after Shanghai police detained five people from the facility on Wednesday.