China's food regulator has visited 600 fast food outlets and food distributors over fears out-of-date or rotten meat is being sold for consumption, the watchdog said in a statement.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.
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