Expired dough used in Nanjing branch of US-based restaurant Papa John's Pizza

A Nanjing branch of the popular US-based fast-food restaurant Papa John's Pizza has been found to have used expired dough.

Inspectors found pizza base in the restaurant that should have been discarded two days earlier, a spokesman for the company confirmed.

The report comes amid intense scrutiny of food suppliers on the mainland after Husi Food Company, the Shanghai subsidiary of a United States-based meat supplier, was accused of selling expired meat to international restaurant chains including McDonald's and Papa John's.

The pizza restaurant in Nanjing has been closed down while an investigation is being carried out by the food and drug administration, the Jinling Evening News reported.

Papa John's spokesman Zhang Lie said the matter was a one-off incident and that staff at the restaurant would be disciplined for breaching company regulations.

"We are shocked to hear the news. It's not acceptable," Zhang said. "The Husi incident has dealt a heavy blow to the entire catering industry, but [the expired dough] is the problem of an individual store."