Fast food chain probes reports of doctored expirations

US fast food chain Subway is investigating media reports in China that workers at a Beijing outlet doctored food labels and used produce beyond its expiration date, a spokeswoman for the company said in Shanghai on Monday.

Chinese media reports that started to appear on Friday said workers at the outlet changed expiration and production dates on meat, drink and vegetable produce to extend their use.

"Our headquarters here is now investigating the matter," the Subway spokeswoman said, adding that the company had not reached any conclusions.