More troubles for McDonald's and Yum! Brands' KFC in China as they face a new food safety scandal in one of their largest international markets. Both fast food giants apologized on Monday to Chinese consumers after local television showed workers at a meat supplier picking up meat from the factory floor and also mixing expired meat with fresh meat. Both McDonald's and KFC say they will stop using the supplier. KFC was the first quick-service restaurant chain to enter the China market back in 1987 and now has more than 4,600 outlets across the country. The latest food safety scandal comes just two years after both fast food companies had to deal with another food safety issue. The latest incident highlights the difficulty in ensuring safety and quality along the food supply chain in China. TheStreet's Ruben Ramirez reports from New York.