"Trust in every bite", is the slogan for Yum Brands Inc's (YUM. N) KFC website in China.

This message is a part of the company's new campaign "I Commit" which is intended to restore confidence among the customers in its largest market. Many of the customers stopped this food chain stores after the Chinese media reported about excessive antibiotic use by a few KFC suppliers a year ago.

In November a survey found that nearly 40 percent of the respondents were extremely concerned about the use of antibiotics in KFC chickens.  

Yum initially predicted that safety fears would quickly fade away after the television report on antibiotics. But the sales figures speak otherwise. As the rate of sales are yet to turn around, and it has pushed back the recovery timeline.

Chinese consumers when interviewed suggest that rather than soothing concerns, the advertisement remind the diners about the food safety scare at the fried chicken chain, which could challenge Yum's mission to revive sales. There's a lot at risk for Yum. It is China's largest Western restaurant operator with approximately 4,500 KFC outlets and the company reaps more than half of its overall operating profit there.