I work at Winn-Dixie and have a friend that works at corporate (southeastern grocers; winn dixie is one of their subsidiary store lines).
This bankruptcy filing is merely a preventative measure to help centralize the company and get rid of stores that are costing more to operate than what they make. In other words, this is a filing to reduce attrition.
It's not much to be concerned about. No wages are being cut at my store thus far.