Joliet-based Central Grocers filed for Chapter 11 bankruptcy protection on Thursday and as a result plans to lay off over 500 employees at their Joliet warehouse. Central Grocers has been in business for over 100 years as a wholesale grocery cooperative that works with stores throughout the Chicagoland area. Layoffs are planned to take place between June 26 and July 10. The company will also continue with its planned sell of 22 Strack & Van Til stores and as well as closing nine Ultra Food stores. The company intends to auction off the almost 1 million-square-foot Joliet warehouse and headquarters.