May 7- Whole Foods Market Inc said on Tuesday store sales have rebounded as it expands efforts to lower prices and reach beyond its core of upscale shoppers by adding more locations, and its shares rose more than 8 percent after hours.
*Ratifies agreement with UFCW 455. *Co's associates working at Kroger Stores in Houston area have ratified new. *Says three-year agreement covers more than 13,729 associates working in 109 stores in the Houston area.