The Muzak bounces between Tejano and country, and the warm tortillas and marinated fajita meat are big sellers at H. E. Butt Grocery (H-E-B). Texas' largest private company and the #1 food retailer in South and Central Texas, H-E-B owns more than 350 supermarkets, including a growing number of large (70,000 sq. ft.) gourmet Central Market stores in major metropolitan areas and 80-plus smaller...