Culinary historian Michael Twitty traces his ancestry through food in "The Cooking Gene: A Journey Through African-American Culinary History in the Old South." The memoir won the 2018 James Beard Foundation's Award for Book of the Year. In it, Twitty explores the complex question of who owns Southern food. GPB's Tony Harris spoke with Twitty about why he wanted to wrestle with that question and his passion for food justice.