Eric Bogosian fills in for Leonard Lopate. On today’s show: Tracie McMillan discusses what she learned about the American food system by going undercover on a farm, at a Wal-Mart, and a Brooklyn Applebee’s. Writer and editor Craig Taylor discusses his book about life in London. A History of the World in 100 Objects looks at a stone head of the Roman Emperor Augustus. Ruben Santiago-Hudson talks about directing and starring in a new radio play production of Zora Neale Hurston’s “Their Eyes Were Watching God” in WNYC’s Jerome L. Greene Performance Space. And Maggie Anderson talks about the challenges faced by black-owned business.