A supermarket chain is banning unaccompanied minors inside select stores after 6 p.m. and large bags in Washington, D.C., and Maryland as part of a new policy aimed at curbing rampant retail theft.

Grocery chain Giant Food is getting a handle on bags, inspecting them upon exit at certain D.C.-area stores. This comes after large bags and suitcases were banned from entering Giant in May in an ...