Bread crust samples were cut in circular shapes (⍉10 mm) and carefully deposited onto carbon tabs (Agar Scientific, Stansted, UK),coated with carbon (Agar turbo carbon coater) and placed on the stage of a FEI Quanta 3D 200 dual beam Focused Ion Beam Scanning Electron Microscope (FIM-SEM, FEI, Hillsboro, USA). Images were
acquired using secondary electron imaging at an accelerating voltage of 5e15 kV.