A sealed container containing a foodstuff or beverage has a lid that includes a heat-sealable, composite film that includes a polymeric substrate layer having a first and second surface, a primer layer that includes PVdC disposed on the first surface, and a heat-sealable polymeric layer extrusion coated on the primer layer. The heat-sealable polymeric layer is 12 μm thick or less and includes a copolymer having repeating monomeric units of ethylene and at least a second type of repeating monomeric unit having the formula [—CH2C(R1)(X)—] wherein: X is selected from —COOR2 and —OC(O)CH3; R1 =H or methyl; and R2 is H, C1-10 alkyl or a counterion M.