Abstract: A closure containing an internalized microbial filter for use in enteral delivery set assemblies. The closure comprises a generally cylindrical side wall, a planar top surface having first and second projections, the first projection being associated with the spikable membrane while the second projection is associated with a filter and with means to limit air access to the filter. The closure also includes a bottom surface having an aperture which extends through the closure to the top surface thereof with the filter being secured to the bottom surface and extending across the opening of the aperture.