Why we are incubating membrane filter plates incubating upright position why not inverted?

Why we are incubating membrane filter plates incubating upright position why not inverted ???.

Simple they may be incubated membrane filter having plate its easily to remove filter from the media because they filter loss of the own moisture.

Is it recommend in any guidelines to incubate plate in upright position bcoz we keep inverted only.

The basically analyzed plate is should be incubated in inverted position only because they have some reasons are available. But if you have used membrane filtration method the placed membrane may be dropped in a top of plate chances also highly possible in inverted position. So that only reason are mostly place the plate are incubated upright position there no mentioned in USP and IP and other regulatory bodies.