This test method may be applied to determine the suitability of grid-marked membrane filters for use in bacteriological culture techniques for the detection and enumeration of bacterial organisms.

A particularly sensitive organism and growth conditions have been selected for this test method in order to maximize sensitivity to toxic materials possibly present in the inks used for grid-marking membrane filters.

1.1 This test method describes a procedure whereby the user of ink-gridded membrane filters in water quality studies can ascertain whether or not the grid lines are toxic and inhibitory to bacterial growth when the membrane and its entrapped bacteria are incubated on a suitable media.

1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use .