A method of separating a liquid from a liquid-laden solid material includes providing a trough having a deck defining a support surface with passages extending through the support surface. The changeable stripe may be applied directly and integrally into the structure of the shoe component, or it may be held by an independent base structure and applied by stitching or adhesive to the shoe. The underfill recognition system determines whether the test sensor initially is substantially full-filled or underfilled, indicates when the sample volume is underfilled so that additional sample may be added to the test sensor, and starts or stops the sample analysis in response to the sample volume.