A biological soil detector is provided, the detector including: a solid support member; a specific indicator immobilized on the solid support member; and the solid support member and specific indicator positioned to contact liquid that has been used to contact a surface. The invention also provides a method for detecting biological soil on a surface, the method including the following steps: contacting the surface with a liquid; after the liquid has contacted the surface, contacting the liquid with the solid support member and the specific indicator; and inspecting the solid support member to determine whether the specific indicator has interacted with biological soil.