A biological soil detector and a method for detecting bio soil are provided. The biological soil detector has a solid support member; a specific indicator immobilized on the solid support member, the specific indicator having a material sensitive to the presence of blood; and the solid support and specific indicator positioned within or on a retaining member to readily contact a liquid that has been used to contact a surface. In the method for detecting bio soil, the method includes 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 of the detector described herein; and inspecting the solid support member for a detectable response to determine whether the specific indicator has interacted with biological soil.