The invention relates to a Bacillus spore specific antigen. Compositions and methods relating to the antigen are provided along with antibodies against the antigen. The antigen is specific for Bacillus spores relative to the vegetative form of the cells. The antigen is detectable on ungerminated spores. The antibodies may be used to detect the presence of Bacillus spores by use of methods provided herein. The invention also relates to articles of manufacture as well as kits comprising the antibodies which may be used in the detection methods of the invention.