Abstract: A method of determining the presence or absence of a target microorganism in a sample to be tested, the method comprising: (a) combining with the sample an amount of bacteriophage capable of attaching to the target microorganism to create a bacteriophage-exposed sample; (b) providing conditions to the bacteriophage-exposed sample sufficient to allow the bacteriophage to attach to the target microorganism while inhibiting phage replication in a potentially cross-reactive, non-target microorganism; and (c) assaying the bacteriophage-exposed sample to detect the presence or absence of a bacteriophage marker to determine the presence or absence of the target microorganism; wherein the amount of the bacteriophage is between 10% to 70% of the threshold number of bacteriophage that the assay can detect, or between 1×106 pfu/mL and 7×106 pfu/mL.

Abstract: A method for detecting one or more target bacteria in a raw sample where: 1) bacteriophage(s) specific to each target bacterium are added to the raw sample, 2) the test sample is incubated, and 3) the test sample is tested for the presence of each phage in sufficient numbers to indicate the presence of the associated target bacteria in the raw sample. In one embodiment, each phage is initially added to the raw sample in concentrations below the detection limit of the final phage detection process. In another embodiment, the parent phages are tagged in such a way that they can be separated from the progeny phage prior to the detection process. Preferred phage detection processes are immunoassay methods utilizing antibodies that bind specifically to each phage. Antibodies can be used that bind to the protein capsid of the phage. Alternatively, the phage can by dissociated after the incubation process and the sample tested for the presence of individual capsid proteins or phage nucleic acids.

Abstract: A sample to be tested for the presence of a target microorganism is exposed to bacteriophage and conditions are provided to inhibit phage attachment to or replication in a potentially cross-reactive, non-target microorganism. The sample is incubated and assayed to detect the presence or absence of a bacteriophage marker to determine the presence or absence of the target microorganism. The inhibiting may comprise the addition of an inhibiting substance or the use of an inhibiting process. It may include inhibiting the growth of potentially cross-reactive bacteria while allowing growth of the target bacteria, selectively removing or blocking potential cross-reactive bacteria using selective binding agents or selectively destroying potentially cross-reactive bacteria.