Immunomagnetic separation combined with polymerase chain reaction for the detection of Staphylococcus aureus in milk

The present study investigated the use of immunomagnetic separation( IMS) capture as an additional concentration step before PCR in the detection and identification of Staphylococcus aureus( S.aureus) from milk.The optimum technological parameters of the IMS system and the coupling time of immunocapture reactions were investigated and evaluated.The capture efficiencies of the immunomagnetic beads were above 80% for S.aureus in PBS at a bacterial concentration of 101~ 104 CFU/m L. S.aureus could be detected in samples that were otherwise negative by IMS-PCR. The IMS-PCR method showed a detection threshold corresponding to 104 CFU/m L in S.aureus-spiked PBS.In the case of S.aureus-spiked milk,the minimum value of detection was 104 CFU/m L after2 h enrichment.