Rapid enrichment and detection of Staphylococcus aureus in milk using polyethyleneimine functionalized magnetic nanoparticles

Staphylococcus aureus (S. aureus) is a common foodborne pathogen, which could cause serious bacteremia and infective endocarditis. Establishing a rapid and low-cost method to capture and detect S. aureus in food samples is necessary. In this study, we have developed a method on the basis of polyethyleneimine-functionalized magnetic nanoparticles (MNP-PEI) and recombinase aided amplification (RAA) for rapid enrichment and analysis of S. aureus in milk. The capture efficiency of MNP-PEI on multiple strains of bacteria and influencing factors were studied. The limits of detection (LOD) of the MNP-PEI-RAA strategy were 2.9 x 10(1) CFU.mL(-1) in phosphatebuffered saline (PBS) and 2.9 x 10(2) CFU.mL(-1) in milk. The entire enrichment and detection processes could be completed within 60 min. The detection strategy based on MNP-PEI and RAA had low cost, short detection time, and high sensitivity. In addition, the broad-spectrum of bacteria captured by MNP-PEI was important for simultaneous analysis of a variety of bacteria, which provided an effective tool for evaluating the microbiological safety of food samples.