Screening and Optimization of Conditions for Untargeted Enrichment of Foodborne Pathogens by Amino Magnetic Beads
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
In this study, a method for the simultaneous enrichment of Salmonella typhimurium, Staphylococcus aureus and Listeria monocytogenes was developed based on the electrostatic enrichment technology using amino magnetic beads. Three different sized amino magnetic beads (5~200 μg; 1 μm, 300 nm, 100 nm) were added respectively into each bacterial solution (2 mL; 103 CFU/mL), and the enrichment efficiency of each bacteria was detected after the incubation was conducted for 5~90 min. The results of the orthogonal enrichment tests for the single bacteria system were applied to the single factor tests and orthogonal tests of the mixed bacteria system, and the final results were applied to the large-volume experimental system and actual samples (commercially available milk and fruit salad). The results showed that when the addition amount of amino magnetic beads was 50 μg and the incubation time was 30 min, the capture rate for the three kinds of pathogens could reach over 60%. All reactions were performed in PBS at pH 7.4. The bead diameter was selected to be 300 nm (p<0.05). The capture rate was higher than 55% when the minimum concentration of the three mixed bacteria was 2×102 CFU/g (mL) in the actual samples of milk and fruit salad. This result could reach the detection limit of fluorescence quantitative PCR. Compared with immunomagnetic beads, the amino magnetic beads had many advantages, such as high stability over storage, low cost and high efficiency. The ability of untargeted enrichment provides an effective pretreatment enrichment method for the rapid detection of downstream foodborne pathogens.
