Abstract:Objective: To preparation a Listeria monocytogenes specified phage-display single-chain antibody fragments immuno-magnetic beads (scFv-IMBs), the effectiveness of scFv-IMBs was evaluated by artificial contamination. Method: the capture efficiency and the ability of scFv-IMBs for separating L. monocytogenes from L. innocua in frankfurters was compared to commercially available anti-Listeria immunomagnetic beads (Dyna-IMBs) using qualitative and quantitative culture method, as well as PCR method, in various enrichment systems. Result: the capture efficiency of scFv-IMBs for L. monocytogenes was 15%-55%, which is better than the efficiency of Dyna-IMBs (0.85%-1.27%), and scFv-IMBs shows good specificity. The capture efficiency of those IMBs in MOPS-BLEB could reach 62%-88%, which was better than IMBs in UVM media (<5%) and FB media (<53%). Moreover, the scFv-IMBs displayed higher specificity to L. monocytogenes (P<0.01) even when the initial cells concentration of L. innocua were 1 000 times more than that of L. monocytogenes spiked in commercial frankfurters exudates. And the detection limitation combined with scFv-IMBs could reach 1 CFU/mL. Conclusion: scFv-IMBs have better specificity and separation ability than Dyna-IMBs, which could significantly lower the interference of L. innocua in complex matrix.