Short communicationDevelopment of an immunomagnetic separation method for efficient enrichment of Escherichia coli O157:H7

•The MAbs 10C5-H3-B6 which has high specificity and affinity against E. coli O157:H7 was prepared.•The IMBs exhibited high specific binding with E. coli O157:H7 strains.•The CE of IMBs against E. coli O157:H7 in ground beef and milk were 94.4% and 99.8%.•The IMBs can be used in food safety field.

Immunomagnetic separation uses antibody-coated paramagnetic particles to selectively bind and purify the target organisms from a comprehensive range of complex food matrices. Aim of this study was to develop and optimize an immunomagnetic separation method based on monoclonal antibody for efficient isolation of Escherichia coli O157:H7 in food samples. The key parameters for preparing the immunomagnetic beads; the coupling rate between monoclonal antibody and magnetic beads, additive amount of immunomagnetic beads, and magnetic separation times were optimized with different concentrations of E. coli O157:H7. Under optimized conditions, the capture efficiency (CE) was greater than 98% against 101-106 cells of E. coli O157:H7 with 0.05 mg immunomagnetic beads. The immunomagnetic beads exhibited high specific binding with E. coli O157:H7 strains (CE > 98%), and low binding with non-target bacteria (CE < 2%) except for S. aureus (CE = 23.6%). The capture efficiency of immunomagnetic beads against E. coli O157:H7 in ground beef and milk samples were 94.4% and 99.8%, respectively.