Detection of Escherichia coli O157:H7 and Salmonella in ground beef by a bead-free quantum dot-facilitated isolation method

► We developed novel quantum dot (QD)-labeled antibody reporters for E. coli O157:H7 and Salmonella. ► The developed crosslinked QD-antibody conjugates were strong and cost efficient. ► The bead-free cell isolation method employed improved the limit of detection. ► When applied to ground beef, levels as low as 10 CFU of pathogens per gram of artificially inoculated ground beef could be detected after a 24-h enrichment.