Short communication: A novel method using immunomagnetic separation with a fluorescent nanobeads lateral flow assay for the rapid detection of low-concentration Escherichia coli O157:H7 in raw milk

Escherichia coli O157:H7 is an important serotype of enterohemorrhagic E. coli that was first identified as a human pathogen in 1982. This pathogen causes several serious diseases. In this study, immunomagnetic separation was coupled with a fluorescent nanobeads lateral flow assay to establish a sensitive and rapid detection method for Escherichia coli O157:H7 in raw milk. The pathogen was captured from raw milk by immunomagnetic separation with immunomagnetic nanobeads and then detected using a fluorescent nanobeads lateral flow assay. A fluorescent line was formed in the test line of the test strip and quantitatively detected using a fluorescent reader. Screening times, which included immunomagnetic separation and the fluorescent nanobeads lateral flow assay, were 8, 7, 6, and 5 h when 1, 5, 25, and 125 cfu of E. coli O157:H7, respectively, were inoculated into 25 mL of raw milk. The established method could be widely applied to the rapid onsite detection of other pathogens to ensure food safety.