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.

Abstract

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 5h when 1, 5, 25, and 125 cfu of E. coli O157:H7, respectively, were inoculated into 25mL of raw milk. The established method could be widely applied to the rapid onsite detection of other pathogens to ensure food safety.