title: Rapid detection of norovirus from fresh lettuce using immunomagnetic separation and a quantum dots assay.
abstract: Current molecular methods that include PCR have been used to detect norovirus in many food samples. However, the protocols require removing PCR inhibitors and incorporate time-consuming concentration steps to separate virus from analyte for rapid and sensitive detection of norovirus. We developed an immunomagnetic separation (IMS) and a quantum dots (QDs) assay to detect norovirus eluted from fresh lettuce with Tris buffer containing 1% beef extract (pH 9.5). IMS facilitated viral precipitation with a 10-min incubation, whereas virus concentration using polyethylene glycol (PEG) requires more than 3 h and an additional high-speed centrifugation step to precipitate virus before reverse transcription PCR (RT-PCR) analysis. The fluorescence intensity of QDs was detected qualitatively on norovirus dilutions of 10(-1) to 10(-3) in a stool suspension (100 RT-PCR units/ml). The results suggest that a fluorescence assay based on IMS and QDs is valid for detecting norovirus qualitatively according to fluorescent signal intensity within the same virus detection limit produced by IMS-RT-PCR and PEG-RT-PCR.
authors.affiliation: Department of Food Science and Technology and Functional Food Research Center, Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: Hee-Min
authors.initials: HM
authors.lastname: Lee
authors.forename: Joseph
authors.initials: J
authors.lastname: Kwon
authors.forename: Jong-Soon
authors.initials: JS
authors.lastname: Choi
authors.forename: Kyeong-Hwan
authors.initials: KH
authors.lastname: Lee
authors.forename: Sung
authors.initials: S
authors.lastname: Yang
authors.forename: Sang-Mu
authors.initials: SM
authors.lastname: Ko
authors.forename: Jae-Keun
authors.initials: JK
authors.lastname: Chung
authors.forename: Se-Young
authors.initials: SY
authors.lastname: Cho
authors.forename: Duwoon
authors.initials: D
authors.lastname: Kim
mesh_terms: D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods*; D018545:Lactuca / Q000821:virology*; D029322:Norovirus / Q000302:isolation & purification*; D045663:Quantum Dots; D012680:Sensitivity and Specificity; D013997:Time Factors