title: Rapid detection of Staphylococcus aureus in dairy and meat foods by combination of capture with silica-coated magnetic nanoparticles and thermophilic helicase-dependent isothermal amplification.
abstract: Staphylococcus aureus is one of the main pathogens in dairy and meat products; therefore, developing a highly sensitive and rapid method for its detection is necessary. In this study, a quantitative detection method for Staph. aureus was developed using silica-coated magnetic nanoparticles and thermophilic helicase-dependent isothermal amplification. First, genomic DNA was extracted from lysed bacteria using silica-coated magnetic nanoparticles and amplified using thermophilic helicase-dependent isothermal amplification. After adding the nucleic-acid dye SYBR Green I to the amplicons, the fluorescence intensity was observed using a UV lamp or recorded using a fluorescence spectrophotometer. This detection system had a detection limit of 5×10(0) cfu/mL in pure culture and milk-powder samples and 5×10(1) cfu/mL in pork samples using a UV light in less than 2h. In addition, a good linear relationship was obtained between fluorescence intensity and bacterial concentrations ranging from 10(2) to 10(4) cfu/mL under optimal conditions. Furthermore, the results from contaminated milk powder and pork samples suggested that the detection system could be used for the quantitative analysis of Staph. aureus and applied potentially to the food industry for the detection of this pathogen.
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.
authors.forename: Xingxing
authors.initials: X
authors.lastname: Chen
authors.affiliation: School of Basic Medical Science, Jiangxi University of Chinese Traditional Medicine, Nanchang, Jiangxi, 330000, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.
authors.forename: Min
authors.initials: M
authors.lastname: Gan
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.
authors.forename: Lihua
authors.initials: L
authors.lastname: He
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.
authors.forename: Hengyi
authors.initials: H
authors.lastname: Xu
authors.affiliation: Food and Nutritional Science, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong. Electronic address: npshah@hku.hk.
authors.forename: Nagendra P
authors.initials: NP
authors.lastname: Shah
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China. Electronic address: weihua114@live.cn.
authors.forename: Hua
authors.initials: H
authors.lastname: Wei
mesh_terms: D000818:Animals; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D004269:DNA, Bacterial / Q000302:isolation & purification*; D003611:Dairy Products / Q000032:analysis / Q000382:microbiology*; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D008460:Meat / Q000032:analysis / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D013552:Swine
chemical_list: D020099:Coated Materials, Biocompatible; D004269:DNA, Bacterial; D058185:Magnetite Nanoparticles; D012822:Silicon Dioxide
keywords: SYBR Green I; Staphylococcus aureus; silica-coated magnetic nanoparticles; thermophilic helicase-dependent isothermal amplification