title: Magnetic nano-beads based separation combined with propidium monoazide treatment and multiplex PCR assay for simultaneous detection of viable Salmonella Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes in food products.
abstract: We developed a rapid and reliable technique for simultaneous detection of Salmonella Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes that can be used in food products. Magnetic nano-beads (MNBs) based immunomagnetic separation (IMS) was used to separate the target bacterial cells while multiplex PCR (mPCR) was used to amplify the target genes. To detect only the viable bacteria, propidium monoazide (PMA) was applied to selectively suppress the DNA detection from dead cells. The results showed the detection limit of IMS-PMA-mPCR assay was about 10(2) CFU/ml (1.2 × 10(2) CFU/ml for S. Typhimurium, 4.0 × 10(2) CFU/ml for E. coli O157:H7 and 5.4 × 10(2) CFU/ml for L. monocytogenes) in pure culture and 10(3) CFU/g (5.1 × 10(3) CFU/g for S. Typhimurium, 7.5 × 10(3) CFU/g for E. coli O157:H7 and 8.4 × 10(3) CFU/g for L. monocytogenes) in spiking food products samples (lettuce, tomato and ground beef). This report has demonstrated for the first time, the effective use of rapid and reliable IMS combined with PMA treatment and mPCR assay for simultaneous detection of viable S. Typhimurium, E. coli O157:H7 and L. monocytogenes in spiked food samples. It is anticipated that the present approach will be applicable to simultaneous detection of the three target microorganisms for practical use.
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, 235 Nanjing East Road, Nanchang 330047, PR China.
authors.forename: Youjun
authors.initials: Y
authors.lastname: Yang
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
authors.forename: Hengyi
authors.initials: H
authors.lastname: Xu
authors.forename: Zoraida P
authors.initials: ZP
authors.lastname: Aguilar
authors.forename: Ruijiang
authors.initials: R
authors.lastname: Niu
authors.forename: Yong
authors.initials: Y
authors.lastname: Yuan
authors.forename: Jichang
authors.initials: J
authors.lastname: Sun
authors.forename: Xingyong
authors.initials: X
authors.lastname: You
authors.forename: Weihua
authors.initials: W
authors.lastname: Lai
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Xiong
authors.forename: Cuixiang
authors.initials: C
authors.lastname: Wan
authors.forename: Hua
authors.initials: H
authors.lastname: Wei
mesh_terms: D000818:Animals; D001386:Azides / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D002417:Cattle; D019453:Escherichia coli O157 / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D018545:Lactuca / Q000382:microbiology*; D008089:Listeria monocytogenes / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D018551:Solanum lycopersicum / Q000382:microbiology*; D008460:Meat / Q000382:microbiology*; D050296:Microbial Viability; D060885:Multiplex Polymerase Chain Reaction / Q000295:instrumentation / Q000379:methods*; D011419:Propidium / Q000031:analogs & derivatives / Q000494:pharmacology; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*
chemical_list: D001386:Azides; C533957:propidium monoazide; D011419:Propidium