title: Specific detection and quantification of Aspergillus flavus and Aspergillus parasiticus in wheat flour by SYBR® Green quantitative PCR.
abstract: Aflatoxins are important mycotoxins that represent a serious risk for human and animal health. These mycotoxins are mainly produced by Aspergillus flavus and Aspergillus parasiticus, two closely related species with different array of aflatoxins. In this work, two specific quantitative PCR (qPCR) assays were developed to detect and quantify both species in wheat flour using primers based on the multicopy ITS2 rDNA target sequence. The species specificity of the assays was tested in a wide range of strains of these species and others colonizing the same commodities. The sensitivity of the assay was estimated in 2.5 pg/reaction in both species. Discrimination capacity for detection and relative quantification of A. flavus and A. parasiticus DNA were analyzed using samples with DNA mixtures containing also other fungal species at different ratios. Both qPCR assays could detect spore concentrations equal or higher than 10(6)spores/g in flour samples without prior incubation. These assays are valuable tools to improve diagnosis at an early stage and in all critical control points of food chain integrated in HACCP strategies.
authors.affiliation: Dpto. Microbiología III, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Noelia
authors.initials: N
authors.lastname: Sardiñas
authors.forename: Covadonga
authors.initials: C
authors.lastname: Vázquez
authors.forename: Jéssica
authors.initials: J
authors.lastname: Gil-Serna
authors.forename: Ma Teresa
authors.initials: MT
authors.lastname: González-Jaén
authors.forename: Belén
authors.initials: B
authors.lastname: Patiño
mesh_terms: D001230:Aspergillus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D001231:Aspergillus flavus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004271:DNA, Fungal / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D005433:Flour / Q000382:microbiology*; D005516:Food Microbiology; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013045:Species Specificity; D013172:Spores, Fungal / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D014908:Triticum / Q000382:microbiology
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer