title: High resolution TaqMan real-time PCR approach to detect hazelnut DNA encoding for ITS rDNA in foods.
abstract: A broad range of foods have been described as causing allergies, but the majority of allergic reactions can be ascribed to a limited number of food components. Recent extensive surveys showed how tree nuts, particularly hazelnut (Corylus avellana L.) seeds, rank amongst the most important sources of food allergy. In order to protect the allergic consumer, efficient and reliable methods are required for the detection of allergenic ingredients. For this purpose, we have developed a real-time polymerase chain reaction (PCR) for detection of hazelnut in commercial food products. In this way a specific hazelnut primer pair based on the ITS marker (70 bp) and a nuclease (TaqMan) probe labelled with FAM and BHQ were designed. Sensibility of real-time PCR was determined by analysis of raw and heat treated hazelnut-wheat flour mixtures with a range of detection of 0.1-100,000 ppm. Practical applicability of the real-time PCR assay developed for determining hazelnut in different food matrices was investigated by analyzing 179 commercial foodstuffs comprising snacks, biscuits, chocolates, bonbons, creams, nut bars, ice creams, precooked meals, breads, beverages, yogurts, cereals, meat products, rice cake and nougat. From the total of samples analyzed, 40 commercial food products that didn't declare hazelnut nor traces on the label were found to contain hazelnut. The real-time PCR method proposed herein due to its high sensitivity facilitates the detection of hazelnut traces in commercial food products and can also be useful for monitoring the effectiveness of cleaning processes and as consequence, can help to prevent the food allergic consumer from unintentional ingestion of hidden allergens.
authors.affiliation: Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain. ilopezcalleja@vet.ucm.es
authors.forename: Inés María
authors.initials: IM
authors.lastname: López-Calleja
authors.forename: Silvia
authors.initials: S
authors.lastname: de la Cruz
authors.forename: Nicolette
authors.initials: N
authors.lastname: Pegels
authors.forename: Isabel
authors.initials: I
authors.lastname: González
authors.forename: Teresa
authors.initials: T
authors.lastname: García
authors.forename: Rosario
authors.initials: R
authors.lastname: Martín
mesh_terms: D031211:Corylus / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics*; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D005504:Food Analysis; D005506:Food Contamination / Q000032:analysis*; D060888:Real-Time Polymerase Chain Reaction / Q000295:instrumentation / Q000379:methods*; D019914:Taq Polymerase / Q000737:chemistry
chemical_list: D018744:DNA, Plant; D021903:DNA, Ribosomal Spacer; D019914:Taq Polymerase
keywords: Commercial food products; Food authenticity; Hazelnut (Corylus avellana L.); TaqMan real-time PCR; Traceability