Quantitative Detection of Hazelnut (Corylus avellana) in Cookies: ELISA versus Real-Time PCR

Abstract

Hazelnuts (Corylus avellana) are used widely in the food industry, especially in confectionery, where they are used raw, roasted, or in a processed formulation (e.g., praline paste and hazelnut oil). Hazelnuts contain multiple allergenic proteins, which can induce an allergic reaction associated with symptoms ranging from mild irritation to life-threatening anaphylactic shock. To date, immunochemical (e.g., ELISA or dipstick) and PCR-based analyses are the only methods available that can be applied as routine tests. The aim of this study is to make a comparative evaluation of the effectiveness of ELISA and real-time PCR in detecting and correctly quantifying hazelnut in food model systems. To this end, the performances of two commercial ELISAs were compared to those of two commercial and one in-house-developed real-time PCR assays. The results showed that although ELISA seemed to be more sensitive compared to real-time PCR, both detection techniques suffered from matrix effects and lacked robustness with regard to food processing. As these impacts were highly variable among the different evaluated assays (both ELISA and real-time PCR), no firm conclusion can be made as to which technique is suited best to detect hazelnut in (processed) food products. In this regard, the current lack of appropriate DNA calibrators to quantify an allergenic ingredient by means of real-time PCR is highlighted.

Hazelnut Allergens: Molecular Characterization, Detection, and Clinical Relevance

“…matrix effects) and by the effect of food processing (e.g. heat treatments, formation of Maillard products, fermentation, partial hydrolysis) Cucu et al, 2013;Garber and Perry, 2010;Pele et al, 2007;Platteau et al, 2011a;Platteau et al, 2012;Roder et al, 2009). To address the referred issues, some studies have been conducted aiming at evaluating the performance of commercial kits from different brands to detect hazelnut traces in processed foods Garber and Perry, 2010).…”

“…Using the classical SYBR Green I or the enhancement of SYBR GreenER, several real-time PCR systems have been described with high specificity and sensitivity to trace hazelnut allergens in foods (D'Andrea et al, 2009;D'Andrea et al, 2011;Iniesto et al, 2013;Pafundo et al, 2010). As alternative and for the unequivocal identification of hazelnut in complex food matrices, other studies have demonstrated the use of specific hydrolysis probes to enhance the specificity of the reaction (Arlorio et al, 2007;Costa at al., 2012b;Costa et al, submitted;Köppel et al, 2010;Köppel et al, 2012;Piknová et al, 2008;Platteau et al, 2011a;Platteau et al, 2011b), based on the complementarity of a third hybridisation oligonucleotide during the amplification.…”

Setting a protocol for hazelnut roasting using sensory and colorimetric analysis: Influence of the roasting temperature on the hazelnut quality Tonda Gentile delle Langhe cv.

“…Thanks to their flavour, hazelnuts are often used in food production, especially in confectionery: they are often found in pastries, chocolate spreads, ice creams, cereal bars, cookies, nougat, etc. (Platteau et al, 2011).…”

“…Hazelnuts are usually processed integrally into food products, although hazelnut oil is also often used for cooking (Platteau et al 2011). Due to the positive changes of its organoleptic properties during the roasting process, hazelnut is generally roasted before using it in sweets, confectionery, chocolate and biscuits (Demir & Cronin 2005).…”

Development of a sandwich ELISA-type system for the detection and quantification of hazelnut in model chocolates

“…For the detection and quantification of hazelnut in foods, several techniques have been developed, either directly targeting the allergen or other marker proteins (Ansari, Stoppacher, & Baumgartner, 2012;Cucu et al, 2010;Garber & Perry, 2010;Platteau, De Loose, De Meulenaer, & Taverniers, 2011a;Trashin, Cucu, Devreese, Adriaens, & De Meulenaer, 2011) or indirectly via DNA analysis (Arlorio, Cereti, Coisson, Travaglia, & Martelli, 2007;Costa, Mafra, Kuchta, & Oliveira, 2012b;D'Andrea et al, 2011;Platteau, De Loose, De Meulenaer, & Taverniers, 2011b;Platteau et al, 2011a). In the field of protein-based methods, the enzymelinked immunosorbent assays (ELISA) are among the most used approaches for allergen detection (Schubert-Ullrich et al, 2009).…”