Duplex real-time PCR method for the detection of sesame (Sesamum indicum) and flaxseed (Linum usitatissimum) DNA in processed food products

Abstract

The development of a duplex real-time polymerase chain reaction (PCR) method allowing the simultaneous detection of sesame and flaxseed DNA in commercial food products is described. This duplex real-time PCR technique is based in the design of sesame- and flaxseed-specific primers based on the ITS1 region and two TaqMan fluorescent probes. The method was positive for sesame and flaxseed, and showed no cross-reactivity for all other heterologous plant and animal species tested. Sesame and flaxseed could be detected in a series of model samples with defined raw and heat-treated sesame in flaxseed, and flaxseed in sesame, respectively, with detection limits of 1.3 mg kg(-1) for sesame and 1.4 mg kg(-1) for flaxseed. The applicability of the assay for determining sesame and flaxseed in different food matrices was investigated by analysing a total of 238 commercial foodstuffs. This PCR method is useful for highly selective and sensitive detection of traces of sesame and flaxseed in commercial food products.

Sesame, Pistachio, and Macadamia Nut: Development and Validation of New Allergenic Systems for Fast Real-Time PCR Application

“…Sesame (Sesamum indicum L.) belongs to the Pedaliaceae family. Roasted sesame seed could be found in different types of food such as bakery products (snacks, breads, biscuits), processed meat, fast foods, vegetarian food, and ethnic dishes, or it could be consumed in the form of oil used for cooking above all in Oriental, Chinese, and South American cuisines [ 19 , 20 , 21 ]. Sesame has always been considered one of the major causes of food allergy [ 22 , 23 , 24 ], and moreover, it is increasing in some countries such as Israel and France, where the highest prevalence was observed [ 21 ].…”

“…U97700), while Zhang et al, 2018 [ 36 ] studied 2S albumin in SYBR green assay. Furthermore, Lopez-Calleja et al, 2015 [ 20 ] applied PCR systems on an internal transcribed spacer (ITS) region (NCBI acc. No.…”

“…No. AF161883) as the target for TaqMan real-time PCR and LPA systems, respectively; López-Calleja et al, 2015 [ 20 ] and Ito et al, 2018 [ 48 ] applied the ITS multi-copy gene in real-time PCR and TB green (intercalator-based reagent) singleplex/tetraplex PCR, respectively. All the methods exhibited a 100% of specificity, even if Brežná et al, 2009 [ 47 ] tested an exclusivity panel of 16 plant species and without including the pecan nut.…”

“…All the methods exhibited a 100% of specificity, even if Brežná et al, 2009 [ 47 ] tested an exclusivity panel of 16 plant species and without including the pecan nut. LOD values obtained in the different studies ranged from 1.45 pg (practical LOD: 0.02%) [ 47 ] to 0.1 mg/kg [ 20 ] and to 1 pg [ 48 ].…”