Survey of Commercial Food Products for Detection of Walnut (Juglans regia) by Two Elisa Methods and Real Time PCR

Foods

Pablo Cabrera¹  Isabel González¹  Aina García-García¹  Rosario Martín¹  Teresa García¹  Raquel Madrid¹ 

[1] Departamento de Nutrición y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain;

关键词: ELISA;    food allergen labeling;    food analysis;    polyclonal antibody;    real time PCR;    ScFv recombinant antibody;   

DOI  :  10.3390/foods10020440

来源: DOAJ

【 摘 要 】

Labeling of food allergens in accordance with legal regulations is important to protect the health of allergic consumers. The requirements for detecting allergens in foods involve adequate specificity and sensitivity to identify very small amounts of the target allergens in complex food matrices and processed foods. In this work, one hundred commercial samples were analyzed for walnut detection using three different methods: a sandwich enzyme-linked immunosorbent assay (ELISA) kit based on polyclonal antibodies, a direct ELISA using a recombinant multimeric scFv, and a real time PCR. The most sensitive method was real time PCR followed by sandwich ELISA kit and multimeric scFv ELISA. There was agreement between the three methods for walnut detection in commercial products, except for some heat-treated samples or those that contained pecan. The walnut ELISA kit was less affected by sample processing than was the multimeric scFv ELISA, but there was cross-reactivity with pecan, producing some false positives that must be confirmed by real time PCR. According to the results obtained, 7.0 to 12.6% of samples (depending on the analytical method) contained walnut but did not declare it, confirming there is a risk for allergic consumers. Moreover, there was one sample (3.7%) labelled as containing walnut but that tested negative for this tree nut. Genetic and immunoenzymatic techniques offer complementary approaches to develop a reliable verification for walnut allergen labeling.

【 授权许可】

Unknown