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Chapter 8 : Approaches to the Detection of Food Allergens, from a Food Science Perspective
Category: Immunology; Applied and Industrial Microbiology
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Food allergies have become an increasingly important food safety issue in recent years. The current approaches for the prevention of future reactions are focused on the evaluation of the inadvertent presence of allergenic material in food and the identification of the allergen on labels by the consumer governed by the implementation of new regulations in several countries. Depending on the type of target molecule, protein, or DNA, the current detection methods for food allergens can be classified as immunoassay or polymerase chain reaction (PCR). Immunoassay is a very versatile technique because it uses antibodies that have the ability to detect a very specific protein(s) (allergen[s]) within a complex mixture of compounds. On the other hand, PCR targets the gene encoding the protein or allergen of interest. This chapter provides an overview of the current trends for the detection of food allergens, based on published information and the factors and steps involved in the analysis process. Moreover, special attention will be focused on commercially available kits. A section discusses the future approaches, such as the applicability of proteomics and genomics in the field, automation of analysis procedures, and confirmatory methods. From the point of view of detection of food allergens by immunoassay, allergenic proteins are comparable to nonallergenic proteins in that they are both antigens that are detected by IgG antibodies. As technology advances, new analytical techniques are being applied to the field of detection of food allergens or the characterization of new ones.
Key Concept Ranking
ELISA formats: sandwich (A), sandwich enhanced (B), and competitive (C).
Scheme of a lateral flow test.
Peanut protein extracted from light and dark roasted peanut flour with phosphate buffer (pH 7.4) (PBS), high-salt buffer (pH 7.4) (HSB), carbonate buffer (pH 9.5) (Carb), and Tris buffer (pH 8.2) (Tris). (Reproduced with permission from the Journal of AOAC International [ Westphal et al. 2004 ].)
Typical standard curve in sandwich ELISA and direct ELISA, used to determine the concentration of an allergen in a blind sample.
Steps of a conventional PCR cycle.
Mandatory or recommended labeling of allergenic ingredients
Published ELISA protocols for the detection of allergenic foods a
Commercial kits for the detection of food allergens a
Nomenclature of allergenic proteins a
Characteristics of commercial kits for the detection of egg or egg proteins a
Published PCR and RT-PCR protocols for the detection of allergenic foods a