Allergen immunoassays—considerations for use of naturally incurred standards

Abstract

The enzyme-linked immunosorbent assay (ELISA) offers many advantages for the detection of potentially hazardous allergenic food residues that might become adventitious components of other foods during the course of food production and processing. ELISAs detect proteins, and food allergens are proteins. ELISAs are sufficiently sensitive and specific for detection of food allergen residues. ELISAs can also be produced in formats that are compatible with the industrial food processing environment. However, ELISAs also have disadvantages that should be carefully evaluated and widely recognized. Various food-processing operations can have profound effects on the detectability of allergenic food residues. ELISAs detect intact proteins but protein hydrolysates evade detection in some ELISA formats. The residual proteins present in some ingredients derived from commonly allergenic sources may also not be easily detected with ELISAs because of the nature of the protein residues remaining, e.g. lipophilic. Processing operations can dramatically lower the solubility of proteins. In some food formulations, heat processing, in particular, induces chemical modifications that can affect antibody binding to epitopes in the ELISA. The use of naturally incurred standards where allergenic food residues are incorporated into various representative food matrices and then processed in a manner similar to "real-world" food processing can reveal some of the limitations of allergen ELISAs. Methods for the preparation of naturally incurred standards in chocolate, cookie, muffin, ice cream, pasta, frankfurter, and cream of potato soup are provided as examples.

Detection of the peanut allergen Ara h 6 in foodstuffs using a voltammetric biosensing approach

“…For calibration purposes, Ara h 6 standard solutions with increasing concentrations (1,5,10,50, and 100 ng/ml) were prepared and analyzed with the immunosensor. A linear semilogarithmic relationship between Ara h 6 concentration ([C]) and the i p was obtained between 1 and 100 ng/ml:…”

“…Three main groups of methods for allergens detection are described in the literature, namely, immunoassays for protein detection [9][10][11], DNA-based methods [11,12], and mass spectrometry [13]. Recently, biosensors appeared as great alternatives to classical methods, showing advantages such as a significant reduction of reagent consumption and the possibility of miniaturization and consequent portability [14].…”

Detection of Ara h 1 (a major peanut allergen) in food using an electrochemical gold nanoparticle-coated screen-printed immunosensor

“…In this perspective, reliable, accurate, and highly sensitive and selective methods are needed to evaluate, with assurance, if a certain allergen is (or not) present in a foodstuff. The methodologies available for allergens detection can be divided into three main groups: immunoassays for protein detection (Besler et al, 2002;Monaci and Visconti, 2010;Taylor et al, 2009), DNA-based methods (Słowianek and Majak, 2011;Monaci and Visconti, 2010) and mass spectrometry (Monaci and Visconti, 2009). Biosensors have been emerging recently as powerful alternatives to classical methods for the detection and quantification of allergens, but their application in this field is still scarce.…”

Advances in Authenticity Testing for Meat Speciation

“…Another limitation of ELISA regards the identification of species in processed meat products since proteins can suffer denaturation that leads to specific epitope alterations and consequent decreased sensitivity or even false negatives. Moreover, potential target proteins for ELISA are often irreversibly aggregated, insoluble, and difficult to extract in highly processed products (Taylor et al, 2009;Kotoura et al, 2012). To overcome this drawback, the use of antibodies raised against heat-resistant muscle proteins, such as skeletal muscle protein troponin I, has been proposed in different reports (Chen et al, 1998;Chen and Hsieh, 2000;Djurdjevic et al, 2005;Liu et al, 2006;Zvereva et al, 2015).…”