Development and Improvement of Food Allergen Detection Assays

Enzyme-linked immunosorbent assays (ELISAs) have become the method of choice for the detection of residues of allergenic foods that might contaminate other foods.

ELISAs have a major advantage over other allergen assay methods – the detection of protein residues – because allergens are proteins. ELISAs can be targeted to detect specific proteins including allergenic proteins or can be more generally targeted to detect a range of proteins from the allergenic source.

The Food Allergy Research and Resource Program (FARRP) at the University of Nebraska-Lincoln Department of Food Science and Technology believes that the detection of proteins from the source is a suitable approach because the detection of proteins from a particular food very likely indicates that the allergenic proteins are also present.

FARRP has been an international leader in the development of numerous ELISAs over the years and some of these ELISAs are licensed to Neogen Corporation. FARRP continues to focus on the development of new ELISA methods for the detection of buckwheat, cashew, pistachio, walnut, and pecan.

FARRP is also involved in the evaluation and improvement of ELISAs for detection of allergenic food residue after processing such as baking, frying, boiling, etc. Food processing can affect the assay’s ability to detect food allergens due to changes in protein conformation and solubility.

Threshold Studies

How much is too much? Food-allergic consumers attempt to entirely avoid the allergenic foods that provoke their symptoms (a zero threshold approach).

The food industry attempts to clean shared equipment until no allergens remain (also a zero threshold approach). Because of the uncertainties associated with cleaning to that level, advisory labeling (e.g. may contain x) flourishes.

Yet, in clinical challenge settings, doses can be administered to food-allergic individuals without provoking allergic reactions. Thus, safe doses do exist. But, how much is too much? That question remains.

The major research priority for FARRP is to establish the necessary scientific and clinical evidence and approaches needed to establish threshold levels that are safe for the vast majority of food-allergic consumers.

Food Allergen Identification, Characterization & Stability

Identification of the proteins in foods that cause sensitization in susceptible individuals and the elicitation of allergic reactions in those individuals who are sensitized continues to be a main focus of research. Much of this research has focused on allergens in commonly allergenic foods such as peanuts, soybeans, almonds, hazelnuts, Brazil nuts, and fish; and in less commonly allergenic foods such as lupine, sunflower seeds, sesame seeds, and kiwi.

The stability of allergens to food processing unit operations and to digestion (proteolytic stability) are key characteristics of many food allergens which help to preserve the protein structure and maintain allergenicity.

FARRP is conducting research to examine whether sufficiently intact proteins or immunologically active peptides derived from allergenic food proteins resist gastrointestinal digestion and are absorbed by gut epithelial cells or M cells and interact with the mucosal immune system for extended periods of time which may result in allergic sensitization.

FARRP is also conducting research to determine how different food processing methods affect the allergenicity of the various food proteins.