Specific and sensitive ELISA for measurement of IgE-binding variations of milk allergen β-lactoglobulin in processed foods.

Immunochemical detection of food allergens is usually based on the use of polyclonal or monoclonal immunoglobulins G (IgG) antibodies. However, due to differences in epitopes recognition between IgG and IgE, an epitope modification during food processing can potentially alter allergenicity and detection in such different way. For that reason, the use of traditional immunological methods to anticipate or study the protein allergenicity is not recommended. The objective of this work was to develop a standardized competitive ELISA, based on recombinant IgE antibodies to β-lactoglobulin (β-lg), to reveal and to measure changes in β-lg immunoreactivity provoked by technological processes in foods containing this milk protein. As a result, a sensitive immunochemical method (Limit of Detection, LOD < 0.2 μg mL-1) has been developed for β-lg recognition. Also, this technique has been confirmed to detect modifications in β-lg-IgE binding after food processing (thermal treatment) in a similar way to those results obtained with allergic patients in previous works. Consequently, data obtained with this assay could be used as a preliminary test to predict in vitro β-lg allergenic behavior in allergenicity studies in processed foods.