Changes in the Detection Level of Enzyme-Linked Immunosorbent Assay for Food Allergens due to Heating or Irradiation

Abstract

Some proteins that cause food allergies may denature and alter their antigenicity when subjected to heat or other treatments. In this study, we treated egg white and milk using either heating or irradiation (9 or 30 kGy of gamma rays or electron beams). We investigated the changes in the detection level of enzyme-linked immunosorbent assay (ELISA) for these proteins. The proteins were extracted using either Tris-HCl buffer or a denaturing buffer that contains a surfactant and a reducing agent. The detection level of ELISA for ovalbumin (OVA) from egg white, and casein and β-lactoglobulin (β-LB) from milk, were assessed. The results indicated that the OVA levels in the Tris-HCl buffer extract of the heat-treated egg white were about 10^-2 to 10^-3 of the control sample. Also the OVA levels of the irradiated egg white declined. The casein levels in milk with high-dose irradiation declined. The decreases of β-LB levels were not as pronounced with irradiation as with the heat treatment.