Enzyme immunoassay for determination of gluten in foods: collaborative study.
A collaborative study was performed in 15 laboratories to validate a monoclonal antibody-based enzyme immunoassay (EIA) for determination of gluten in foods. The study included 13 samples: maize starch, "gluten-free" baking mixes, wheat flours, cookies, cooked meats, and a soup. Gluten was present in these samples at either zero or 0.02 to 10% by weight, i.e., over almost 3 orders of magnitude. The mean assay values for the foods varied from 88 to 105% of the actual amounts. The assay was quantitative for cereal products and the soup with repeatability (RDS-r, relative standard deviation) and reproducibility (RSD-R) of 16-22% and 24-33%, respectively. The assay was semiquantitative for the processed meat products (RSD-r 14 and 26% and RSD-R 46 and 56%), probably because gluten was unevenly distributed in the small (1 g) samples that were analyzed. The ELISA method produced no false positive results, and false negatives obtained with tannin-containing foods could be avoided by use of a modified sample extractant. None of the collaborators reported problems in following the protocol. The method has been adopted official first action by AOAC for determination of wheat gluten in foods.
Skerritt
J H
JH
CSIRO Wheat Research Unit, North Ryde, New South Wales, Australia.
Hill
A S
AS
D000911:Antibodies, Monoclonal; D004797:Enzyme-Linked Immunosorbent Assay; D005504:Food Analysis / Q000379:methods*; D005983:Glutens / Q000032:analysis*; D007202:Indicators and Reagents; D011933:Reagent Kits, Diagnostic; D012015:Reference Standards; D015203:Reproducibility of Results
D000911:Antibodies, Monoclonal; D007202:Indicators and Reagents; D011933:Reagent Kits, Diagnostic; D005983:Glutens