Assessment of gliadin in supposedly gluten-free foods prepared and purchased by celiac patients

Background: The present study was designed to evaluate the presence of glia din in homemade foods prepared by patients with celiac disease and/or their relatives, as well as in processed products consumed by such patients in S ao Paulo, Brazil, by enzyme immunoassay (EIA) and Western blot (WB) analysi s. Methods: One hundred ninety samples were analyzed: 108 homemade foods prepa red in homes of patients with celiac disease, 81 processed products, and 1 positive control of homemade food. All samples were analyzed by EIA based o n monoclonal antibodies to heat stable omega -gliadins and related prolamin s from wheat. rye, and barley. Samples were also analyzed using the WE tech nique. Results: Only one (0.9%) of 108 homemade foods contained detectable amounts of gliadin, as determined by EIA. Twelve of 81 processed products containe d gliadin by EIA, as follows: 5 of 61 without gluten listed in the ingredie nts, 2 of 11 malt extracts, 1 of 2 wheat starches, 1 of 2 types of beer. an d all 3 positive control products. Gliadin content of these products was be tween 4 and 10 mg of gliadin/100 g of product, except for the wheat starch sample (28 mg of gliadin/100 g) and all 3 samples with gluten (>4000 mg of gliadin/100 g). The positive control of homemade food contained 152 mg of g liadin/100 g. One hundred three of 190 samples were analyzed by WE, and 21 of these were gliadin positive. A comparison of results obtained by EIA and WE showed no statistical differences between the methods. Conclusions: The greater part of the foods prepared in homes of patients wi th celiac disease and most processed products supposed to be gluten-frer di d not contain gliadin. Therefore, celiac patients adequately prepare gluten -free homemade food and have the expertise to purchase processed gluten-fre e food in Sao Paulo, Brazil.