Gluten-free beer example: Sheehan, Evans & Skerritt, 2001). Brewers who produce low gluten beers are required to test every batch for gluten, and record gluten levels in "parts per million" ('ppm'). Although the barley hordein in such tests may not be detected, smaller pieces of these proteins, known as peptides, may remain and be toxic for celiacs. Those involved in gluten-free brewing, and others representing celiacs or those with other conditions that require a gluten-free diet, tend to be concerned that beer brewed using wheat or barley are not appropriate for those with celiacs or dermatitis herpetiformis, although the carefully controlled gluten
Anti-gliadin antibodies in food products. Some of these antibodies can recognize only wheat prolamins or very closely related grass seeds; others can detect antigens over broad taxa. The G12 antibody is the newest example which detects the most immunotoxic fragment, a 33-mer peptide from �-2 gliadin; available from Romer Laboratories and the Spanish company Biomedal. It recognizes the toxic fraction of wheat, barley, rye and also of oat. The R5 sandwich assay is another such assay. This assay can recognize wheat, barley and rye, which makes it ideal for evaluating the presence of contaminants in gluten-free foods that do not contain oat.