Current Detection and Quantification Method for Gluten to Support the Gluten-Free Claim: An Insight about ELISA Method

Celiac disease (CD) is an enteropathy mediated by immunological mechanisms triggered by the interaction of gluten with the intestinal mucosa in affected individuals [1]. The consequences of this condition are the intestinal extensions leading to malabsorption and malnutrition [2]. The only currently effective health strategy for affected consumers is to avoid glutencontaining products, and such the food must be labelled clearly. However, despite unanimously accepted Codex definitions by all member jurisdictions, the national implementation of equivalent laws displays significant variations. With reference to CD and in support of the gluten-free statement, regulatory enforcement, as well as manufacturers’ quality controls are typically centered and rely on analytical results. The market for the gluten free is expanding and needs to develop and further improve the detection methods for gluten is of paramount importance. Currently, commercially available antibody-based assays are designed to detect gluten to verify and support gluten-free claims in the context of CD. However, these assays are not developed for the purpose of detecting gluten-containing cereals in the context of food allergies. The other wheat allergens which are water soluble like globulins and albumins are also targeted by commercial ELISA kits. Secondly, there are no thresholds established for food allergens, and the lower limit of Quantification (LOQs) of commercial assays for gluten may not be suitable for testing of allergen. Additionally, there is a gap between gluten free definition and food allergen labeling regulation. For example, gluten-free definitions state the reporting unit as mg gluten/kg product, which is used by the kits. However, food allergen labeling regulations mandate the common name of the cereal to be labeled. Commercial assays report only gluten with no conversion factor from gluten to cereal available [3]. Moreover, because currently available kits indistinguishably detect gluten from wheat, rye, and barley, it is not possible to identify the source of cereal. However, it is to be noted that not all food allergen regulations mandate the labeling of gluten-containing cereals as is the case in Europe and Australia. The United States requires only wheat, and Canada requires wheat and triticale. Japan does, not have gluten-free regulations, but requiring the labeling of the presence of wheat and buckwheat as allergens on the food label. In Japan, they use commercial kits to determine and quantify the presence of soluble wheat protein. It is reasonable to state that, Japanese kits are used to determine the presence of wheat in the context of food allergies in accordance with local regulation food allergies.