Development and Validation of a Novel Gluten Detection Lateral-flow Device

Introduction: To address growing public health concerns regarding gluten intolerance, the FDA has established regulatory threshold limits for gluten content in foods labeled "gluten-free." Implementation of these labeling laws requires antibody based methodologies that can accurately quantify gluten levels. To address the growing need for rapid and accurate detection of gluten residues, we developed a Lateral Flow test method capable of detecting wheat, barley, and rye gluten residues at near equal levels down to 0.1 mg/swab and 1.0 ppm for food samples.

Purpose: To develop a rapid, sensitive, and reliable qualitative test method for detecting gluten residues obtained from environmental and food samples. 

Methods: Polyclonal antibodies were raised against prolamin fractions derived from wheat, rye, and barley. The polysera from these individually immunized goats were immuno-purified and then blended. The antibodies were then used to develop a lateral flow test device (LFD) for detection of gluten from wheat, barley, and rye, configured with a test line, an overload line, and a procedural control. A test method was developed using a novel extraction buffer and a rapid extraction step (1 min at 95°C), and visualization after 15 min of running. Validation was performed to define test parameters and method concordance studies were performed using commercial ELISA kits based on R5 and Skerrit mAbs.

Results: The test method relies on a 1 min extraction at 95°C and an assay read at 15 min. The LOD for the device was determined as 0.1 ppm /swab and 1.0 ppm or food samples based on gliadin. The test was highly specific for prolamin residues derived from a panel of wheat, barley, and rye varieties, and did not cross-react with avenins isolated from R5(-) oats, sorghum, rice, soy, corn, millet or rice. The LFD was reproducibly more sensitive than the commercial ELISA kits, allowing for robust presumptive screening.

Significance: The MEI/IEH gluten test provides a rapid, highly specific, and extremely sensitive detection system for use in the food industry as part of routine HACCP monitoring and screening for gluten.