Detection of Gluten by a Reliable ELISA Method

Introduction: In August 2013, gluten-free labeling regulations were enacted and gluten limits for gluten-free foods were established by the Food and Drug Administration (FDA) of the United States. These gluten limits, which were based on Codex standards, allow items with gluten content of less than 20 ppm to be labeled as “gluten-free.” The establishment of these evaluation standards made it possible to measure the gluten content of foods and other products and label them accordingly.

Purpose: To improve usability, Morinaga Wheat/Gluten (Gliadin) ELISA Kit which has been validated as Japanese official allergen analysis method and announced as a gluten determination method of US-FDA Gluten Free Food Labeling Rule was developed two additional application, “Short Time Extraction Method” and “High Range Assay.” “Overnight Extraction Method” which is original extraction method needs over 12 h for extraction, but “Short Time Extraction Method” finishes extraction by heating only 10 min in boiling water. “Recommended Assay” which is original assay is designed assay range between 0.26 to 17 ppm gluten, but “High Range Assay” is expanded assay range between 1.05 to 68 ppm gluten to directly detect 20 ppm gluten. Because gluten-free food generally defined that it contains less than 20 ppm gluten.

Methods: “Short Time Extraction Method” was evaluated by comparing with “Overnight Extraction Method,” and “High Range Assay” was evaluated by comparing with “Recommended Assay.”

Results: “Short Time Extraction Method” showed high extraction ability (96 - 104%) in incurred food analysis and a good correlation with “Overnight Extraction Method” (92 - 105%). “High Range Assay” showed a good correlation with “Recommended Assay” (98 - 126%).

Significance: Two new applications of Morinaga Wheat/Gluten (Gliadin) ELISA Kit provide reliable and more user-friendly gluten analysis method to food industry.