The FDA Gluten-Free Rule: 20 ppm

In 2013, the FDA finalized a rule under 21 CFR 101.91 establishing that any food product bearing a "gluten-free," "free of gluten," "without gluten," or "no gluten" label claim must contain less than 20 parts per million (ppm) of gluten.[1]

The 20 ppm threshold was selected for two reasons. First, it represents the lowest level that can be reliably and consistently detected using validated scientific methods. Second, it is the threshold at which most clinical research indicates the majority of people with celiac disease can consume gluten without intestinal damage occurring.[2]

FDA Definition

Under 21 CFR 101.91, gluten-free means: inherently gluten-free; or does not contain an ingredient that is a gluten-containing grain; or does not contain an ingredient derived from a gluten-containing grain that has not been processed to remove gluten; or if it does contain such an ingredient, the food must contain less than 20 ppm gluten.

What Is Gluten?

Gluten is a family of proteins — primarily gliadin and glutenin — found naturally in wheat, barley, rye, and their derivatives.[3] Oats are naturally gluten-free but are frequently contaminated during growing and processing. Gluten gives bread dough its elasticity and is also used as a stabilizer and thickener in many processed foods including soy sauce, salad dressings, deli meats, and soups.

For people with celiac disease — an autoimmune condition affecting approximately 1% of the global population — ingesting gluten triggers an immune response that damages the small intestine lining.[4] For people with non-celiac gluten sensitivity, the mechanism is different but symptoms can be equally disruptive.

Third-Party Certifications: Beyond the FDA Label

The FDA rule sets a legal minimum, but manufacturers are not required to test their products to verify compliance — they simply must be able to demonstrate compliance if the FDA investigates. Third-party certification programs add an independent verification layer, including mandatory testing and facility audits.

Gluten-Free Certification Organization (GFCO)

The GFCO, a program of the Gluten Intolerance Group (GIG), is the largest gluten-free certification body in North America.[5] GFCO sets a stricter threshold of 10 ppm — half the FDA standard — and requires annual facility inspections and product testing. Their circular wheat-head logo appears on over 60,000 products globally.

NSF International Gluten-Free Certification

NSF International, an American public health and safety organization, offers gluten-free certification that requires products to test at or below 20 ppm (matching the FDA standard) with mandatory annual product testing and facility audits.[6] NSF certification is particularly common in the dietary supplement and sports nutrition categories.

Gluten-Free Food Service (GFFS)

GFFS provides certification specifically for food service operations — restaurants, cafeterias, and catering companies — rather than packaged products. GFFS-certified establishments have documented protocols for preventing cross-contamination in food preparation environments.

CertificationThresholdFacility AuditMandatory Testing
FDA Label Rule< 20 ppm✗ No✗ No
GFCO< 10 ppm✓ Annual✓ Yes
NSF Gluten-Free< 20 ppm✓ Annual✓ Yes

Gluten-Free vs. Celiac-Safe: The Distinction That Matters

A "gluten-free" label — even a certified one — does not guarantee a product is safe for every person with celiac disease. Several factors complicate this:

  • Individual sensitivity varies: Some celiac patients react to levels well below 20 ppm. Research suggests approximately 5% of celiac patients may react to gluten levels between 1–5 ppm.[7]
  • Cross-contamination in the home: A certified gluten-free product introduced into a kitchen where gluten-containing foods are prepared can become contaminated through shared utensils, toasters, or cutting boards.
  • Oat sensitivity: A subset of celiac patients react to avenin, the protein in oats, even when oats are certified gluten-free. Certified gluten-free oats are not automatically safe for all celiac patients.
Medical Guidance Required

People with celiac disease should work with a gastroenterologist and registered dietitian to determine their individual tolerance. TheGoodFilter provides product information only — not medical advice.

How We Score Gluten-Free on The Goods Filter

For food products sourced from Open Food Facts, we detect gluten-free status from the labels_tags field. When a product carries the en:gluten-free tag — typically derived from packaging claims contributed by the Open Food Facts community — we assign a confidence score of 0.85.

Confidence threshold85%

The 85% threshold reflects that gluten-free tags in Open Food Facts are binary — the label is either present or absent based on the product's packaging. We do not distinguish between FDA-labeled and third-party certified products within the tag data. A present gluten-free tag earns 0.85 confidence; absent earns 0.

Frequently Asked Questions

What is the FDA gluten-free standard?

The FDA's 2013 gluten-free labeling rule (21 CFR 101.91) requires that any food bearing a gluten-free claim must contain fewer than 20 parts per million (ppm) of gluten. This threshold was chosen as the lowest reliably detectable level that is generally safe for most people with celiac disease. Manufacturers are not required to test products but must be able to demonstrate compliance.

Is oats gluten-free?

Oats are naturally gluten-free, but most commercial oats are contaminated with wheat, barley, or rye during growing, transport, or processing. Products labeled "gluten-free oats" or "certified gluten-free oats" are produced under purity protocols to prevent cross-contamination. Even so, a subset of celiac patients may react to the avenin protein in oats regardless of certification status.

What is the difference between gluten-free and wheat-free?

"Wheat-free" only indicates the absence of wheat — it does not address barley, rye, or their derivatives, all of which contain gluten. A wheat-free product can still contain significant gluten from barley malt syrup, rye flour, or triticale. "Gluten-free" under the FDA standard covers all gluten-containing grains and their derivatives and must fall below 20 ppm total gluten from any source.

Can a gluten-free label appear on naturally gluten-free foods?

Yes. The FDA allows naturally gluten-free foods — like fresh produce, plain meat, and most dairy products — to carry a gluten-free label if they meet the under-20 ppm standard. This can be informative about cross-contamination controls in manufacturing but does not indicate special processing. Some consumers find the label reassuring on products like canned beans or rice that are naturally gluten-free but manufactured in facilities that also handle wheat.

Footnotes
  1. 1U.S. Food and Drug Administration. (2013). Gluten-Free Labeling of Foods: Final Rule. 21 CFR Part 101. https://www.fda.gov/food/nutrition-food-labeling-and-critical-foods/gluten-free-labeling-foods ↩
  2. 2Akobeng, A. K., & Thomas, A. G. (2008). Systematic review: tolerable amount of gluten for people with coeliac disease. Alimentary Pharmacology & Therapeutics, 27(11), 1044–1052. https://pubmed.ncbi.nlm.nih.gov/18315587/ ↩
  3. 3National Institutes of Health — National Institute of Diabetes and Digestive and Kidney Diseases. (2024). Celiac Disease: Definition & Facts. https://www.niddk.nih.gov/health-information/digestive-diseases/celiac-disease/definition-facts ↩
  4. 4Fasano, A., Berti, I., Gerarduzzi, T., Not, T., Colletti, R. B., Drago, S., … Horvath, K. (2003). Prevalence of celiac disease in at-risk and not-at-risk groups in the United States. Archives of Internal Medicine, 163(3), 286–292. https://pubmed.ncbi.nlm.nih.gov/12578508/ ↩
  5. 5Gluten Intolerance Group. (2024). GFCO Certification Program Overview. https://www.gluten.org/gfco/ ↩
  6. 6NSF International. (2024). Gluten-Free Certification Program. https://www.nsf.org/consumer-resources/articles/gluten-free-certification ↩
  7. 7Catassi, C., Fabiani, E., Iacono, G., D'Agate, C., Francavilla, R., Biagi, F., … Fasano, A. (2007). A prospective, double-blind, placebo-controlled trial to establish a safe gluten threshold for patients with celiac disease. American Journal of Clinical Nutrition, 85(1), 160–166. https://pubmed.ncbi.nlm.nih.gov/17209192/ ↩

References