Understanding the Standard: How much gluten is classed as gluten-free?

October 22, 2025 •

4 min read

According to the FDA, products labeled 'gluten-free' must contain less than 20 parts per million (ppm) of gluten. This standardized definition is crucial for individuals with celiac disease or gluten sensitivity, and it directly answers the question, How much gluten is classed as gluten-free?

Quick Summary

The international standard for gluten-free labeling is under 20 parts per million (ppm), a scientifically derived limit deemed safe for most celiac patients. Different rules apply to third-party certifications, hydrolyzed or fermented items, and manufacturers must prevent cross-contact.

Key Points

20 ppm Standard: The FDA defines 'gluten-free' as containing less than 20 parts per million (ppm) of gluten, a level scientifically determined to be safe for most people with celiac disease.
Cross-Contact is a Major Risk: Gluten cross-contact is the unintentional transfer of gluten to a gluten-free food, which can happen in shared kitchens or manufacturing facilities. Unlike bacteria, gluten cannot be 'killed' by heat.
Third-Party Certification for Extra Assurance: Independent organizations often enforce stricter gluten limits, sometimes as low as 10 ppm, and require regular audits and testing, providing added confidence for highly sensitive individuals.
Special Rules for Oats and Fermented/Hydrolyzed Foods: Oats must be specifically labeled gluten-free due to high cross-contact risk, while fermented and hydrolyzed products follow a records-based approach to prove gluten-free source materials.
Nutritional Awareness is Key: A gluten-free diet can be low in fiber and B-vitamins if not properly managed, so it's important to focus on nutrient-dense, naturally gluten-free foods.
Always Read Labels and Question Preparation: Vigilance in reading labels and questioning food preparation methods is vital, as cross-contact can occur in unexpected places like condiments or buffets.

What is the 20 ppm Standard?

The term "gluten-free" is regulated by government bodies like the U.S. Food and Drug Administration (FDA) and the Codex Alimentarius Commission. This regulation defines 'gluten-free' foods as those containing less than 20 parts per million (ppm) of gluten. This threshold is not arbitrary; it's based on scientific research and represents the lowest level that can be consistently detected using validated analytical methods. A concentration of 20 ppm means there are 20 milligrams of gluten for every kilogram of food. For the vast majority of individuals with celiac disease, research has shown that consuming products below this 20 ppm limit does not cause intestinal damage over time.

Why Not Zero ppm?

The idea of a complete zero-tolerance for gluten is, in practice, nearly impossible for processed foods due to the potential for cross-contact during various stages of food production. Even with the strictest protocols, trace amounts may be unavoidable. The 20 ppm threshold balances scientific detection capabilities with a safe level of consumption for most sensitive individuals. A "zero" ppm standard could also make gluten-free products prohibitively expensive and less accessible.

The Problem of Cross-Contact

Cross-contact is a significant concern in the production and preparation of gluten-free foods. This occurs when a gluten-free food comes into contact with gluten-containing foods, ingredients, or surfaces, making it unsafe for a person with celiac disease. Unlike bacterial cross-contamination which can be eliminated with heat, gluten is a protein that cannot be destroyed by cooking.

Common sources of cross-contact include:

Shared equipment: Using the same cutting boards, toasters, or fryers for both gluten and gluten-free items.
Airborne flour: Flour particles can remain in the air for extended periods in bakeries or shared kitchens and settle on gluten-free foods.
Shared condiments: Double-dipping a utensil into shared jars of spreads like butter, peanut butter, or mayonnaise.
Bulk bins: Shared scoops in store bulk bins for grains, nuts, and spices can easily transfer gluten.

For those in a mixed household or dining out, diligent steps are necessary to mitigate this risk. This includes using separate and clearly labeled utensils, cutting boards, and storage containers for gluten-free items.

FDA vs. Third-Party Certification

While the FDA sets the mandatory standard for voluntary "gluten-free" labeling, some manufacturers opt for additional third-party certification. This provides a greater level of assurance for consumers with high sensitivity.


Aspect	FDA Gluten-Free Labeling	Third-Party Certification (e.g., GFCO)
Gluten Limit	Less than 20 ppm	Often stricter (e.g., 10 ppm or less).
Oversight	Regulatory agency (FDA)	Independent, non-governmental organization.
Verification	Manufacturers are responsible for compliance; enforcement is often reactive, triggered by consumer complaints.	Requires regular audits, facility inspections, and testing.
Manufacturing Standards	Manufacturers must prevent cross-contact to meet the 20 ppm limit.	Often includes more stringent protocols for sourcing and handling ingredients.
Cost	No additional certification fees for manufacturers.	Involves annual fees and testing expenses.

Special Considerations for Fermented and Hydrolyzed Foods

Fermented or hydrolyzed foods and beverages, such as soy sauce, yogurt, or certain beers, require special attention. Standard testing methods may not be able to accurately detect and quantify gluten remnants in these products because the fermentation or hydrolysis process breaks down the gluten protein. In 2020, the FDA addressed this with a final rule requiring manufacturers to demonstrate that the starting ingredients were gluten-free before fermentation or hydrolysis. For distilled products like spirits, the distillation process itself removes gluten.

The Gluten-Free Diet: What to Know Beyond the Label

Following a gluten-free diet is a medical necessity for those with celiac disease, but it requires careful nutritional planning. Many gluten-free substitutes are not fortified with the same nutrients found in conventional products, potentially leading to deficiencies.

Key nutrients to monitor on a gluten-free diet include:

Fiber: Many gluten-containing whole grains are high in fiber. Replacing them with naturally gluten-free sources like fruits, vegetables, beans, and seeds is essential.
B-vitamins (Folate, Thiamin, Riboflavin, Niacin): Enriched wheat flours are a major source of these vitamins. Choosing fortified gluten-free products or consuming fortified cereals and whole grains can help.
Iron, Calcium, Zinc: These can be low in a poorly planned gluten-free diet. A dietitian can recommend dietary changes or supplements to address potential deficiencies.

Consulting a registered dietitian specializing in celiac disease can help create a balanced and nutritious meal plan.

Conclusion

The question of how much gluten is classed as gluten-free has a clear and critical answer: less than 20 parts per million, according to the FDA. However, this standard is just one piece of the larger nutritional puzzle for individuals managing gluten-related disorders. Understanding the legal definitions, the risks of cross-contact, and the differences between FDA-labeled and third-party certified products is crucial for maintaining a safe and healthy diet. By being vigilant about food preparation and label reading, individuals can confidently navigate a gluten-free lifestyle while addressing potential nutritional deficiencies. The availability of clear standards allows people with celiac disease to eat more safely, and ongoing awareness of cross-contact issues further empowers informed dietary choices.

Beyond Celiac provides additional resources for avoiding cross-contact in home and restaurant settings.

Frequently Asked Questions

20 ppm means a food contains 20 milligrams of gluten per kilogram of the finished product. This is a very small, trace amount that is considered a safe threshold for most people with celiac disease.

The 20 ppm standard was chosen because it represents the lowest level that can be reliably and consistently detected using scientifically validated methods. Research also indicates that this level is safe for most individuals with celiac disease, and attempting a "zero" standard would likely increase costs and limit product availability.

"Wheat-free" means a product contains no wheat, but it may still contain other gluten-containing grains like barley or rye. "Gluten-free" means it must contain less than 20 ppm of gluten from any source, including wheat, barley, and rye.

Yes. While pure oats are naturally gluten-free, they are at a high risk for cross-contact with wheat, barley, and rye during growing and processing. Only packaged oats specifically labeled "gluten-free" or "certified gluten-free" are considered safe for those avoiding gluten.

To prevent cross-contact at home, use separate and clearly marked equipment like toasters, cutting boards, and colanders. Opt for squeeze bottles for shared condiments, and store gluten-free items on separate shelves, preferably higher up.

The FDA's rule applies to packaged foods but recommends that restaurants making a gluten-free claim adhere to the same definition. It is crucial to always ask detailed questions about a restaurant's preparation methods to confirm they can prevent cross-contact.

A poorly planned gluten-free diet may be low in fiber, B-vitamins (folate, thiamin, riboflavin), iron, calcium, and zinc. It's important to focus on naturally gluten-free foods like fruits, vegetables, and legumes, or choose fortified gluten-free products.