How can you tell if something is gluten-free?

December 5, 2025 •

4 min read

According to the FDA, any food labeled "gluten-free" must contain less than 20 parts per million of gluten. But relying solely on this claim isn't enough; knowing how can you tell if something is gluten-free requires careful label reading and awareness of hidden ingredients and cross-contamination risks.

Quick Summary

This guide provides a comprehensive overview of how to identify gluten-free products by reading food labels, understanding allergen statements, and recognizing official certifications. It also covers the importance of preventing cross-contamination in kitchens and identifying naturally gluten-free foods.

Key Points

Check for Certifications: Look for third-party symbols like GFCO or the Crossed Grain symbol for the most reliable gluten-free assurance.
Read All Labels: Always read the ingredients and allergen statements, even on products with a "gluten-free" claim, due to voluntary regulations.
Beware Hidden Sources: Gluten can lurk in common additives, flavorings, sauces, and processed meats, so scrutinize ingredients carefully.
Prevent Cross-Contamination: At home, use separate equipment and follow strict storage rules to avoid accidental gluten exposure.
Identify Naturally Safe Foods: Focus on naturally gluten-free foods like fresh produce, unprocessed meats, and legumes to build a safe diet.
Be Vigilant with Oats: Only consume oats that are specifically labeled certified gluten-free, as they are high-risk for contamination.

Reading Food Labels for Gluten-Free Claims

For those with celiac disease or gluten sensitivities, the food label is the most important tool for safety. While a “gluten-free” claim is a great starting point, a savvy consumer must dig deeper. In the U.S., the FDA regulates the use of the term "gluten-free" and requires that any product bearing this claim must contain less than 20 parts per million (ppm) of gluten. However, this is a voluntary claim, and manufacturers are not required to test for gluten to use it.

Three key steps to reading a label effectively:

Check for a Certified Gluten-Free Symbol: The most reliable way to identify a safe product is to look for a third-party certification mark, such as the GFCO (Gluten-Free Certification Organization) or the AOECS Crossed Grain symbol. These marks mean the product has been tested to a stricter standard (often 10 ppm or less) and the manufacturing facility undergoes regular audits.
Analyze the Allergen Statement: The Food Allergen Labeling and Consumer Protection Act (FALCPA) mandates that major allergens be declared. Look for a "Contains: Wheat" statement, which will immediately rule out a product. However, remember that FALCPA does not require the listing of barley or rye, so their absence doesn't guarantee safety.
Review the Ingredient List: Even with a "gluten-free" label, it is crucial to scan the full ingredient list for any potential sources of gluten, particularly hidden ones. Manufacturers sometimes use an ingredient derived from a gluten-containing grain that has been processed to remove gluten, and if the final product is still under 20 ppm, it can be labeled gluten-free.

Deciphering Hidden and Obvious Gluten Sources

Recognizing the obvious sources of gluten is straightforward, but many less-obvious ingredients can also hide gluten. A thorough understanding of these is essential for a strict gluten-free diet.

Grains to Always Avoid (unless certified gluten-free):

Wheat (including spelt, farro, kamut, durum, semolina)
Barley
Rye
Malt (malt extract, malt flavor, malt vinegar)
Brewer's yeast
Oats (unless specifically certified gluten-free due to high cross-contamination risk)

Common Sources of Hidden Gluten:

Additives: Modified food starch, dextrin, maltodextrin (unless labeled 'from corn')
Flavors: Natural and artificial flavors, smoke flavoring (can be derived from barley)
Sauces and Seasonings: Soy sauce, marinades, salad dressings, and spice mixes often contain wheat or gluten
Processed Meats: Sausage, hot dogs, and deli meats can use binders and fillers that contain gluten
Medications and Supplements: Gluten can be used as a binding agent, so always check with your pharmacist

Understanding Cross-Contamination

Cross-contamination is a serious risk where gluten-free food comes into contact with gluten-containing food, surfaces, or utensils. This can happen in restaurants, at home, and even during the manufacturing process.

Preventing Cross-Contamination at Home

Use separate equipment: Have dedicated items like toasters, cutting boards, and colanders for gluten-free foods.
Store food properly: Keep gluten-free items on a separate shelf above gluten-containing foods to prevent crumbs from falling.
Designate clean zones: Clean countertops thoroughly before preparing gluten-free food, especially if flour is used in the same kitchen.
Manage shared condiments: Use squeeze bottles or dedicated jars of butter, jam, or spreads to prevent crumbs from double-dipping.

Comparison of Certified vs. Uncertified Products


Feature	Certified Gluten-Free Product	Uncertified Product
Gluten Level	Often tested to a stricter standard (e.g., <10 ppm for GFCO).	Must meet FDA standard of <20 ppm, but testing is not required.
Manufacturing Risk	Facility undergoes regular third-party audits to prevent cross-contamination.	Relies on manufacturer's self-regulation. Risk of cross-contamination is higher, especially if made on shared lines.
Trust and Reliability	Carries an internationally recognized symbol, providing high consumer confidence.	Consumers must rely on voluntary claims and careful label reading. Higher risk of accidental exposure.
Oats	Only oats processed under a "purity protocol" are used to avoid contamination from field to production.	Oats are highly susceptible to cross-contamination unless specifically labeled as gluten-free.

Naturally Gluten-Free Foods

Many foods are naturally free of gluten and form the basis of a healthy, gluten-free diet. These items are generally safe unless they have been processed or come into contact with gluten through cross-contamination.

Naturally gluten-free food list:

Fresh fruits and vegetables
Unprocessed meats, poultry, and fish
Eggs
Legumes, nuts, and seeds (in their natural, unprocessed forms)
Most low-fat dairy products like plain milk and yogurt
Rice and corn

Conclusion

Navigating a gluten-free diet requires diligence and education. By consistently checking labels, looking for certification marks, and understanding potential sources of cross-contamination, you can ensure your food is safe. Relying on certified products from trusted brands is the most secure method, but reading every ingredient list is a non-negotiable habit. For more information, consult the Celiac Disease Foundation's guide to label reading. With a little practice, you'll become an expert at knowing how can you tell if something is gluten-free and enjoy your meals with confidence.

Frequently Asked Questions

No, "wheat-free" is not the same as "gluten-free." While wheat is a source of gluten, other grains like barley and rye also contain gluten. A wheat-free product may still contain barley or rye, making it unsafe for a gluten-free diet.

Bulk bins should generally be avoided for a gluten-free diet. Shared scoops and proximity to other gluten-containing items create a high risk of cross-contamination from airborne flour and careless customers.

Only consume oats that are specifically labeled and certified gluten-free. Standard oats are often cross-contaminated during harvesting, transportation, and processing due to shared equipment with wheat, barley, and rye.

Restaurants offering gluten-free options require careful questioning. Ask staff about specific preparation methods, ingredient sourcing, and how they prevent cross-contamination in the kitchen, including using separate surfaces, fryers, and utensils.

The FDA defines "gluten-free" as containing less than 20 ppm of gluten. This is the lowest level consistently detectable with modern scientific methods and is considered safe for most individuals with celiac disease.

Yes, some medications and dietary supplements can use gluten as a binding agent. It is important to talk with your healthcare provider or pharmacist and check the ingredients list to confirm if a product is safe.

Standard beer, ale, and other malted beverages brewed with barley are not gluten-free. While some alcohol is distilled from gluten grains, many brands are explicitly labeled gluten-free. Check the label carefully; a "gluten removed" claim is not safe for those with celiac disease.

"May contain" statements are voluntary and unregulated by the FDA, indicating a risk of cross-contamination. While products with a certified gluten-free label should still be safe, many people with celiac disease choose to avoid products with this advisory if they are not certified.