Gluten

Gluten is a family of proteins found in wheat, barley, rye and crossbreeds such as triticale. It gives dough its elasticity, but for people with celiac disease or gluten sensitivity it must be avoided. Because gluten also arrives through shared equipment and hidden ingredients, a gluten-free label claim is defined by a measured limit — under 20 parts per million under the FDA rule.

In depth

The proteins usually grouped as gluten are gliadin and glutenin in wheat, with related proteins in barley (hordein) and rye (secalin). An estimated 1 in 100 people worldwide have celiac disease (Celiac Disease Foundation, checked 2026), and others avoid gluten for non-celiac sensitivity.

Gluten hides beyond obvious grains — in malt, brewer's yeast, some starches and thickeners, soy sauce, and enzymes or processing aids grown on wheat. It also transfers through cross-contact on shared lines.

Under the U.S. FDA rule (21 CFR 101.91) a product may be labeled gluten-free only if it contains under 20 parts per million of gluten. A V-Cert gluten-free certificate states the exact threshold the product was tested against, and the review covers ingredients, supplier declarations and contact controls.

Related marks

• Gluten-FreeNot built for retailers mandating GFCO specifically — if yours does, we'll tell you before you pay anything.

Related terms

• Parts per million (ppm) — Parts per million (ppm) is a unit for very small concentrations, equal to one milligram of a substance per kilogram of product.
• Cross-contact — Cross-contact is the unintended transfer of an allergen or gluten from one food to another, usually via shared equipment, hands or airborne particles.
• Allergen — A food allergen is a substance, usually a protein, that can trigger a harmful immune response in sensitive people and must be declared under labeling law.

Frequently asked questions