Behind the Scenes: How Gluten-Free Food is Really Made in a Dedicated Factory
As someone who has lived with coeliac disease for 17 years, I've spent a lot of time reading labels, researching brands, and wondering, what does it actually take to produce food that is genuinely safe for coeliacs? How do manufacturers ensure that what's in the packet really is gluten-free?
I decided to dig into the facts. Here's what really goes on inside a dedicated gluten-free food facility.
What Does "Dedicated Gluten-Free" Actually Mean?
A dedicated gluten-free facility is one where no gluten-containing ingredients are ever brought into the building. This is distinct from a "gluten-free line" within a shared factory, where allergen controls must work much harder to prevent cross-contamination.
In a fully dedicated site, the risk of airborne gluten particles, shared equipment contamination, or human error involving gluten ingredients is eliminated at source, not just managed.
Under EU and UK food law (Regulation (EU) No 41/2009, retained in UK law post-Brexit), a product can only be labelled "gluten-free" if it contains no more than 20 parts per million (ppm) of gluten. This is the internationally recognised threshold considered safe for the vast majority of people with coeliac disease.
The Machinery: What Makes It Different?
In a gluten-free factory, the equipment is purpose-built or fully dedicated to gluten-free production. Here's what that looks like in practice:
- Sealed mixing and blending systems — Industrial mixers in GF facilities are enclosed to prevent airborne contamination. In bread and flour production, open mixing would risk flour dust spreading through the air, which is a real cross-contamination risk.
- Dedicated conveyor systems — Conveyor belts, hoppers, and chutes are all dedicated to gluten-free production only. These are made from food-grade stainless steel or polyurethane, which are non-porous and easy to clean to validated standards.
- Positive air pressure systems — Many high-spec GF facilities use positive pressure air filtration, meaning air flows outward from the production area rather than inward, reducing the risk of contamination from outside the clean zone.
- HEPA filtration — High-Efficiency Particulate Air (HEPA) filters capture airborne particles including flour dust down to 0.3 microns in size — far smaller than a gluten protein molecule cluster.
- Packaging machinery — Automated sealing and packaging lines minimise human handling and the risk of environmental contamination post-production.
Ingredient Control and Supplier Auditing
It's not just about the factory floor. Rigorous GF manufacturers apply strict controls at every stage of the supply chain:
- Certified gluten-free raw ingredients — Every ingredient entering a dedicated GF facility must come with a certificate of conformance confirming it meets the <20ppm threshold. Suppliers are typically audited annually.
- Segregated storage — Ingredients are stored in clearly labelled, sealed containers in dedicated areas. Even in a GF-only facility, different allergen controls may still apply for other allergens like nuts or dairy.
- Traceability systems — Batch coding and traceability software means that if a contamination issue is identified anywhere in the supply chain, affected products can be rapidly traced and recalled.
Testing: How Do They Know It's Safe?
This is the part I find most reassuring as a coeliac. Reputable manufacturers don't just assume their processes are working, they test, repeatedly.
- ELISA testing — Enzyme-Linked Immunosorbent Assay (ELISA) is the gold standard method for detecting gluten in food. It is highly sensitive and can detect gluten at concentrations well below 20ppm. Finished products are tested per batch or at regular intervals depending on the facility's quality protocols.
- Environmental swab testing — Surfaces, equipment, and air samples are regularly swabbed and tested to confirm there is no gluten present in the production environment.
- Third-party laboratory testing — Many certified GF producers send samples to independent accredited laboratories for verification, separate from their own in-house testing.
Certification: What the Logos Really Mean
You'll often see logos on GF packaging from certification bodies. In the UK and Europe, the most recognised is the Crossed Grain symbol from Coeliac UK, which is licensed to manufacturers who meet strict criteria including:
- Products tested to contain <20ppm gluten
- Robust written procedures for gluten-free production
- Regular independent audits of the facility
In the US, the GFFS (Gluten-Free Food Service) and GFCO (Gluten-Free Certification Organization) logos indicate products tested to <10ppm — an even stricter standard.
It's worth noting that certification is voluntary. A product can legally carry a "gluten-free" claim without third-party certification, as long as it meets the <20ppm legal standard. For coeliacs who are particularly sensitive, opting for certified products with a recognised logo adds an extra layer of assurance.
Why This Matters for Coeliacs
Understanding how food is produced helps us make more informed choices. Not all "gluten-free" labels are equal, the difference between a product made in a fully dedicated facility with third-party certification, versus one produced on a shared line with allergen controls, is significant.
When I'm buying packaged gluten-free products, I look for:
- A recognised certification logo (Crossed Grain, GFCO, etc.)
- Clear labelling about whether it's made in a dedicated facility
- A brand with a transparent allergen policy, ideally published on their website
The more we as coeliacs understand about food production, the better equipped we are to advocate for ourselves and make safe choices.
Claire x
Founder of Gluten Free On The Go