5 Hidden Sources of Gluten That Could Be Costing You Loyal Guests

In today’s dining landscape, offering gluten-free options isn’t just a trend—it’s a necessity. With an estimated 1 in 100 people diagnosed with celiac disease and millions more living with gluten sensitivities, guests are actively seeking restaurants they can trust. But even with a “gluten-friendly” menu, small mistakes or overlooked ingredients can damage that trust and cost you loyal customers.

The challenge? Gluten is sneaky. It hides in ingredients and preparations that many chefs and operators don’t suspect. A single oversight can turn a promising guest experience into a bad review, or worse, a health scare. Here are five hidden sources of gluten that could be quietly sabotaging your efforts.

1. Sauces, Dressings, and Marinades

Many pre-made sauces, salad dressings, and marinades contain gluten as a thickening agent or flavor enhancer. Ingredients like malt vinegar, soy sauce, or modified food starch (derived from wheat) are common culprits. Even seemingly harmless items like Worcestershire sauce or teriyaki can be loaded with gluten. The fix? Make sauces and dressings in-house when possible or source certified gluten-free products. Always review labels carefully and educate your staff on safe substitutions.

2. Fryer Cross-Contamination

Your French fries may be naturally gluten-free, but if they share oil with breaded chicken tenders or onion rings, they’re off-limits for celiac guests. Cross-contamination in fryers is one of the most common and frustrating problems for gluten-free diners. Guests who get sick from this mistake may never return—and they’ll likely warn others. A dedicated fryer or air fryer for gluten-free items can make all the difference.

3. Spice Blends and Seasoning Packets

Pre-mixed spice blends, rubs, and seasoning packets often include anti-caking agents or fillers like wheat flour. Even something as simple as a taco seasoning packet can contain gluten. This hidden risk is particularly dangerous because it’s not something guests—or even your cooks—would suspect. Stick to single-ingredient spices or create your own blends in-house to guarantee they’re gluten-free.

4. Imitation Meats and Seafood

Surimi (imitation crab) and other processed meats often use wheat-based binders. While popular in sushi rolls, seafood salads, and some pasta dishes, these ingredients are far from safe for gluten-free guests. Even plant-based meat alternatives like veggie burgers or faux chicken strips may contain gluten unless specifically labeled gluten-free. Always verify the ingredients with suppliers.

5. Beer, Malt, and “Natural Flavors”

Beer-battered dishes and malt-based ingredients are obvious gluten sources, but did you know some “natural flavors” also come from barley or wheat derivatives? Items like malted milkshakes, certain vinegars, or even candies may sneak gluten into your kitchen. When in doubt, ask vendors for ingredient statements or certifications.

The Bottom Line

Offering gluten-free menu items isn’t enough—you need to back them up with strict ingredient control and staff education. Guests with celiac disease or sensitivities rely on your attention to detail. A single hidden gluten source can damage trust and cost you repeat business.

Want to build a reliable gluten-free menu that earns guest loyalty? A consultant can audit your recipes, vendors, and processes to eliminate risks and ensure your guests feel safe—and eager to return.