Avoiding Gluten Cross-Contamination

Avoiding exposure at home, restaurants, and grocery stores

Your own kitchen may be a source of gluten cross-contamination. Getty Images/Tim Pannell

For people starting the gluten-free diet, it often comes as a surprise at just how little gluten it takes to make you sick. It's also surprising to learn that gluten can hide in many different places in your diet, and you won't necessarily know it's there until later when you get sick.

Gluten cross-contamination can occur during any stage of food preparation. It can happen your own kitchen, in restaurants, or even in packaged foods that are labeled "gluten-free."

Fortunately, there are simple ways to help safeguard against this and minimize your exposure to gluten cross-contamination. Here's a list of recommended ways to ensure you stay gluten-free.

Keep a Gluten-Free Kitchen

Starting the gluten-free diet requires more than just recipes. You will often need to safeguard your kitchen against accidental exposure. Of course, this can be a tough prospect if there are other family members or roommates involved.

If you're living with others, you may need to set up a "safe zone" to ensure utensils, appliances, and even refrigerator space are safe from contamination. Among the key considerations:

  • Using an old toaster is one of the most common sources of gluten cross-contamination. You may need to get one for yourself, and if you do, never let anyone put bread that's made with gluten grains in it.
  • Only buy stainless steel or solid aluminum pans that do not have nonstick coating. When washed properly, these pans can be used to prepare both gluten and gluten-free foods (so long as the foods are not prepared together).
  • If you're using nonstick pans, keep in mind they develop scratches over time which can potentially harbor gluten. You might be better off replacing a nonstick pan after a few years if it becomes scratched, or just sticking with pans that are not finished with a nonstick coating.
  • Replace old cast iron pans and pizza stones that were used to make gluten foods, and avoid using the new ones for gluten foods.
  • Buy a non-porous cutting board to be used exclusively for non-gluten food preparation.
  • Metal cooking utensils are better at preventing cross-contamination than wooden ones (and even some silicone or plastic ones).
  • Be careful about sponge and scrubbers used to wash dishes. Try to keep one exclusively for your pots, pans, and utensils, and separate ones for everyone else.

Choose Restaurants Wisely

Many restaurants do a decent job of producing gluten-free meals for customers with celiac disease and non-celiac gluten sensitivity. However, unless a restaurant is strictly gluten-free, the majority of establishments will prepare gluten-free foods in the same kitchen as gluten foods, and in many instances, with the same utensils as everything else, which puts you at risk for cross-contamination.

If you are especially sensitive to trace amounts of gluten, you may need to decide if it's safer to eat at home versus dine out. Outside of major cities, there aren't many 100% gluten-free restaurants. If you don't have a strictly gluten-free establishment near you, you may want to contact the chef or kitchen manager at the restaurants in your area that cater to the gluten-free community in advance of your visit. The two main things you would want to know are:

  • Has your kitchen staff received specific training in avoiding gluten cross-contamination?
  • Are all gluten-free foods made onsite? If not, which ones would I need to avoid?

Based on their responses, you can usually get a pretty good idea as to how gluten-free the menu items actually are.

In some cases, chain restaurants may have stricter gluten-free guidelines in place than independent establishments, since they tend to have more regimented training systems and protocols.

Don't Always Assume Labels are Safe

Gluten-free foods have become a big business and those with gluten-intolerance have more options than ever before. According to data from the Gluten-Free Products Market Analysis, the gluten-free food industry in the U.S. was valued at 4.7 billion in 2019, and is projected to reach 8.5 billion by the year 2027. Despite the surge in foods labeled gluten-free, however, there's still a chance that traces of gluten can be found in them.

Given the prevalence of gluten intolerance and celiac disease, the U.S. Food and Drug Administration (FDA) requires that foods labeled gluten-free must contain less than 20 parts per million (ppm). But it's important to understand that gluten-free food labeling is also voluntary, and that not all manufacturers are required to label their gluten-free products as such, even if they fall below 20 ppm. The FDA regulation asserts that manufacturers that do label their products gluten-free must adhere to the guidelines. However trace amounts of gluten can still sneak into many gluten-free labeled foods, since testing for gluten is not always verifiable.

As a result, many people will rely on a company's brand name and reputation when they make their purchases, which is usually a pretty good way to go since many 100% gluten-free companies are focused and dedicated to making safe and reliable gluten-free foods. That's because for those who are particularly sensitive, 20 ppm may still be too much. If that's the case for you, look for foods that are labeled "Certified Gluten-Free" by the Gluten Free Certification Organization (GFCO), which tests products to 10 ppm or less.

Other companies may offer a special gluten-free product line in addition to their products containing gluten. This usually suggests that the kitchen and manufacturing facility is operated within stringent standards to prevent accidental cross-contamination. Most companies will disclose if a gluten-free product is produced in the same facility that also processes gluten grains like wheat. If you hesitate when you're faced with a new product, take the time to read the ingredients on the label carefully, or stick with products that bear the official "Certified Gluten-Free" logo.

While companies aren't required by the FDA to disclose a risk of cross-contamination for gluten since accurate testing is not yet available, they are required to do so for the top eight food allergens which includes wheat as well as milk, eggs, peanuts, tree nuts, soy, fish, crustacean, and shellfish, under the Food Allergen Labelling and Consumer Protection Act (FALCPA).

The simple rule of thumb is this: if you're uncertain about a gluten-free product and the label does warn of possible cross-contamination from wheat or other gluten grains, you may want to try something else.

A Word from Verywell

As you can see, following the gluten-free diet can be complicated and involves more than just making sure you eat only foods with a gluten-free label. Gluten cross-contamination is an issue for those who are especially sensitive to trace amounts of gluten, and one that can potentially make you sick despite that you thought you were eating gluten-free.

If you find yourself really struggling, talk to your doctor about getting a referral to a dietitian who specializes in the gluten-free diet. That person can help you identify sources of gluten cross-contamination so that you can eliminate them.

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