6 Hidden Sources of Gluten in Supermarket Foods

Increasingly, supermarkets are providing lists of gluten-free products, or even labeling foods "gluten-free" right on the shelf. This practice makes it easier for people who are following a gluten-free diet because they have celiac disease or non-celiac gluten sensitivity.

However, there are gluten-free hazards that you probably don't expect. Certain popular foods that you might assume to be gluten-free (or at least free from gluten ingredients), actually contain hidden gluten or carry a significant risk of gluten cross-contamination, simply because of the way they're processed.

These are six hidden sources of gluten that are commonly found in supermarket foods. Learn how to avoid them and what you can buy to replace them in your shopping cart.


Rotisserie Chicken

Whole rotisserie chicken on a plate

Verywell / Alexandra Shytsman

You'd think that the rotisserie chickens sold in grocery stores should be gluten-free. But most are not. The problem is not the chicken, but rather the preparation of the bird.

Many grocery stores add a light dusting of flour on the skin of the chicken to make it crisper. There may also be gluten ingredients in the spices, rub, or sauce used to add flavor.

But even if none of these ingredients is used, cross-contamination in the cooking and packaging of the bird may cause exposure to gluten.

In fact, many stores cook and sell fried chicken right alongside their rotisserie chickens. To stay gluten-free:

  • Purchase a rotisserie chicken from a store that labels it "gluten-free." Costco and Sam's Club are two gluten-free options if you have a membership.
  • Try Boston Market's rotisserie chicken instead of a grocery store version. It's labeled "gluten-free," and you can pick up some gluten-free side dishes while you're there.

Deli Meat and Cheese

It's a gluten-free urban myth that many deli meats contain gluten ingredients as fillers. In the vast majority of cases, deli meats and cheeses are made with gluten-free ingredients. However, that doesn't mean you can safely order deli products sliced to order at the counter.

Some deli products carry a significant risk of gluten cross-contamination.

In addition, you're at risk for plenty of gluten cross-contamination in the deli, due to the fact that the slicing machines aren't cleaned more than once or twice a day, and sandwiches (constructed with wheat-based bread) are made in the deli. To stay gluten-free:

  • Purchase packaged meats that are marked "gluten-free," and stick with pre-packaged sliced cheeses. The vast majority of cheese brands are safe.
  • Buy a brand that's labeled "gluten-free," such as Boar's Head. Also, ask the staff to use a clean machine if you must get meat sliced for you from the deli case.

Soup and Salad Bar

Supermarket-based soup and salad bars often look tempting. They contain fresh, healthy food for a meal that requires little effort on your part. You might convince yourself that you can choose the items that seem gluten-free and leave the "gluten-y" foods behind.

While you might get away with picking and choosing from options that are less likely to contain gluten, the risk of gluten cross-contamination is high.

For example, it is easy for a customer to drop a crouton in the (otherwise gluten-free) ranch dressing, or to dribble a bit of tabbouleh into the quinoa. To stay gluten-free:

  • Choose items that are obviously gluten-free, such as lettuce and raw vegetables.
  • Avoid items that are in bins next to gluten-containing items. For example, avoid the potato salad if it is next to macaroni salad.
  • Skip the soup unless it's clearly labeled "gluten-free."
  • Stick with salad bars in grocery stores that label items "gluten-free" or "no gluten ingredients." Wegmans, a chain in the northeast and mid-Atlantic, does this (and Wegmans sushi is gluten-free).

Packaged Cheese

Most cheese is naturally gluten-free. So people who follow the gluten-free diet can eat it unless they're also sensitive to casein (a milk protein) or other milk-based ingredients. However, you should avoid cheese that have been packaged in the supermarket.

The reason? Most stores have the deli counter package cheese. This area of the store is used to cut sandwiches and other gluten-containing foods. The risk of cross-contamination is high. To stay gluten-free:

  • Talk to deli staff about where they cut up the larger portions of cheese into smaller quantities. If this takes place in the same space as sandwiches are made, steer clear.
  • Avoid packages that are sealed with thin plastic wrap and secured on the back with a store-printed label. Purchase only packages that are shrink-wrapped. Shrink-wrapping occurs off-site in most instances—away from the deli counter. Lastly, confirm with store workers that the cheese was not packaged in the store.

Bulk Bins

It's so tempting to buy products out of the bulk bins in supermarkets, health food stores, and co-ops. The items generally are much less expensive than packaged goods.

But bulk bins hold special risks for people who need to follow a gluten-free diet. Customers share scoops between the bins, putting you at risk for cross-contamination.

For example, a customer might scoop almonds with a tool that previously was used for whole wheat flour—leaving a residue on the almonds. Also, store workers don't always clean the bins properly before repurposing it for another bulk product. To stay gluten-free:

  • Avoid products in store bulk bins entirely.
  • Buy gluten-free nuts or grains in bulk or consider ordering them online from an outlet that clearly marks them "gluten-free."

Meat Counter

Some supermarkets—especially upscale, more "gourmet"-type stores—display their meats in glass-fronted, refrigerated display cases. In most cases, those display cases don't just contain plain meats, they also include gourmet items such as stuffed chicken breasts, meatloaf mixes, marinated beef kebobs, and pre-breaded fish filets. That's where gluten can creep in.

The risk is that a stray breadcrumb will make its way next door to a plain chicken breast, or that the marinade used will contain a splash of wheat-based soy sauce.

Some butcher counters are better than others in mitigating this cross-contamination risk by separating prepared items from plain items with shields and barriers. Still, you'll need to be careful. To stay gluten-free:

  • Be aware of the risk and choose your meats and fish carefully, steering clear of those that are placed next to gluten-containing items.
  • Consider buying only pre-packaged meats even if this means visiting a different grocery store.

A Word From Verywell

The gluten-free diet is complicated and carries a steep learning curve, so don't beat yourself up if you didn't know these sources of hidden gluten in the supermarket. It pays to be vigilant and to question every food on the shelves, particularly foods that are processed or packaged right there in the store.

Not all store-packaged and store-prepared foods are problematic. Cut-up fruits and vegetables, for example, are usually quite safe because they're generally packaged in the produce section, far from bread crumbs in the deli and gluten marinades in the butcher department.

When in doubt about a particular product, ask to speak to the department manager. That person should have some training in allergens and should have an understanding of the particular risks in that department.

5 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. U.S. Food & Drug Administration. Gluten-Free Labeling of Foods.

  2. Celiac Disease Foundation. Sources of Gluten.

  3. Welstead L. The Gluten-Free Diet in the 3rd Millennium: Rules, Risks and Opportunities. Diseases. 2015;3(3):136-149. doi:10.3390/diseases3030136

  4. Celiac Disease Foundation. Gluten-Free Foods.

  5. Seattle Children’s Hospital Research Foundation. Celiac Handbook.

By Jane Anderson
Jane Anderson is a medical journalist and an expert in celiac disease, gluten sensitivity, and the gluten-free diet.