Plain mozzarella cheese is naturally gluten-free. It’s made from just a handful of ingredients: milk, rennet (an enzyme that curdles milk), citric acid, and salt. None of these contain wheat, barley, or rye, the grains that produce gluten. That said, not every mozzarella product on store shelves is identical, and a few forms of mozzarella deserve a closer look.
Why Mozzarella Is Naturally Gluten-Free
Traditional mozzarella starts with milk, which is heated with citric acid and rennet to separate it into curds and whey. The curds are then stretched and shaped into the soft, elastic cheese you know. Every ingredient in this process is naturally free of gluten. This applies to fresh mozzarella (the kind packed in water or brine), low-moisture mozzarella (the firmer block or sliced variety), and buffalo mozzarella.
Cheese in general is a safe category for people avoiding gluten. The basic cheesemaking process, coagulating milk proteins and pressing or stretching them into shape, doesn’t involve any grain-based ingredients.
Shredded and Pre-Packaged Varieties
Pre-shredded mozzarella is where things get slightly more complicated. Manufacturers coat the shreds with anti-caking agents to keep them from clumping in the bag. Common agents include potato starch, tapioca starch, and powdered cellulose, all of which are gluten-free. Wheat starch is rarely used for this purpose, but it’s not impossible.
The practical move is to check the ingredient list. If you see potato starch, corn starch, tapioca starch, or cellulose listed as the anti-caking agent, you’re fine. If wheat starch appears, or if the label lists a vague term like “modified food starch” without specifying the source, it’s worth choosing a different brand. Most major shredded mozzarella brands in the U.S. use potato or cellulose-based coatings, so this is rarely an issue in practice.
Flavored and Specialty Mozzarella
Flavored mozzarella products, like smoked mozzarella, marinated mozzarella balls, or mozzarella sticks, carry more risk. Marinades and seasoning blends can contain soy sauce (which typically includes wheat) or other gluten-containing flavorings. Breaded mozzarella sticks are obviously not gluten-free unless specifically labeled as such, since the coating is wheat-based.
String cheese, which is almost always made from mozzarella, follows the same rules as plain mozzarella and is typically gluten-free. Still worth a quick label check for any unusual additives, but standard string cheese from major brands contains only milk, cultures, salt, and enzymes.
What “Gluten-Free” Means on a Cheese Label
The FDA defines “gluten-free” as containing fewer than 20 parts per million of gluten. This threshold applies to all foods carrying the claim, including cheese. In 2020, the FDA issued a specific rule covering fermented foods like cheese, confirming that the same under-20-ppm standard applies. The label is voluntary, so a cheese that doesn’t say “gluten-free” on the package isn’t necessarily unsafe. It may simply mean the manufacturer hasn’t gone through the process of certifying the claim.
If you have celiac disease or a serious gluten sensitivity, choosing products that carry the gluten-free label gives you the extra assurance that the manufacturer has verified compliance. For plain, unflavored mozzarella from a reputable brand, the risk of gluten contamination is extremely low even without the label.
Cross-Contamination in Restaurants
The cheese itself isn’t the concern when you’re eating out. The risk comes from shared surfaces and equipment. Pizza dough flour on a prep station, pasta water, or a fryer that handles both mozzarella sticks and breaded items can all introduce gluten. If you’re ordering a dish with melted mozzarella at a restaurant, the question to ask isn’t whether the cheese is safe. It’s whether the kitchen handles gluten-free orders on separate surfaces.
Pizzerias are a common concern since flour dust is airborne and settles on everything. Even if you order a gluten-free crust, the mozzarella may have been stored or handled near wheat flour. Dedicated gluten-free restaurants or those with strict protocols are the most reliable option for anyone who reacts to trace amounts.