Pasteurized cheese is any cheese made from milk that has been heated to a specific temperature to kill harmful bacteria before the cheesemaking process begins. The vast majority of cheese sold in American grocery stores is pasteurized. If a package of cheddar, mozzarella, or Swiss doesn’t say “raw milk” on the label, the milk was almost certainly pasteurized first.
How Milk Gets Pasteurized
Pasteurization is a heat treatment first developed by Louis Pasteur in 1864. For cheesemaking, two methods are most common. High-temperature short-time (HTST) pasteurization heats milk to 72°C (about 161°F) for 15 to 20 seconds. The older method, vat pasteurization, holds milk at a lower temperature of 65°C (149°F) for a full 30 minutes. Both accomplish the same goal: destroying dangerous bacteria while keeping the milk suitable for cheese production.
After pasteurization, cheesemakers add starter cultures (specific bacteria that ferment lactose and develop flavor), along with rennet to coagulate the milk into curds. The process from that point forward, including pressing, salting, and aging, varies by cheese style. The key distinction is simply whether the milk was heat-treated before those steps began.
What Pasteurization Eliminates
Raw milk can carry Salmonella, E. coli, Listeria, and Campylobacter, all of which cause foodborne illness. Pasteurization kills these pathogens along with the organisms responsible for tuberculosis, typhoid fever, brucellosis, and Q fever. HTST pasteurization specifically destroys Coxiella burnetii, considered the most heat-resistant pathogen found in raw milk. Once the milk is clean, the cheesemaker reintroduces only the specific bacterial cultures needed to make the cheese.
How It Differs From Raw Milk Cheese
Raw milk cheese skips this heating step entirely, relying instead on aging and careful production to manage bacterial risk. In the United States, the FDA requires that any cheese made from unpasteurized milk be aged for at least 60 days at a minimum of 35°F before it can be sold. The aging period was originally assumed to reduce pathogen levels to safe thresholds, though the FDA has acknowledged that some pathogens can survive the full 60-day process.
Many of the world’s most celebrated cheeses are traditionally made with raw milk: Parmigiano-Reggiano, Gruyère, Roquefort, Raclette, Fontina, and most traditional English cheddars. When you buy domestic versions of cheeses like camembert or brie in the U.S., they’re typically made from pasteurized milk unless the label specifically states otherwise, because soft raw-milk cheeses can’t meet the 60-day aging rule.
Nutrition: Pasteurized vs. Raw
One common claim is that pasteurization strips away nutrients. The research doesn’t support this. Calcium, the most nutritionally significant mineral in milk, has the same concentration and bioavailability whether the milk is raw or pasteurized. The same holds true for zinc and selenium. Fat-soluble vitamins (A, D, E, and K) and most water-soluble B vitamins survive pasteurization with minimal losses. Pasteurization also has little impact on casein, the primary protein in cheese, and causes only limited changes to whey proteins.
In practical terms, a slice of pasteurized cheddar and a slice of raw-milk cheddar of the same age and fat content deliver essentially the same nutritional profile.
Flavor Differences
Where raw and pasteurized cheese do diverge is in flavor complexity. Raw milk contains a diverse population of native bacteria and enzymes that contribute to more nuanced, terroir-driven flavors during aging. Pasteurization wipes out that native microbial community, so the flavor of pasteurized cheese depends almost entirely on the starter cultures the cheesemaker adds back in and the aging process that follows. Neither approach is better or worse, but raw-milk cheeses tend to taste more variable and complex, while pasteurized versions are more consistent from batch to batch.
How to Tell What You’re Buying
Federal regulations require cheese labels to clearly state pasteurization status. If a cheese is labeled “pasteurized process cheese,” “pasteurized blended cheese,” or simply made from pasteurized milk, that information must appear on the package with all words given equal prominence. Manufacturers can’t make the word “cheese” large and shrink the word “process” into fine print.
You’ll encounter a few distinct categories on labels:
- Pasteurized cheese: Standard cheese made from pasteurized milk. Most cheddar, mozzarella, Swiss, Colby, and Monterey Jack sold in the U.S. falls here.
- Pasteurized process cheese: A blend of one or more cheeses that has been melted and combined with emulsifiers for a smooth, uniform texture. American cheese singles are the classic example.
- Raw milk cheese: Will say “raw milk” or “unpasteurized” on the label. If it’s sold in the U.S. and it’s a firm or semi-firm cheese, it has been aged at least 60 days.
Who Should Stick With Pasteurized
For most healthy adults, both pasteurized and raw-milk cheeses are safe to eat. But the CDC specifically recommends pasteurized cheese for pregnant women, who face a heightened risk from Listeria infection. Their safer choices include hard cheeses like cheddar, Parmesan, Swiss, and Asiago made from pasteurized milk, along with pasteurized cottage cheese, cream cheese, feta, mozzarella, and string cheese. Soft cheeses like queso fresco, brie, and blue cheese made from raw milk carry the highest risk. Young children, older adults, and people with weakened immune systems face similar concerns.