Cultured and pasteurized are two different processes, and one doesn’t guarantee the other. Culturing means adding live bacteria to milk to develop flavor and form curds. Pasteurization means heating milk to at least 161°F for 15 seconds (or 145°F for 30 minutes) to kill harmful bacteria. A cheese can be cultured and pasteurized, cultured and unpasteurized, or both. Most cheese sold in American grocery stores is made from pasteurized milk, but the word “cultured” on a label tells you nothing about whether pasteurization happened.
What Culturing Actually Does
Culturing is the step that turns milk into cheese. Cheesemakers add specific strains of lactic acid bacteria to milk, and those bacteria consume lactose and produce lactic acid. This acid lowers the pH, causes the milk proteins to coagulate into curds, and develops the cheese’s characteristic flavor. Without culturing (or an acid substitute like vinegar), you don’t get cheese.
The bacteria used in culturing also provide some natural protection against harmful pathogens. Lactic acid bacteria produce antimicrobial compounds, including lactic acid itself, hydrogen peroxide, and substances called bacteriocins. Research published in the Brazilian Journal of Microbiology found that as little as 0.3% lactic acid concentration was enough to inhibit the growth of Listeria monocytogenes, a dangerous foodborne pathogen. But this protection is partial. It reduces risk rather than eliminating it, which is why pasteurization remains the primary safety step.
How Pasteurization Fits In
Pasteurization happens before culturing. The milk is heated to kill pathogenic bacteria and more than 90% of spoilage organisms, then cooled down before the cheesemaker adds starter cultures. Federal regulations define several acceptable time and temperature combinations: 145°F for 30 minutes, 161°F for 15 seconds, or ultra-high temperatures like 191°F for one second. For milk with 10% fat or more, the required temperature increases by 5°F.
The key point: pasteurization targets the dangerous bacteria already in the milk. Culturing then introduces beneficial bacteria on purpose. These are sequential, complementary steps, not interchangeable ones.
When Cultured Cheese Is Not Pasteurized
Many of the world’s most celebrated cheeses are cultured from raw (unpasteurized) milk. Parmigiano-Reggiano, Gruyère, Roquefort, traditional English cheddar, Morbier, raclette, Fontina, Asiago, and many pecorinos and manchegos are all raw milk cheeses by tradition. Some cheeses, like camembert, exist in both raw and pasteurized versions depending on where they’re made.
In the United States, the FDA permits the sale of raw milk cheese as long as it has been aged at a temperature of at least 35°F for a minimum of 60 days. The aging period was originally assumed to reduce pathogen levels to safe numbers. However, more recent FDA and Health Canada risk assessments have raised questions about this assumption. Research has shown that E. coli O157:H7 can survive the full 60-day aging period in hard cheeses like cheddar. For soft-ripened cheeses, the 60-day rule may actually increase risk: Listeria monocytogenes can multiply rather than decrease as soft cheese ages. The EU applies the same 60-day aging rule for raw milk cheese exports.
The safety gap between pasteurized and unpasteurized cheese is significant. CDC estimates suggest that a person is 50 to 160 times more likely to contract listeriosis from certain soft cheeses made with unpasteurized milk compared to pasteurized versions.
How to Tell What You’re Buying
Federal labeling regulations require that all words in a cheese’s standard name, including “pasteurized,” receive equal prominence on the package. If a cheese is made from pasteurized milk, the label will typically say so. If you see only “cultured” without any mention of pasteurization, that’s not confirmation either way, but it’s worth checking the ingredient list for “pasteurized milk” or “raw milk.”
For specific cheese varieties like cheddar, Colby, and brick cheese, the federal standards of identity spell out the rules clearly: if the dairy ingredients are not pasteurized, the cheese must be aged at least 60 days at 35°F or above. If the cheese is made from pasteurized milk, no minimum aging period is required. So a “mild cheddar” aged only a few weeks is almost certainly pasteurized, while a traditionally made aged cheese imported from Europe may not be.
Who Needs to Pay Attention
For most healthy adults, both pasteurized and properly aged raw milk cheeses are considered safe. The distinction matters most for pregnant people, young children, older adults, and anyone with a weakened immune system. These groups face higher risk from Listeria and other pathogens that can persist in unpasteurized dairy. If you fall into one of these categories, look for the word “pasteurized” on the label rather than relying on “cultured” as a safety indicator.
Hard, aged cheeses made from raw milk (like Parmigiano-Reggiano) carry lower risk than soft, young raw milk cheeses because their low moisture and high salt content create a less hospitable environment for bacteria. Soft-ripened raw milk cheeses, including some brie and camembert styles, pose the greatest concern.