Why Does Cheese Grow Mold in the Refrigerator?

One of the most common reasons cheese grows mold in the refrigerator is moisture collecting on the surface, where airborne mold spores can take hold. Mold spores are present in the air and can multiply quickly on cheese when moisture and temperature are favorable. A second important factor is how the cheese is packaged: moisture trapped in an airtight plastic bag can create an ideal environment for mold.

How Do Mold Spores Get onto Cheese?

Mold spores can be present in the kitchen air, inside the refrigerator, and even on knives and cutting boards. Spores can transfer to cheese when it is cut or wrapped, then become visible within a few days in a moist environment. Moldy food stored nearby can increase airborne spores and contribute to other cheeses growing mold more quickly.

Why Do Hard and Soft Cheeses Differ?

Hard cheeses such as Kashar and aged Kashar are more resistant to mold than soft cheeses because they contain less moisture. High-moisture cheeses such as curd cheese and fresh white cheese provide a more favorable environment for mold and may grow mold within days. It is normal for soft cheeses to need to be eaten sooner, while hard cheeses can be stored for weeks without problems.

How Much Moldy Cheese Should Be Cut Away?

Mold on hard cheese is usually only on the surface; cutting away the moldy area plus at least 2.5 cm (1 inch) around and below it allows the rest to be eaten safely. Clean the knife blade if it touched the moldy part before making another cut. For soft, moist cheeses, mold roots can spread more easily into the cheese, so discard the whole cheese when visible mold is found.

How Does Packaging Affect Mold Growth?

Wrapping cheese tightly in a plastic bag can cause moisture to build up on the surface and create a nourishing environment for mold. Cheese wax paper or perforated cheese paper allows some moisture to escape and can slow mold growth. Rewrap the cheese in clean paper after each use to remove moisture and crumbs left from the previous cut.

How to Store Cheese Longer

Store cheese in the coldest, most temperature-stable part of the refrigerator, preferably in a separate container rather than the crisper drawer, to reduce temperature fluctuations and delay mold growth. A thin layer of plastic wrap over cheese paper can help maintain moisture balance without fully cutting off contact with air. Hard cheeses intended for long-term storage can be coated with a thin layer of olive oil to reduce moisture loss and direct contact with mold spores.

Rather than discarding every cheese as soon as mold appears, distinguishing by cheese type is recommended to avoid unnecessary waste. Small pieces may grow mold faster than large blocks because they have more surface area relative to their size. Buy only what you expect to eat in one sitting, or divide a large block into smaller pieces and wrap them separately to help the other cheeses in the refrigerator stay mold-free longer.