Does Butter Get Moldy?

  • By: Emma
  • Date: October 10, 2022
  • Time to read: 4 min.

Is butter one of those foods that you’re never quite sure how long it’s been in the fridge? You can’t help but wonder, does butter go bad? We’ve all been there.

You see that little bit of green growing on your otherwise delicious-looking stick of butter, and you can’t help but ask yourself, does butter get moldy?

Let’s find out!

Does butter get moldy?

Yes, butter can get molds like Pénicillium. Mold needs 5-37 degrees centigrade temperature, moisture levels of up to 0.91aw, and humidity between 35-60% to grow in butter. Although butter has only 15-16% of water (insufficient for mold growth) but storage in humid places can aid mold formation. Therefore, storing the butter in low-humidity places should be a priority for avoiding molds.

Type of molds90% Humid79% Humid69% Humid
Alternaria sp0.30.60
Mucor sp000
Odium sp0.50.50.3
Penicillium roqueforti0.400
Penicillium chrysogenum0.50.30.3
Penicillium expansum0.30.30
Figure 1. Effects of humidity on the growth of Mold in butter.

Scientific evidence on whether butter gets moldy

Spoilage of butter by molds is widely reported in scientific literature. Mold spores are present everywhere in our environment. It only requires certain conditions to get into food products and spoil them.

A famous study published in the Journal of Agriculture research depicted the factors, conditions, and type of mold involved in spoiling butter.

The study conducted an experiment in which the butter was placed at various humidity levels with various salt contents. The results showed that the butter contents having more humidity levels and fewer salt contents had more formation of Pénicillium molds.

Read more: Will butter burn in cast iron skillet?

What is mold?

Mold is a type of fungus that typically grows in damp, warm environments. Mold can be found indoors and outdoors, and it can cause a variety of health problems, including respiratory infections, skin rashes, and allergic reactions.

Some types of mold can also produce toxic chemicals called mycotoxins. Inhaling or touching mold spores can cause allergic reactions in some people. Symptoms of a mold allergy include sneezing, coughing, watery eyes, and a runny nose.

How long does it take for butter to mold?

According to a study done by the National Dairy Council, it takes between three and four weeks for butter to develop mold. The study found that the rate at which mold developed depended on both the type of butter and the storage conditions.

For example, salted butter had a lower rate of mold development than unsalted butter. Butter stored at room temperature developed mold more quickly than butter that was stored in the refrigerator.

What does mold on butter look like?

Mold on butter can appear as a white, blue, or green fuzzy growth on the surface of the butter. The mold may also appear as black spots on the surface of the butter. Mold can grow on butter if it is stored in an oxygen-free environment, such as a refrigerator. Mold can also grow on butter if it is exposed to light.

Read more: Can you use margarine instead of butter for frying?

How do you keep the butter from getting moldy?

According to a study done by the University of Maine, there are a few ways to keep the butter from getting moldy.

The first is to store it in a cool, dry place. This will prevent the growth of mold spores.

The second is to wrap the butter tightly in plastic wrap or foil. This will create an airtight seal that will prevent mold spores from entering.

The third is to keep the butter refrigerated. This will slow down the growth of mold spores.

Can you scoop mold out of butter?

No, you cannot scoop mold out of butter. Butter is a dairy product that is made from cream. Mold is a type of fungus that grows in damp or humid conditions. When mold spores land on a surface, they can start to grow and form colonies.

If you see mold on the surface of butter, it means that the spores have already started to grow. Mold can also grow inside the butter, so you might not be able to see it.

Is it OK to eat moldy butter?

Moldy butter is often considered to be unsafe to eat. However, there are a few instances where it may be okay to consume moldy butter.

If the moldy butter is a different color than the rest of the butter, it should be discarded. If the moldy area is small and does not penetrate deeply into the butter, it may be safe to remove the moldy part and eat the rest of the butter.

How can you tell if butter is rancid?

When butter goes bad, it develops off-flavors that make it taste sour, bitter, soapy, or even moldy. The color can also change from the rich yellow of fresh butter to a pale or yellowish-white. The texture of rancid butter becomes harder and more crumbly than fresh butter. If you see any of these signs, it’s best to discard the butter.


So, does butter get moldy? Butter will eventually go bad and mold, but this process can take a while – up to several months in some cases. The key to prolonging the shelf life of butter is to store it properly in a cool, dark place.


Moldiness in butter

Cause and Prevention of Mold on Butter

Previous Post

Can You Eat Raw Ravioli?

Next Post

My pressure cooker is hissing (or leaking steam). 5 reasons & solutions