Mold on butter - What is the cause and what to do?

Smooth, rich, and utterly indulgent, butter is a staple for many families. There’s nothing like the taste of real butter, whether you’re using it in baking or as a generous spread on golden toasted bread slices.

But if you find mold in butter, what should you do?

The main causes of mold in butter are contamination, heat, and exposure to air. Butter that has gone moldy should not be eaten, as it may contain harmful toxins. The best way to keep butter fresh and mold-free is to keep it refrigerated in an airtight container.

Do you want to keep your butter fresh and delicious? We have all the answers and more for you! We’ll take a look at what to do with moldy butter and give you some tips on the best way to store this dairy treat.

What is butter?

Rich, smooth and flavorful – there aren’t many people who don’t enjoy the depth of flavor that butter adds to their diet!

Butter is a dairy product that has many uses and is popular as a baking ingredient. It is almost always used on sandwiches and toast, and adds a rich flavor to sauces and pans.

But what exactly is butter? If you’ve never tried making butter yourself, you may wonder what miracles go into creating this delicious block of dairy.

The basic ingredient of butter is the creamy part of the milk. Butter is normally made from cow’s milk cream, but in some countries sheep, goat, buffalo and even yak milk can be used to make butter.

How is butter made?

When you see a carton of cream in your fridge, it can be hard to imagine how it can be turned into butter. But this is where the magic happens… the emulsion!

Emulsification is the process of suspending fat in water, turning two ingredients that don’t normally mix together into a smooth mixture. In butter, the milk proteins act as emulsifiers, mixing the butterfat of the cream with the liquid part.

This is done through a process called whipping; traditionally it was made by hand, but modern methods use machines. Whipping means the cream is vigorously mixed, causing the fat globules to break and stick together. These form clumps of fat, with fluid trapped inside.

In the end, smooth lumps of butter are obtained, which float in a thin milky liquid. This liquid is called buttermilk and is a useful byproduct of butter. The buttermilk drains off and the solids transform into a firm scoop of butter.

Butter storage

Butter is quite unusual in that unlike other dairy products, its texture changes based on temperature.

When cooled, butter is a solid, and when heated it becomes a liquid. At room temperature, butter is a semi-solid, the perfect state for spreading our toast!

With dairy products, we are all used to being very cautious when it comes to storing them. Most dairy products should always be kept cold, otherwise they go bad very quickly. So why is butter so different?

It all comes down to the high fat content and low water content of the butter. This inhibits mold growth, even at room temperature. However, butter can go moldy under the right conditions.

What causes mold in butter?

Butter is a relatively stable dairy product and typically has a long shelf life. Unlike other dairy products, such as yogurt, butter doesn’t mold easily.

In fact, it can be kept in the fridge for up to three months, even after opening it! However, butter can go moldy, and there are a few reasons why this can happen.

1. Pollution

The main culprit in many homes is the use of contaminated utensils. And yes, we all know how it happens, and many of us are guilty of it!

When you’re making a batch of sandwiches for the family, it sometimes seems easier to use the same knife for everything. So you spread one round of bread, you spread the peanut butter or jelly, and then you move on to spreading the next round of bread.

And now your butter is contaminated with tiny particles of whatever you stuffed into your sandwiches - oops!

Even if you clean the knife when you change your sandwich filling, contamination will still occur. And even if you’re just buttering bread or toast, the crumbs will inevitably end up in the butter!

2. The heat

Exposure to heat greatly increases the chance of your butter going moldy. The first reason is that heat favors the growth of mold, allowing it to spread and grow more quickly.

Second, when the butter is hot, it becomes softer. This allows the mold to penetrate deeper into the butter itself.

3. Air

For mold particles to contaminate your butter, they usually travel through the air. Butter that is not kept in an airtight container has a much higher chance of molding.

The air also causes another problem: oxidation. This is a natural process by which food deteriorates when exposed to air. This makes your butter rancid and tasteless.

4. Salt

At the grocery store, you’ll see two types of butter: salted and unsalted. Salt is an excellent preservative and inhibits mold growth in butter.

Unsalted butter is much more prone to mold, especially if stored at room temperature.

How do you know if the butter has gone bad?

To check if your butter is safe to eat, you will need to do a thorough inspection of the following areas

1. Appearance

Look at the surface of the butter: can you see any fine hairs of mold developing? Extended mold will be more apparent, creating a hairy appearance in the butter.

Also check the color of the butter. Look for discoloration: Fresh butter should be a uniform, light yellow color. Any change could mean your butter has gone rancid.

2. Smells

Butter Smells Good: Does it smell sweet and milky? Milk that has become moldy will have a characteristic musty odor. Rancid butter will have a sour, unpleasant odor.

3. Test

Try butter only if it has passed the appearance and smell tests. Moldy, stale butter will be extremely unpleasant, with a sour, sour taste.

Is it safe to eat moldy butter?

Unfortunately, if you see mold on your butter, it is no longer considered safe to eat.

The US Food and Drug Administration (FDA) has classified moldy butter as unsafe for consumption. Not only do you run the risk of food poisoning and botulism, but the toxins will damage your immune system.

This is especially worrying in the case of soft butter, especially that which is stored at room temperature. The softer consistency allows the mold to penetrate deeper into the butter, spreading the toxins along the way.

Slightly moldy butter - can I cut it up and eat the rest?

So you’ve opened your butter dish and there’s a thin layer of mold in one area. What a disappointment, especially if you have an intense day of cooking planned! But can you cut off the mold and eat the rest?

The official advice from the FDA is that all moldy butter should be thrown away, as it poses a threat to human health.

However, many people will tell you that they would cut off the moldy part and eat the rest anyway, so is it safe to do so?

Obviously, we strongly advise you to stick to the FDA guidelines - these guys know their stuff when it comes to food safety!

But if you’re tempted to try and salvage your moldy butter, we want to make sure you do it in the safest way possible.

Things to keep in mind when cutting butter mold:

• Never make it with butter that has been left out at room temperature. The warmer temperatures will have softened the butter and allowed mold and toxins to penetrate deeper than you might expect. Trim only mold from butter that has been kept refrigerated or frozen.
• Take the butter out of its container or container before attempting to trim away the mold. Existing packaging should be discarded, and used containers should be thoroughly washed.
• Be generous when trimming the butter. You must leave a wide margin between the mold and the part that you are going to consume.
• Use a clean, sharp knife and a clean work surface.
• When you’re done cleaning the pan of your butter, transfer it to a clean, airtight container and store it in the fridge.
• Use the butter as soon as possible - it’s unlikely that you’ve killed all of the mold spores, and it will quickly spread through any remaining butter!

Should I worry if I’ve accidentally eaten moldy butter?

If you’ve accidentally eaten moldy butter, don’t panic! Moldy butter is highly unlikely to cause food poisoning, especially since butter is typically eaten in very small amounts.

However, eating moldy butter has its risks, which is why the FDA advises against it. Molds release toxic substances, known as mycotoxins. These can cause allergic reactions and respiratory problems.

Moldy butter is also very likely to be rancid, meaning it has completely gone bad. In addition to having an unpleasant taste, rancid butter will spoil any recipe if you try to cook with it.

Can I bake with moldy butter?

Baking with moldy butter is just as dangerous as eating it raw. This is because the baking process will kill molds in the butter, but will not remove mycotoxins.

These toxic substances will remain in the butter, even if it is heated or baked.

How to prevent mold in butter

To understand how to prevent mold in butter, we need to re-examine the causes of mold.

1. Pollution

Avoid contaminating your butter with other foods, as this is the main cause of moldy butter. Use a different butter knife, and be sure to clean it regularly. Any crumbs or contamination from your butter must be carefully removed.

2. Heat

Butter that is kept refrigerated is much less likely to mold. Keeping the butter in the fridge is the obvious solution, but this can make the butter hard and difficult to spread.

If you prefer to keep your butter at room temperature, avoid direct sunlight and the warmest areas of the kitchen.

3. Air

Butter should always be stored in an airtight container. If you use a butter dish, make sure it has a tight seal around the edges. Butter is often wrapped in paper, which is not suitable for long-term storage.

4. Salt

Salted butter is much less likely to go moldy, especially if you want to keep it at room temperature. Most people keep salted butter at room temperature for sandwiches, and unsalted butter in the fridge for baking.

Related questions

Can butter be frozen?

Freezing butter is a good way to extend the shelf life of this versatile dairy product.

Once frozen and thawed, the flavor and texture of the butter change very little. And if you didn’t already know this great cooking tip, frozen butter makes perfect pastry dough when grated into flour!

Butter must be protected from air when frozen; the best way to do this is to keep it in its original container, wrapped in an extra layer of aluminum foil or freezer paper.

You can also cut the butter into smaller portions and freeze it in an airtight container.

Salted butter can be kept for up to nine months in the freezer. Unsalted butter keeps for up to five months in the freezer.

What is the best way to soften hard butter for sandwiches?

We all know that horrible feeling when you rush to make sandwiches in the morning and realize you forgot to get the butter out of the fridge the night before.

But instead of breaking the bread into pieces with the solid butter, there are some quick and easy ways to soften the butter.

The best method of softening butter for sandwiches is to cut the amount of butter you need from the main block of butter.

Cut it into smaller pieces and mash them with a fork. Leave the pounded butter in a warm place for 5-10 minutes and it should be much easier to spread.

Alternatively, if you’re in a hurry, you can use the microwave to soften the butter. Be careful with this method, as the microwave will quickly turn even the hardest butter into a liquid.

We suggest you use a low-medium setting in 10-second bursts at a time until the butter is the desired consistency.

How do you store butter at room temperature?

Many of us keep butter at room temperature at all times, with no adverse effects. However, this is most likely because we consume a block of butter very quickly.

Food authorities advise storing at room temperature only the amount of butter that you will consume in a day or two. The rest should be stored in the refrigerator.

The best way to store butter at room temperature is in a dark container with a lid, which does not allow light or air access to the butter. Keep this container in an area with a constant room temperature, away from heat and direct sunlight.