Does Milk Get Moldy And Is It Safe To Drink?

Dairy products are prone to bacteria and mold growth, with milk being no exception. It’s incredibly frustrating to go to your refrigerator to take out the milk, only to find that it has gone off and become moldy.

So, in this situation what can you do? Can moldy milk be saved, why did it go moldy so quickly and how can you stop it from happening again?

In this article, we will cover all these questions and more, so, for all you need to know about mold on milk, keep reading!

moldy milk

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Can milk grow mold?

Mold can indeed grow in liquid milk, as spores and bacteria present within the air in the tanks the milk is stored in can continue to live within the liquid. The rate at which this mold grows slows down as the milk is refrigerated and packaged.

Visible mold is more likely to grow on milk that has begun to spoil, and you will be able to identify this by changes in its texture, smell, and taste. Spoiled milk will become sour in taste, have a lumpy texture, and begin to have a slight smell of sourness to it. Only after this point is it likely that you could begin to see mold forming.

What kinds of mold grow on milk?

The most common strains of mold found growing on milk and milk-based products are Penicillium, Aspergillus, and Mucor genera.

Penicillium is found growing in not only milk but butter and yogurt products. And is frequently found growing on decaying vegetation, within soil, and on fresh fruit and vegetables.

Mucor genera is a rapidly growing strain commonly seen growing in soil, digestive systems, plants, and rotten vegetable matter.

Aspergillus is a very common mold, found growing in soil, on decaying vegetation, and grains. Pasteurization of milk will kill the majority of mold and bacteria, however, there is a risk of airborne molds finding their way into the milk during the bottling and packaging stages due to cross-contamination.

Is mold on milk dangerous?

The strains of mold found growing in milk do have the ability to cause stomach upset and allergic reactions in those sensitive to them. However, the amount of mold that you would be ingesting or inhaling would be very little. This makes the chances of any serious harm coming from drinking mold in milk quite unlikely.

Should you accidentally eat or drink mold growing in a container of milk, you would only need to seek medical advice if you had an allergic reaction or medical symptoms, if no symptoms were present, you should be ok.

What causes milk to grow mold?

Mold can and will grow anywhere if the circumstances are correct for it, all it needs is moisture, a source of nutrients, and an optimal temperature range.

Milk has a high water content and provides all the nutrients mold needs to survive. Storing milk incorrectly and at too high of a temperature can also create the ideal circumstances for rapid growth. The mold that is sometimes found living within liquid milk rarely grows at any noticeable rate as long as it is stored below 40 degrees Fahrenheit.

What does moldy milk look like?

Mold on milk and dairy products will often grow in blue-green circular patches and will have a powdery texture. If you spot the mold growing early enough, it may have a white appearance that turns more blue over time.

Should Mucor mold have developed, the growth would initially appear white and have a fluffy texture, with this turning more yellow over time.

Milk would have usually spoiled before becoming moldy, so it will also have begun to thicken and become lumpy, with splits and cracks on its surface.

How to prevent milk from growing mold

The best way to prevent mold growth on milk and milk-based products is to make sure you are storing them correctly.

Milk products should be kept refrigerated at 40 degrees Fahrenheit, and if possible towards the back of the fridge where there is less change in temperature.

Milk cartons are often kept on the shelves located at the door of the fridge, but this exposes them to frequent changes in temperature, which can allow the milk to spoil at a faster rate. So, if possible, keep the milk towards the back of the fridge and nearer the bottom shelves where the temperature is more consistent.

Also, pay close attention to the “use-by” date on the milk container, if you don’t think you will be able to use the product before the date stated, consider buying a smaller carton or looking for one with a longer shelf-life. Once you go past the date specified, spoilage and mold formation will begin.

What to do if you accidentally drink moldy milk?

Drinking milk that you later find to contain mold is unlikely to cause any major issues as long as you are not allergic to the strain of mold growing and you do not have a suppressed immune system.

If you begin to experience symptoms shortly after consuming the milk, it is best to contact a medical professional. In most circumstances, mold will only grow in any substantial way in milk that has already begun to spoil, so you would quickly notice if the milk was not fit to be consumed.


Can you still use moldy milk?

No, milk that has spoiled to the point where mold can begin to grow cannot be saved or utilized in any way. Once the milk is spoiled, the taste and texture will break down to the point where it becomes very unpleasant, so it should be discarded as soon as this is noticed.

How long does it take for milk to go moldy?

Under the correct circumstances, milk can begin to spoil and grow mold in only a few hours. As soon as the temperature of the milk goes beyond 40 degrees Fahrenheit, signs of spoilage can be seen. After a day or two, visible signs of mold growth such as patches of white, green, or blue mold will become apparent.

What is the pink mold that grows in milk?

The pink mold that is sometimes seen growing in milk and other dairy products is not actually mold but is in fact a bacteria known as Serratia marcescens.

This strain can be found growing in any moist conditions, and so favors soil and water, but can also be found on dairy products and vegetable produce.

The bacteria can cause several unpleasant symptoms if ingested, so should any signs of growth be noticed, the product it was found growing on should be thrown away.

What is the orange fungus in milk?

There are many strains of mold that can become orange in color, but the most commonly found growing on dairy products is Aleuria Aurantia.

This strain has an orange color, but its most noticeable characteristic is its texture which resembles an orange peel.

This strain has been said to be less dangerous than others with a similar color, however, bacteria are commonly seen growing alongside Aleuria Aurantia which can cause health complaints, so if it is noticed, the product should certainly be discarded.


Milk like other dairy products can indeed grow mold, but this usually occurs after the milk has already spoiled. The most common strains of mold found growing on milk and dairy products are penicillium and Mucor genera. These strains can cause stomach upset and allergic reactions in those sensitive to them, so any products found with mold growing on them should be discarded.

Chris Walker

Chris Walker has struggled for several years with mold after buying his own property. After finding the solutions to several issues around his home, he decided to create this site in order to answer as many questions about mold and mildew as possible to help others dealing with the same problems.

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