Mold In Yogurt: Is It Safe To Eat And How To Prevent It

Yogurt along with many other dairy products is prone to growing mold at a rapid rate under the correct circumstances, and it can be very frustrating to take out a pot of yogurt for a snack or to use as an ingredient, only to find green and blue patches of fluffy mold growing on it.

In this circumstance, what do you do? Can the yogurt still be eaten? And what do you do if you’ve accidentally eaten moldy yogurt?

If mold is found growing on yogurt, the item should be discarded. Ingesting the mold could cause symptoms in those susceptible to it, such as people with suppressed immune systems. The taste and texture of the yogurt will also be very unpleasant due to enzymes released by mold leading to spoilage.

In this article, we answer these questions and more, so for everything you need to know about mold growth in yogurt, keep reading!

Contents show

Can you eat moldy yogurt?

Yogurt found with mold growing on it should be discarded. Some strains of mold can produce a toxic substance called mycotoxins that can cause allergic reactions in some, and other unpleasant health conditions if the mold or its spores or inhaled or ingested.

It is not safe to scrape the visible mold off the top of the yogurt and consume the rest, as mold has roots that can go deep within the remaining yogurt that are not visible to the naked eye.

There would also be little point in removing the top layer, as once mold has begun to grow, it secretes enzymes that break down the food item is it growing on, increasing the rate of spoilage and tarnishing both the taste and texture of the yogurt.

What happens if you accidentally eat moldy yogurt?

In most cases, very little. Most people will have few (if any) symptoms after eating a small amount of mold from yogurt.

People with allergic asthma or suppressed immune systems would be more likely to suffer from symptoms after ingesting mold, but for the majority, very few symptoms would be noticed.

If after ingesting mold you begin to feel symptoms, you should seek medical advice, but if there are no obvious symptoms, you can monitor yourself over the next few days and seek advice if required.

What does moldy yogurt taste like?

Mold in yogurt has often been described as having a gritty texture and a taste similar to dirt, with a musty, or slightly bitter taste. Its smell is often compared to that of a basement or old attic, which would also come through in its taste.

Different types of mold can create different flavours, and some of these strains are used in the formation of cheeses, however, unintentional mold will often be highly unpleasant to eat. Its presence will be almost immediately obvious, due to the yogurt’s change in texture and bitter taste.

Can you scrape off the moldy yogurt and eat the rest?

No, while many people consider this a safe practice, this is not the case. Removing the affected parts of the yogurt may give the appearance that is perfectly safe to eat, but much of the mold growing would be invisible to the naked eye.

While fungi are growing, they produce thread-like roots called hyphae that burrow down into the surface it is growing on/in to act as an anchor and also to absorb nutrients. These roots can spread mycotoxins deep within the food (the yogurt in this case), meaning that the harmful compound would be spread throughout the container.

The other factor to consider here is that mold is more commonly found growing on food that has either already spoiled or is just starting to, meaning the yogurt you would be considering scraping the mold from is already way past its best and would have a terrible texture and flavor. It could even have harmful amounts of bacteria that could cause food poisoning, so scraping the mold off is not safe.

What if the mold is on the lid?

In the instance that you open a pot or container of yogurt and find there is mold growing on only the lid and there appears to be no growth on the actual yogurt itself, you may think that it is fine to eat, but once again, this is not the case.

Mold growth indicates that somewhere during the production, transportation or sales process, the yogurt was stored incorrectly, or had a defect in its container that led to the growth. It could have been kept at an incorrect temperature or could have cracks in the pot that allowed spores and potentially bacteria onto the food item.

Either way, the yogurt is no longer safe for consumption, as high levels of invisible bacteria could be present within the yogurt along with the mold, there is also the possibility that the fungi on the lid could have produced spores that have settled on the surface of the yogurt which cannot be seen.

What does mold in yogurt look like?

One of the most simple methods to determine whether yogurt has become moldy is to inspect it visually.

Mold on yogurt appears as blue-green patches of circular growth, often with a powdery texture that sits on the surface.

This will only be what is visible to the naked eye, however, as mold can have deep roots that run through the rest of the yogurt. This is the reason surface mold should not be scraped off and the remaining yogurt consumed, as you could be ingesting large amounts of mold by doing so.

If no visible mold is present, a simple sniff test can also be useful. Mold has a distinct musty scent to it, and upon opening a yogurt, if this musty scent is smelt, mold has likely begun to form. As a general rule, if any unusual smells are noticed upon opening a pot of yogurt, it should always be discarded.

If you’d like to see exactly what yogurt going moldy looks like, take a look at this time-lapse of it happening.

Why do yogurts become moldy?

Improper storage is the number one reason for yogurt becoming moldy. Storing yogurt at a temperature higher than 40 degrees Fahrenheit can allow mold and bacteria to begin growing very quickly.

Molds and bacteria can still grow at temperatures lower than 40 degrees Fahrenheit of course, but this is less common, and if stored at temperatures between 60-80 Fahrenheit for even a short period, mold can begin to grow at its most rapid rate.

Opened containers of yogurt will also spoil much faster than sealed, as cutting off the air supply removes the chances of any spores or bacteria being able to find their way into the food via cross-contamination or otherwise.

It is possible that you could open up a pot of store-bought yogurt to find it already moldy, even if you have stored it correctly. In this instance, mold spores and bacteria had likely found their way into the milk they were used before the fermentation process had begun.

If making your yogurt at home, ensure the finished product is stored in an air-tight container and consumed within 7 days. Commercially produced yogurts increase the shelf-life of the product by introducing food cultures and additives to inhibit the growth of bacteria and molds, without these components available at home, your yogurt is prone to growing mold more quickly once stored.

What kind of mold grows on yogurts?

The most common strain of mold to grow on yogurt and other dairy products, is Penicillium, a type of fungi that is commonly found growing on many food items.

Whereas some strains of Penicillium are used to enhance flavors and produce certain types of food, such as Penicillium roqueforti (used in the production of Roquefort cheese), the strains found growing in your yogurt do not make for good eating, they can spoil the taste and texture of the yogurt, as well as cause unpleasant symptoms after being consumed.

Another mold that can be found growing in yogurts and some other dairy products is Mucor circinelloides. This strain is most often found growing within soil, dung, and root vegetables, but can make its way into the milk used for yogurt production.

Mucor fungi can be identified by its slightly off-yellow coloration and fluffy texture. It often starts white and turns more yellow as it matures.

Additionally, Rhizopus strains are commonly found growing on food items, including dairy products. It is most commonly seen growing in fuzzy white patches. It is not considered a highly dangerous mold, however, it still indicates the food has spoiled and should not be consumed.

What is the white fuzz on yogurt?

Two common strains of mold have a white fuzzy appearance, penicillium, and Mucor. Penicillium growth starts its life with a white color and powdery texture, gradually changing to a blue-green hue.

Mucor also begins white and fluffy but turns more yellow over time, so it could be either of these strains. Without the use of a home mold testing kit, it would be very difficult to determine for certain which strain you dealing with.

What is the pink mold on Greek yogurt?

Despite often being called pink mold, Serratia marcescens, is a strain of bacteria that feeds off fat within yogurt and other dairy products. The bacteria usually finds its way into the milk the yogurt is made with via cross-contamination, or from within the air around the tanks that held the milk.

The bacteria can be hazardous to human and animal health, so if it is discovered growing on yogurt or any other dairy product, it should be discarded.

What about black mold on yogurt?

Several strains of mold can grow with either very dark or black coloration that may also grow on food items, these include, Stachybotrys chartarum, Cladosporium, or Alternaria. While people are most often concerned with true black mold (Stachybotrys chartarum), eating any of these strains is not recommended, as all have the potential to cause allergic symptoms in those sensitive to them.

There is also the very real possibility of gastrointestinal discomfort that could arise from eating spoiled yogurt with mold, so should this be seen in any formation, it should be discarded.

Are the molds dangerous?

Both Penicillium and Mucor circinelloides can cause symptoms if ingested, or the spores inhaled, however, this is rare and mostly affects people with suppressed immune systems or people who are allergic to mold strains.

For people with such allergies, symptoms can present as:

Headaches
Breathing difficulties

Nausea
Sneezing
Watery eyes

Itching (skin irritation)

In otherwise healthy individuals, it is possible that ingestion of either penicillium or Mucor circinelloides could cause stomach upset, gastrointestinal discomfort, and vomiting. It’s more likely, however, that the taste of the yogurt would be spoiled, rather than any serious health complaints occur.

Can you get food poisoning from moldy yogurt?

Seeing mold growing on any food item is a sign of spoilage, and bacteria that cannot be seen with the naked eye could also be producing very large colonies on the yogurt without you knowing.

A combination of bacterial growth can cause vomiting, gastrointestinal discomfort, and diarrhea if consumed. Even molds that have not produced mycotoxins can cause severely unpleasant symptoms if ingested.

How long does it take for a yogurt to go moldy?

Mold can begin to grow in an opened container of yogurt within only a few hours If left unrefrigerated and out in the open.

The higher the temperature the yogurt is left in, the faster mold and strains of bacteria will begin to grow on its surface. The mold and bacteria will be invisible to the naked eye at this point, but within one to two days, visible patches of mold will begin to appear.

If stored in the refrigerator at 40 degrees Fahrenheit or lower, mold will grow much more slowly, and the yogurt should remain edible for several days or up to one week.

Once opened, most types of yogurt are safe to consume for up to one week, with the products remaining at their best when consumed no more than 3 days after opening, and still within their “use by” date listed on the container.

Why did your homemade yogurt become moldy?

Homemade yogurt will spoil faster and be more prone to mold growth than store-bought, as food manufacturers often add preservatives as well as additional, specific live cultures that help to slow mold growth.

Store-bought yogurt comes in packaging that have had gas added to it which further prohibits the growth of molds and bacteria, extending the product’s shelf life. Without these preservation methods available, homemade yogurt will spoil and become moldy much more quickly than store-bought.

Can you bake with moldy yogurt?

You may be aware that the cooking process kills the vast majority of bacteria (this is one of the many reasons we cook foods). However, if fungi have been growing on your yogurt for long enough, they may have produced mycotoxins and released these. Mycotoxins are very resistant to heat, and while using yogurt in baking may kill the bacteria and some of the mold, the mycotoxins could still be undamaged.

Were you to eat any baked goods that had mycotoxins in them, you could still suffer from unpleasant symptoms, especially if you were allergic to them.

The yogurt will also be spoiled by the time that mold has begun to grow, so eating any foods that had been made with it would have a sour or bitter taste and unpleasant smell, so fresh yogurt should always be used instead.

How to prevent mold on yogurt

To keep yogurt for longer and prevent mold growth, keep it in an airtight container and store it in the refrigerator under 40 degrees Fahrenheit.

If possible, store the yogurt on the lower shelves of the fridge, as these tend to have a more consistent temperature. Yogurt is sensitive to temperature changes, and even small differences can lead to rapid spoiling.

It’s also a good idea to put it towards the back of the fridge, as this keeps it away from the door area where it is warmest, and more susceptible to temperature variations.

Can moldy yogurt be saved?

No, once mold formation has begun, the yogurt is already spoiled and cannot be saved. There are no effective processes you can use to remove the mold from the yogurt, so it should be discarded and fresh yogurt used instead.

Conclusion

Mold can grow quickly on yogurt if not stored correctly and at the right temperature. 40 degrees Fahrenheit or lower is best for preventing mold growth and prolonging its shelf life. If mold of any kind is found growing on yogurt, it cannot be saved and should be discarded.

Over to you

I hope this article has helped answer some of the questions you had about mold growing on yogurt, but now I’d like to turn things over to you. Have you ever eaten moldy yogurt? Do you have any extra tips on how to keep your yogurt fresh for longer, or do you have any questions about anything in this post? If you do, please leave a comment below and I’ll get back to you ASAP.