We use mushrooms every week. In fact, there are some weeks we almost use them every day! These tasty ingredients are incredibly versatile, so it makes sense that so many people love stocking up on them weeks in advance.
But lately, we have been getting an influx of questions surrounding the exact signs of a spoiled mushroom. And it kind of makes sense.
Many people try to use as many mushrooms as they can to prevent food wastage. But, sometimes there is nothing left to do but toss them out.
So, why do your mushrooms smell fishy? If your mushrooms start to smell fishy (and even at all), they have gone bad. There is no way of saving them or salvaging them.
In this extremely in-depth article today, we will look at how mushrooms go bad and what these signs are. This will directly help you choose the best storage methods to help extend their shelf life.
What Exactly Are Mushrooms?
Mushrooms are not only incredibly versatile ingredients, but they are also very nutritious, affordable (most of them at least), readily available, and quick to cook!
They also require minimal preparation. At the most, you have to clean and slice them (but even slicing is optional).
The way mushrooms can be cooked is what mostly makes them appealing to cuisines across the globe. Almost every cuisine out there uses mushrooms in one way or another.
Mushrooms can be steamed, boiled, deep-fried, pan-fried, roasted, braised, and grilled. If you can think of a cooking method, you can prepare mushrooms using it!
Now, you probably already know about all of these amazing qualities of mushrooms. But do you know what they are? Why is it important to know?
Well, as we always like to say, by understanding what an ingredient is and what its structure is like, you will be able to much better understand what affects it and how.
There’s no point in being able to recognize that your mushrooms are slimy if you don’t understand what went wrong in the storage process.
The Shelf Life of Mushrooms
Mushrooms are the spore-bearing fruiting bodies of the fungus. Yes, we said fungus! But most people already know that. However, what no one really ever talks about is the structure of a mushroom.
Sure, many different kinds have vastly different appearances. But, their structures are all relatively the same. And it’s this unique structure that requires very special storage methods and preparation techniques.
Mushrooms are very fleshy ingredients with a very porous texture. They also contain a ton of moisture in their flesh, which is why they can be so incredibly tender and juicy once cooked.
The high moisture content is mainly what causes mushrooms to deteriorate so quickly. The moisture acts as a food source for bacteria (specifically harmful ones in this case) and causes them to multiply.
Once they do, the living mushrooms quickly start decomposing. This process is much quicker in comparison to many other fruits and vegetables, but still not lightning fast. So, you should still have time to use any suspicious mushrooms.
Why Would Mushrooms Smell Fishy?
Regular mushrooms are relatively odorless. While they do have a slight earthiness to them, it isn’t strong at all.
So, once you start smelling a fishy aroma, your suspicions should immediately peak. And rightfully so! Any mushrooms that have a fishy smell are far past the point of no return.
This smell is caused by an overwhelming amount of bad bacteria. All ingredients do have some bacteria on their surface. Once the bacteria start multiplying too much, they start showing noticeable signs of their presence. A fishy smell is one of them.
A much more common and noticeable sign of this is mold growth or rot formation. But, unfortunately, many people ignore smell changes in their produce, which usually appear before a drastic amount of mold.
So, if you notice any smell changes within your mushrooms, rather discard them. These changes can be fishy, musky, or even sour. The worse off they are, the more pungent the smells will be. And, it is almost impossible to miss.
Which Mushroom Types Gets a Fishy Smell Quickest?
There isn’t any solid research we could find on which species of mushrooms spoil the fastest.
In our opinion, we would say the more delicate or thin mushroom types will spoil more quickly. They generally have a lot less flesh and therefore less moisture to lose. So, they will get to a fishy smell quicker.
Enoki is a great example of our theory. These long thin strands can be as thin as 1mm each. So, they will much more easily become shriveled and ultimately fishy.
Then, our second guess is that denser mushrooms will generally last longer. Again, their structure protects them better from moisture loss and therefore bacterial growth.
Now, all of this said, the factor that mostly affects how quickly mushrooms will get that awful fishy smell is how you store them. Which species of mushroom it is doesn’t even matter at the end of the day if you don’t look after them!
If you want your mushrooms to last as long as possible in your refrigerator, make sure to purchase whole mushrooms instead of pre-sliced ones as well.
Are Fishy-Smelling Mushrooms Always Bad?
Unfortunately in our experience, once your mushrooms get that fishy smell, you cannot use them. You will never find any kitchen worth their salt using and serving any type of fishy mushroom dish. So, neither should you!
As we have explained before, the fishy smell comes from an overwhelming amount of bacteria on the mushrooms.
Once the bacteria have multiplied to the point where they produce any type of smell, you will likely also notice some visible signs of deterioration (spoilage).
The mushrooms start forming spots on their surface. Then, they can even become slimy. This is often followed by them physically starting to rot, and then, of course, the fishy pungent smell.
How to Tell if Fishy Mushrooms Have Gone Bad
There are a ton of ways to tell whether or not your mushrooms have gone bad. The fishy smell (as we have already said) is an obvious giveaway that you should immediately discard the mushrooms. But, this sign often doesn’t appear first.
So, here are some other common signs that your mushrooms have either started going off or are already beyond a usable state.
Spots Appear on the Surface
This is often the first sign of mushrooms going bad. Most kinds of edible mushrooms have a relatively uniform color. At the very least, they don’t have spots.
So, if your mushrooms start showing some discoloration or spots, you should consider using them immediately. They will still be fine to use if they don’t show any other signs of being bad.
After some spots have started appearing on the mushrooms, they will soon start going slimy. But, not all mushrooms show spots before this.
Some just go slimy overnight. This is a sign that your mushrooms are very old and have been kept inside the fridge for too long.
While the slime isn’t known to be especially dangerous to eat, it isn’t appealing. And no, you cannot just rinse it off. In fact, trying that could just make it worse!
Now, this differs from spots appearing on the surface of your mushroom. The actual mushroom should also not change color. You will often find that as they deteriorate and age, they become darker as an entirety.
Ultimately, depending on the level of color change the mushrooms undergo, they may still be fine to use. But if the change is too drastic, rather toss them out. It is always better to be safe than to end up in the hospital from food poisoning.
Mushrooms should have a firm texture. Keep in mind, that firm doesn’t necessarily mean rigid. Let’s take enoki as an example again.
This tiny cluster of mushroom strands also has a firm texture but is very flexible (physically). They can bend and move in many different ways.
If your mushrooms start shriveling, it means that they have either accidentally dried out or have lost too much moisture from aging.
Depending on the severity of the moisture loss, you may still be able to use them. They can be a bit on the tougher side, but they will still be edible. However, if they are very shriveled, it is better to toss them out.
And finally, as we have mentioned, any type of odor that comes from mushrooms is an undeniable sign that the mushrooms are bad. No exceptions to this rule. Even a whiff of any type of smell is bad enough to make you sick.
How to Prevent Fishy Mushrooms
Now, you may be feeling very discouraged right now. Why even bother buying mushrooms if they go bad quickly and then cannot even be saved in some way?
Well, as easy as it is to cause mushrooms to become fishy, it is equally easy to prolong their shelf life and prevent this from happening entirely.
There are two key things to remember when storing mushrooms. These are the most important and if anything, you should implement measures for these only.
The first is to keep mushrooms away from water. Water will speed up the bacterial growth and cause the mushrooms to become almost instantly slimy!
The second is to allow the mushrooms to breathe (we love these storage containers on Amazon because they allow produce on the bottom to breathe while remaining airtight).
Below are some of our best storage tips and tricks you can use to properly store mushrooms. We can almost guarantee that they will last a lot longer!
Buy Fresh and Unsliced
This seems like a “duh” thing to say. But do you ever actually properly look at the produce you buy? Many people don’t.
You give it a quick glance to make sure there aren’t big rotting pieces or slimy bits. Beyond that, no second looks or closer inspections.
But, this is often the number one reason that peoples’ mushrooms go bad almost instantly! Your mushrooms may look good from a distance, but you should always give them a closer look.
Look for discoloration or any blemishes. These are the most obvious signs that the mushrooms are already approaching their deadline.
Store Them Inside the Fridge
Storing mushrooms at room temperature will dry them out in only a couple of hours.
It doesn’t take much at all! But, as we have said, you should keep mushrooms away from moisture. And, as you may know, fridges are packed with it!
But, it is still far better to store your mushrooms in colder areas than at room temperature. The fridge will also help delay bacterial growth that can cause slime and rot.
Store Them in the Correct Containers
Mushrooms should never be kept inside an airtight container or bag. This is why all of their packets have large holes in them.
This allows the mushrooms to breathe. It also helps prevent condensation from forming inside the container, which in turn speeds up the deterioration.
So, the best place to store mushrooms is inside their original packaging, in a brown paper bag, or some paper towel.
Many people say a plastic bag, but personally, we don’t like it. It doesn’t allow the mushrooms to breathe effectively and it can cause condensation.
What we would do with a plastic bag is line it with a paper towel. Place the mushrooms inside, and just gently close the top.
Do not tie the handles, and do not fold them closed. There should be small open spaces that will prevent condensation.
Otherwise, a brown paper bag is very porous and works well. You will even see mushroom vendors at farmers’ markets sell them this way. Not to mention, it is a far more eco-friendly method than plastic bags!
Avoid Opening the Container
If you aren’t ready to use the mushrooms yet, avoid opening them in the first place. This will help keep them in the environment the supplier recommends without any disruptions.
And, if you need to store leftover mushrooms, again, don’t re-open the packet until you are ready to use them again.
Can You Get Sick From Eating Fishy-Smelling Mushrooms?
As with all spoiled ingredients, the harmful bacteria that cause them to rot will cause you to get sick as well. And when it comes to fishy mushrooms, they can make you exceptionally sick!
Can You Dry Out Fishy Mushrooms and Still Use Them?
We do not recommend drying out and eating mushrooms that are fishy. No amount of cooking and preserving can save decomposing ingredients.
The harmful bacteria that are present have already multiplied to such an extent that the ingredients cannot be saved. The risk far outweighs the pros.
How Long Do Mushrooms Last?
Fresh mushrooms that haven’t been cut in any way can last for up to two weeks inside the fridge. But, and it’s a big one, they have to be exceptionally fresh and properly stored.
Once they have been cut, they instantly lose their freshness and start shriveling up. Cooked mushrooms can only last for a day or two.
Can You Freeze Mushrooms?
Mushrooms can be frozen at home as a way to extend their shelf life. But, only freeze them if they are still fresh. Don’t freeze nearly spoiled produce.
Then, once they have been thawed, you have to cook them over very high heat. This will help prevent their texture from becoming rubbery and the dish from being watery.