Decoding the Significance of Fishy Smelling Mushrooms

Mushrooms Smell Fishy: Causes and Significance

Mushrooms are a versatile and nutritious ingredient used in many cuisines. However, it is not uncommon to encounter mushrooms that emit a fishy odor, indicating that they have gone bad. In this article, we will explore the reasons behind the fishy smell of mushrooms and discuss its significance in determining their freshness.

Understanding Mushroom Spoilage

Mushrooms are the fruiting bodies of fungi and have a unique structure that requires special storage methods and preparation techniques. They have a fleshy texture and high moisture content, which makes them tender and juicy when cooked. However, this moisture also makes mushrooms highly susceptible to bacterial growth and spoilage.
As mushrooms begin to deteriorate, bacteria, especially harmful ones, multiply rapidly, causing spoilage. The bacteria break down the mushrooms, resulting in noticeable signs such as mold growth, rot, and the emission of unpleasant odors.

The fishy smell in mushrooms

While fresh mushrooms have a mild earthy aroma, a fishy odor indicates that they have gone bad. The fishy smell is caused by an overwhelming presence of bad bacteria on the mushrooms. It is important to note that all ingredients carry some bacteria on their surface, but when these bacteria multiply excessively, they produce noticeable signs, including the fishy odor.
In addition to a fishy odor, other signs of mushroom spoilage include mold growth, sliminess, discoloration or spots on the surface, changes in texture (such as shrinkage), and changes in color. These signs indicate that the mushrooms are no longer usable and should be discarded.

Types of mushrooms that tend to have a fishy odor

While there is limited research on which mushrooms spoil the fastest, it is generally accepted that delicate or thin mushrooms tend to spoil more quickly. These mushrooms have less flesh and moisture, making them more likely to develop a fishy odor.
For example, Enoki mushrooms, with their thin strands, can easily shrivel and give off a fishy odor. On the other hand, denser mushrooms generally have a longer shelf life due to their protective structure, which reduces moisture loss and bacterial growth.
However, it is important to note that storage conditions play a significant role in determining the rate at which mushrooms develop a fishy odor. Regardless of the type of mushroom, proper storage practices are essential to prolong its freshness.

Preventing fishy odors in mushrooms

Although mushrooms have a relatively short shelf life, there are steps you can take to prevent them from developing a fishy odor and prolong their freshness. Two key factors to consider when storing mushrooms are keeping them away from water and allowing them to breathe.
Water accelerates bacterial growth and causes mushrooms to become slimy. Therefore, it is important to avoid exposing mushrooms to excessive moisture. In addition, mushrooms need to breathe to maintain their quality. Using storage containers that allow proper airflow while remaining airtight can help achieve this balance.
Here are some practical storage tips to help extend the shelf life of your mushrooms:

  1. Buy fresh and unsliced: Choose whole mushrooms instead of sliced mushrooms. This ensures that the mushrooms are fresh and have not been exposed to excess moisture.
  2. Store in a paper bag: Place mushrooms in a paper bag, which absorbs excess moisture and prevents condensation, reducing the risk of bacterial growth.
  3. Refrigerate properly: Place the paper bag of mushrooms in the vegetable drawer of the refrigerator or in a cool, dry place. Avoid storing them in airtight plastic bags, which can trap moisture and accelerate spoilage.
  4. Use within a few days: While mushrooms can last for several days if stored properly, it is best to use them as soon as possible to ensure optimal freshness and flavor.


The fishy smell of mushrooms indicates that they have gone bad and should not be eaten. The odor is caused by an overwhelming presence of bad bacteria multiplying on the surface of the mushroom. While certain types of mushrooms may develop a fishy odor more quickly, proper storage practices are crucial to prolonging their freshness.
By following storage guidelines such as keeping mushrooms out of water, allowing them to breathe, and using fresh, unsliced mushrooms, you can minimize the risk of mushrooms developing a fishy odor and enjoy them at their best. Remember to discard any mushrooms that show signs of spoilage, including a fishy odor, mold growth, discoloration, sliminess, or changes in texture.


Why do mushrooms have a fishy smell?

The fishy smell of mushrooms is an indication that they have gone bad. It is caused by the presence of an overwhelming amount of bad bacteria on the mushrooms, which multiply and produce the unpleasant odor.

Are all mushrooms that smell fishy unsafe to eat?

Yes, any mushroom that has a fishy smell should be considered unsafe to eat. The fishy smell is a clear sign of spoilage and indicates the presence of harmful bacteria. It is best to discard such mushrooms.

Can I still use mushrooms if they have a slight fishy smell?

No, even a slight fishy smell in mushrooms is a strong indication of spoilage. It is recommended not to use mushrooms with a fishy smell, as they are no longer usable and may pose a risk to your health.

Can proper storage prevent mushrooms from smelling fishy?

While proper storage practices can help extend the freshness of mushrooms, they cannot prevent the development of a fishy odor once the mushrooms begin to spoil. It is important to follow the storage guidelines, but once the smell is present, the mushrooms should be discarded.

Are there any visual signs to look for besides the fishy smell?

Yes, in addition to the fishy smell, you may notice other signs of mushroom spoilage, such as mold growth, sliminess, discoloration, spots on the surface, changes in texture (such as shrinkage), and changes in color. These visual indicators further confirm that the mushrooms are spoiled.

Can I cook or remove the fishy smell from spoiled mushrooms?

Cooking or attempting to remove the fishy smell from spoiled mushrooms is not recommended. The smell is an indication of bacterial growth and decomposition that may have already compromised the safety and flavor of the mushrooms. It is best to discard them and use fresh mushrooms in your recipes.