What Are The White Things On Mussel Shells?

When harvesting mussels, you may notice that some have white things on their shells. You may wonder what those white things are and if mussels with white things on them are safe to consume. We have done some research to determine what the white things on mussel shells are.

Three main reasons for white things on mussels are white worms, barnacles, and Byne’s disease. Although these white things may not look appetizing, they don’t affect the mussel meat, and the mussels are still edible. You can remove barnacles and white worms with a blunt knife or stiff brush.

Most often, the white things on mussel shells are found on wild mussels. Farmed mussels have fewer growths and are often cleaner than wild ones. We will discuss different reasons for white things on mussels, which mussels are safe to eat, and how to remove the white things on mussels.

What Causes The White Things On Mussels?

There are three main reasons for white things growing on mussels. Two occur naturally at sea, while the third results from improper storage. Fortunately, white things on mussel shells don’t often affect the mussel meat, and these mussels are therefore safe to consume. These are the three main reasons for white things growing on mussels.

1. White Worms On Mussel Shells

White worms also grow on the same rock beds are mussels do. Therefore, it’s pretty common to find white worms on mussel shells. These worms create sand tunnels, which have a white, squiggly appearance.

White worms commonly grow on the shells of wild mussels. While mussels with white worm growth don’t look as appetizing, they are perfectly safe to eat. The white worms don’t affect the mussel meat and therefore cannot cause the mussel to become inedible.

2. Barnacles On Mussel Shells

Another common cause for white things growing on mussels is barnacles. These tiny sea creatures grow on rocks, the underside of ships, and shellfish. Barnacles can occur in various colors. However, if they are left to dry in the sun, they will have a white color and look like tiny bumps on the mussel.

Barnacles can occur on wild and farmed mussels. However, they are more commonly found in wild ones. Barnacles also don’t affect the mussel meat, and it’s perfectly safe to eat mussels with barnacle growth on their shells.

3. Byne’s Disease On Mussel Shells

Byne’s disease isn’t as common as white worms or barnacles. However, this disease can also cause white spots on mussel shells. Byne’s disease results from acids being released around the mussel shells. These acids cause the shells to start breaking down. As a result, you might notice white bubbly or chalky spots on the mussel’s shell if it has Byne’s disease.

Byne’s disease occurs due to improper storage for a long time. Storing your mussels in wooden crates or plastic containers for a long time can cause Byne’s disease to develop. However, Byne’s disease doesn’t influence the mussel meat, and you can still eat the mussel if the shell hasn’t broken because of Byne’s disease.

How To Remove The White Things On Mussel Shells

Now that we have established the main reasons for white things growing on mussels, you might wonder if you can remove them? While these white things don’t make the mussels inedible, they don’t look appealing. They can spoil your appetite, especially if you plan to serve the mussels in their shells.

Removing barnacles and white worms from mussels is as easy as taking a blunt knife and scraping it off the mussel’s shell. Be gentle while doing so, however. Applying too much pressure on the shell can cause it to break and will mean you can no longer use that mussel.

Unfortunately, you cannot remove the white spots if Byne’s disease causes them. Because these white spots result from calcification and the degeneration of the shell’s structure, the white spots cannot be removed.

However, you can stop the process from progressing further by washing the mussels with clean, cold water. Byne’s disease isn’t contagious. Therefore, if you remove the mussel with Byne’s disease and place the mussels in a suitable container, such as a mesh bag, you can prevent a further outbreak of this disease.

Eventually, Byne’s disease will eat through the mussel shell, and this will cause the mussel to die. In this case, the mussel will no longer be edible. However, this takes a really long time to happen, and as long as the shell is intact, you can eat the mussels despite their shells having Byne’s disease.

When Are Mussels Unsafe To Eat?

If white things don’t cause mussels to become inedible, you might still wonder what does. How can you tell which mussels are safe to eat and which ones you should through away? Five leading indicators signify when mussels are no longer safe to eat.

Shellfish develop harmful bacteria as soon as they die and start to decompose. These bacteria can cause you to become violently ill or may even lead to your death. Therefore, it’s never worth eating questionable mussels if you suspect they may no longer be fresh. These are the signs that mussels are unsafe to eat.

1. If The Mussels Smell Bad

Fresh mussels should smell like the ocean. They should have a fresh and slightly salty scent. However, if you notice the mussels smelling fishy or rotten, you should consider those mussels unsafe to eat. These mussels have likely already died and can cause illness and death if consumed.

2. If The Mussel Shells Are Dry

Fresh mussels should be stored on ice or in a cold area. If the shells look dry and wilted, you can assume that the mussels were exposed to sunlight and are therefore unsafe to eat. The mussels will die if they are left out in the sunlight. Therefore, don’t eat any mussels with dry or faded shells.

3. If The Mussel Shells Are Broken

Another indication that the mussels are unsafe to eat is broken shells. Fresh mussels should have shiny black, blue, or green shells, and the shells should be whole. If the shells are cracked, chipped, or broken, the mussel inside is likely already dead and therefore unsafe to eat.

4. If The Mussels Are Unresponsive

Mussels often gape when they are removed from the ocean. This means that they open and close their shells while searching for water. However, if the mussel is alive, it will close its shell tightly when you tap it. If the mussel shell doesn’t close or close slowly or loosely, the mussel is dead or dying, and you shouldn’t eat it.

5. If The Mussels Are Stored Incorrectly

Mussels must be kept in a cold area before they are cooked and eaten. They should also have access to oxygen. Therefore, if you notice the mussels lying in a bowl of water or placed in an airtight container, they are no longer safe to eat. The mussels may have gotten hot or suffocated and are no longer alive or safe for consumption.

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The leading causes of white things on mussel shells are white worms and barnacles. Both these animals naturally grow on mussel shells and don’t affect the mussel meat. You can eat the mussels with barnacles or white worms on them. Before cooking the mussels, you can remove the barnacles or white worms with a blunt knife.

Byne’s disease is another cause of white things on mussel shells. Byne’s disease occurs when the mussels aren’t stored correctly, and the disease causes the shell to break down. If the mussel is still alive, you can safely consume mussels with Byne’s disease.