The Truth About Unopened Cooked Mussels: Are They Really Unsafe to Eat?

When it comes to seafood, safety is paramount. One common belief is that unopened cooked mussels are unsafe to eat. But how much truth is there in this culinary ‘rule’? Let’s delve into the science and facts behind this widely held belief and explore whether it’s a myth or a reality.

The Culinary ‘Rule’

The culinary ‘rule’ states that if a mussel doesn’t open when cooked, it’s dead and unsafe to eat. The logic behind this is that live mussels will open when cooked, and if a mussel is dead before cooking, it could be contaminated with harmful bacteria, making it unsafe to consume.

Scientific Perspective

From a scientific perspective, this rule isn’t entirely accurate. A study conducted by the U.S. Food and Drug Administration (FDA) found that some mussels don’t open during cooking but are still safe to eat. The reason is that some mussels have stronger adductor muscles (the muscles that hold the shell closed) and may not open during the cooking process, even though they are perfectly safe to consume.

How to Determine if a Mussel is Safe to Eat

While the ‘rule’ isn’t entirely accurate, it’s still crucial to ensure that the mussels you’re about to eat are safe. Here are some tips:

  • Before cooking, discard any mussels that are open and don’t close when tapped. This is a sign that the mussel is dead and could be unsafe to eat.

  • After cooking, if a mussel hasn’t opened, try opening it manually. If it opens easily, it’s safe to eat. If it’s difficult to open, it’s best to discard it.

  • Always buy mussels from a reputable source to ensure they’ve been stored and handled correctly.


In conclusion, the culinary ‘rule’ that unopened cooked mussels are unsafe to eat isn’t entirely accurate. While it’s a good general guideline, it’s not foolproof. Some mussels may not open during cooking but are still safe to eat. The key is to handle and cook mussels properly and to always err on the side of caution when in doubt.

Remember, when it comes to food safety, it’s always better to be safe than sorry. So, if you’re unsure about a mussel, it’s best to discard it. Enjoying seafood should never come at the expense of your health.