Mussels are a popular and delicious shellfish enjoyed around the world. However, like any seafood, mussels do carry some risks if they are spoiled, contaminated, or improperly handled. Eating a bad mussel can cause food poisoning or even life-threatening shellfish poisoning in rare cases.
In this article, we’ll cover what can happen if you accidentally eat a bad mussel, from mild to severe symptoms. We’ll also provide tips for avoiding bad mussels and staying safe when preparing and consuming these nutritious mollusks.
What Are Mussels?
First, a quick primer on what mussels are and how they can become unsafe to eat. Mussels are a type of bivalve shellfish that live attached to surfaces underwater. Most mussels farmed or caught for consumption are a species called blue mussels.
Mussels feed by filtering seawater, which unfortunately also means they can accumulate bacteria, toxins, and pollutants from their environment. Contaminants can also be introduced during handling, storage, transport, or preparation.
Signs a raw mussel has gone bad include:
- Cracked or damaged shells
- Gaping, broken shells that won’t close
- A foul odor
- A slimy texture or stringy mucus
- Discoloration or graying of the mussel meat
So what happens if you eat a mussel contaminated with bacteria, toxins, or pollutants? Let’s look at the possible health impacts.
Food Poisoning from Mussels
One common risk of eating tainted mussels is straightforward food poisoning. Many of the bacteria that can contaminate shellfish thrive in the warm, wet environment inside mussel shells.
Common culprits of mussel food poisoning include:
- Vibrio bacteria
- E. coli
Symptoms of mussel food poisoning usually begin 12-48 hours after eating contaminated shellfish. They include:
- Nausea and vomiting
- Severe diarrhea
- Abdominal cramps and pain
- Fever, headache, and chills
In most cases, food poisoning from mussels can be treated at home with rest, hydration, and over-the-counter medications. However, severe dehydration, high fever, blood in stool, or symptoms lasting longer than 3 days warrant medical attention.
Preventing mussel food poisoning means proper handling, cooking, and storage of mussels by both vendors and consumers. But even properly cooked mussels can cause more serious shellfish poisoning.
Shellfish Poisoning from Mussels
Beyond standard food poisoning, contaminated mussels may cause shellfish poisoning. This refers to three types of illness caused by algal blooms that produce marine toxins:
Paralytic Shellfish Poisoning
Also called red tide poisoning, this illness is caused by shellfish feeding on toxin-producing algae like Alexandrium. The toxins attack the nervous system.
Symptoms begin within hours of ingestion and include:
- Tingling and numbness in the face, arms, and legs
- Difficulty swallowing
- Headache, dizziness, and nausea
- Vomiting and diarrhea
- Muscle paralysis
- Respiratory failure in severe cases
Neurotoxic Shellfish Poisoning
This rare poisoning comes from shellfish consuming brevetoxin-producing algal blooms. It damages the nervous system and brain cells.
Symptoms are similar to paralytic poisoning but generally milder. They include:
- Numbness and tingling sensations
- Dizziness, headache, and nausea
- Vomiting, diarrhea, and abdominal pain
Diarrheic Shellfish Poisoning
This gastrointestinal illness is caused by okadaic acid and dinophysis toxins from algal organisms. Symptoms primarily involve watery diarrhea.
Other symptoms may include:
- Nausea, vomiting, and abdominal cramps
- Chills, headache, and fever
With all three shellfish poisoning varieties, severe cases can lead to neurological problems, respiratory paralysis, and even death in rare instances. Treatment requires prompt medical care and may include:
- IV fluids and electrolyte management
- Medications to control vomiting
- Intubation and breathing support
- Charcoal decontamination
Thankfully, most cases are mild to moderate and resolve with supportive treatment. But the only way to prevent shellfish poisoning is avoiding contaminated mussels altogether.
How to Avoid Eating Bad Mussels
Now that you know what’s at stake with bad mussels, here are crucial tips to stay safe:
- Purchase mussels from reputable sellers and inspect shells. Discard any with cracks or foul odors.
- Store mussels correctly at 40°F or below and use within 2 days of purchase. Don’t freeze previously frozen mussels.
- When cooking, discard any mussels with cracked shells that won’t close and empty, damaged meat.
- Cook mussels thoroughly until the shells fully open. Boil, steam, or bake at 375°F for 5 minutes.
- Avoid raw or undercooked mussels, which may still harbor bacteria.
- When dining out, only order mussels from restaurants with high food handling standards.
- Pay attention to shellfish advisories and avoid harvesting recreational mussels during warned red tides or algal blooms.
While most farmed or commercially caught mussels are safe, it’s smart to take precautions. Careful selection, storage, preparation, and cooking of mussels significantly lowers your risk.
Staying Safe When Enjoying Mussels
Mussels can be a fabulous healthy protein source when properly handled. Just use common sense when buying, storing, and preparing mussels at home or ordering them out.
Seeking high quality, fresh mussels and cooking thoroughly to FDA recommendations minimizes your risk of food poisoning or other illness. Discard any mussels that appear off before cooking.
If you do develop concerning symptoms after eating mussels, call your doctor immediately. Prompt medical treatment can mitigate the severity of shellfish poisoning.
With reasonable care taken to source, store, and cook mussels, they can be enjoyed as a delicious and nutritious shellfish option. Just stay alert for signs of spoilage, and take health warnings related to harvesting areas seriously. By following these tips for safe consumption, you can keep mussels on the menu worry-free.