While not all cases of food poisoning from eating raw oysters are severe, some cases can be serious and even fatal. The best approach is to store and cook oysters properly and discard any that appear questionable.
Food poisoning from oysters is often traceable to negligence by restaurants, seafood companies, or other food handlers. If you got food poisoning after eating oysters and suspect someone else is to blame, Keep Food Safe can connect you with an experienced foodborne illness lawyer to ensure you know your full legal rights and options.
What Are the Risks of Consuming Raw Oysters?
Oysters feed by filtering water, and contaminants in coastal waters can accumulate in their tissue. Of course, most meat—even seafood—is cooked before serving, which kills many pathogens. By contrast, oysters are often served raw, which raises the risk of food poisoning.
Once bacteria, viruses, and other parasites enter the body, your immune system will attempt to purge them. This purging often occurs through diarrhea and vomiting. You may also run a high fever. People with compromised immune systems or certain diseases may be particularly vulnerable to food poisoning from raw oysters.
What Causes Food Poisoning From Oysters?
People who harvest or prepare oysters must take precautions to stop them from going bad. The Food and Drug Administration (FDA) has oyster handling regulations, which specify how they must be shucked, washed, and stored. Seafood companies or others who violate these regulations may be held liable for distributing spoiled oysters to the public.
Improper storage practices or serving oysters that should have been discarded can lead to illnesses. Contaminated surfaces and poor food handling hygiene can also cause foodborne illnesses. For instance, if a restaurant worker handles contaminated oysters without changing gloves or cleaning the work area, the contamination can spread to other food.
Commercial harvesters, restaurants, and food retailers must heed FDA advisories about contaminated waters. For example, in September 2023, the FDA issued a warning that recent oyster harvests in Connecticut came from contaminated waters, leading to a recall of the affected oysters.
Illnesses From Eating Contaminated Oysters
Consuming contaminated raw oysters can lead to several types of foodborne illnesses, including:
- Vibriosis – Caused by Vibrio bacteria commonly found in seawater and shellfish, especially from undercooked or raw seafood.
- Norovirus – Highly contagious and the leading cause of food-related illnesses in the United States, spreading through contaminated surfaces, water, and food.
- Hepatitis A – A viral infection that leads to dangerous liver infection and inflammation.
- Shigellosis – Caused by Shigella bacteria transmitted through infected food and water.
- E. coli – While often harmless and even helpful in digestion, certain strains can cause severe and potentially fatal illnesses.
Mild cases of food poisoning may resemble the flu or a stomach bug. If you or others who ate raw oysters with you become ill, notify everyone in your group. Identifying foodborne illnesses early on can help health officials issue warnings and recalls when appropriate.
Vibriosis and Oysters
Vibrio bacteria live naturally in coastal waters and can infect fish and shellfish. They thrive in warmer waters, especially during the summer months. According to the Centers for Disease Control and Prevention (CDC), there are about 80,000 cases of vibriosis annually in the United States, with 52,000 cases linked to contaminated food.
Common symptoms of vibriosis include:
- Chills
- Fever
- Nausea
- Stomach cramps
- Diarrhea
More severe vibriosis symptoms include blistering skin lesions, fever, chills, and dangerously low blood pressure. The blisters produced by serious cases of vibriosis may become infected. About 500 people are hospitalized and 100 die each year in the United States from severe cases of vibriosis.
What Happens if You Eat Bad Oysters?
How quickly you develop food poisoning symptoms from oysters depends on the contamination type. Vibriosis infections generally develop within 12 to 72 hours, while norovirus presents within 10 to 50 hours. Someone with hepatitis A may not experience symptoms for 15 to 50 days.
Symptoms of food poisoning from bad oysters may include:
- Vomiting
- Diarrhea
- Nausea
- Stomach pains
- Severe weakness
See your doctor if you suspect food poisoning from oysters or other food. Report your illness to your state’s public health department. Reporting will help identify potential foodborne illness outbreaks, which can prevent more cases through recalls and advisories.
Food Poisoning Outbreaks From Oysters
There have been numerous food poisoning outbreaks linked to contaminated oysters. Recent ones include the following:
- In December 2022, an outbreak was linked to oysters harvested in Galveston Bay in Texas. There were 10 reported cases in Texas and 37 in Florida linked to the same batch. More reports followed after a public notice.
- In January 2024, 69 people became ill after consuming raw oysters in San Diego, California. Another 150 cases were reported in Los Angeles County. The oysters originated from various locations in Mexico.
Though most food poisoning from oysters is not traced to identified outbreaks, individual cases can still originate from a contaminated batch. Even if you were the only one in a group who became ill, contaminated oysters could still be the source. A restaurant worker’s failure to discard even one contaminated oyster could lead to illness among many customers through cross-contamination.
How To Tell if an Oyster Has Gone Bad
To avoid the dangers associated with eating contaminated oysters, inspect each one closely before consuming it. Look out for these signs of oyster spoilage:
- The meat is dry, cloudy, or off-colored (gray, brown, black, or pink instead of light tan).
- There is a strong fishy odor. Fresh oysters should have a mild, briny smell like the ocean.
- The shell is significantly cracked or has a gap. Oysters should be kept alive until they are ready to be consumed, and a gap or crack likely indicates that the oyster has died.
- The shell makes a hollow sound when tapped.
The best way to protect yourself and your family is to discard any oysters you have doubts about. Taking chances is not worth the risk of oyster food poisoning.
Tips for Storing and Consuming Oysters Safely
To reduce the risk of foodborne illness from eating oysters, follow these safety tips:
- Store oysters at 40°F or below. If uncooked, serve chilled.
- Store them in an open container and maintain humidity by placing a damp (not wet) towel on top.
- Never store oysters in water.
- Ensure that each oyster’s shell is closed and undamaged before consumption.
- Don’t eat oysters if you are pregnant, have a weakened immune system, or have certain illnesses. When in doubt, consult your doctor before consuming oysters.
How Long Do Oysters Last in the Fridge?
Unfrozen seafood, especially shellfish, is best served fresh. Do not store live shellfish like oysters, mussels, clams, or scallops in the refrigerator for more than 5 to 10 days. The safest way to eat oysters is by cooking them until they are translucently white. However, they are famously and popularly served raw.
If you prefer them raw, the rule of thumb is simple: the fresher, the better. Check for food poisoning outbreaks or oyster recalls online before eating. In case of a recall, ask the restaurant or seller where they get their oysters before making a purchase.
