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SafeOysters.org - Consumers

Vibrio vulnificus

Infection from Consumption of Raw
Shellfish or Marine-Related Wounds

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Safely Buying Raw Oysters and Other Molluscan Shellfish

Where should I buy oysters, clams, or mussels?

You should only purchase oysters, clams, or mussels from a reputable retail or wholesale store that has a valid business license. Seafood dealers with current licenses are inspected by state, local, and sometimes federal regulatory agencies to ensure shellfish is obtained from approved sources, maintained at proper storage temperatures, and handled in a sanitary manner and work area. If you have questions about your local seafood dealer or are uncertain about their license status, contact the government agency responsible for retail or wholesale food inspection in your state, county, or city.

Even if a seafood dealer has a current business license, a strong, unpleasant fishy odor which pervades the store often indicates inadequate sanitation or refrigeration. Be particularly thorough in your evaluation of shellfish before purchasing it from such an establishment.

What about shellfish from roadside stands or transient vendors?

If a vendor does not have a valid state or local business license to sell seafood, there is no way for government inspectors to know if shellfish is legally obtained from approved waters or safely and sanitarily handled and stored.

How do I tell if shellfish has been legally harvested?

If you are concerned about the source of raw oysters, clams, or mussels, ask to see the certified shipper’s tag or information that accompanies legally harvested live products, or find the harvester information on containers of raw shucked (shells removed) shellfish. This information ensures the shellfish was harvested from approved* waters and that the harvester, processor(s), and/or shipper(s) are certified and monitored by state and federal regulators. Molluscan shellfish without that information could be illegally harvested from polluted waters and could cause illness. The safety of such shellfish is impossible to determine and purchase or consumption should be avoided.

How do I tell if shellfish is alive?

Shells of live oysters, clams or mussels, will either be tightly closed or slightly open. If shells are open, tap them lightly with your finger. If the shell closes, the animal is alive and safe to buy. If the shell is gaping open or does not close after tapping it, the animal is dead and may harbor high numbers of bacteria which can make you ill.

Is it safe to eat previously shucked shellfish raw?

No. Shellfish that has been shucked (removed from shells) and placed in plastic or glass containers is intended to be cooked and should not be eaten raw.

Is it safe to harvest and eat my own oysters, clams, and mussels?

Most coastal states, counties, or cities provide and monitor areas for recreational public harvesting of oysters, clams, or mussels. Water and/or shellfish in these harvest areas are routinely tested * to ensure they do not contain bacteria or viruses from sewage, toxins from natural algal blooms, or other contaminants that can cause human illness. If harmful contaminants are present, the area is closed to harvesting and signs are posted to warn of the danger.

Some states may require a permit and/or licenses to recreationally harvest shellfish and/or set limits on the amount you may harvest. Check with the department or agency responsible for monitoring public harvest areas in your state, county, or city or use the links below to locate information by state.

* NOTE: Since Vibrio bacteria are naturally present in marine waters and are not a serious threat to most consumers, harvest areas are not tested for Vibrio. Therefore, it is not safe for high-risk consumers to eat raw or undercooked oysters, clams, or mussels from either commercial or recreational public harvest areas, even if the area is approved for harvesting. Thorough cooking of shellfish kills Vibrio bacteria. For more information about who is at risk for Vibrio vulnificus infection, see "Introduction to Vibrio vulnificus, What Raw Oyster Consumers Should Know."

SafeOysters.org is a gateway to Vibrio vulnificus information
for health care providers, food and health educators, consumers, fishermen 
and commercial processors.

Updated: 9/1/2009 - Send comments or questions to:web editor.