Safe Shellfish Consumption
Shellfish are almost a perfect food, but keeping shellfish as safe and healthful as nature intended requires proper harvesting and handling.
Rhode Island waters yield delicious edible shellfish. Quahaugs, Oysters and other molluscan shellfish are available to harvest from RI waters and can be enjoyed either raw (uncooked) or cooked.
However, there are several "natural" enemies such as bacteria, bio-toxins and harmful algae that exist in RI waters that can turn perfectly edible shellfish into "BAD" shellfish if harvested from Prohibited or Closed waters; or if shellfish are not handled properly after harvesting.
Due to seasonal increases in air and water temperatures in Rhode Island coastal waters bacteria that occur naturally have the potential to cause disease in people that consume contaminated shellfish or expose open wounds to direct contact with seawater. Two of these commonly found bacteria are Vibrio vulnificus and Vibrio parahaemolyticus, which can cause gastrointestinal illness in humans. The elderly and people with weakened immune systems or chronic liver disease are especially at risk for serious life threatening illness. To learn more about these naturally occurring bacteria follow these useful links:
- RIDOH: Foodborne Illness
- CDC: Vibrio Species Causing Vibriosis
- FDA: Vibrio vulnificus Health Education Kit Fact Sheet
- DEM Shellfish Harvester's Tips for Safety And Quality
- Vibrio Control Plan: Time To Temperature Controls (RI Regulation)
Fecal Coliform bacteria are an indicator of contamination from fecal material of humans and other mammals. The presence in shellfish waters can be the result of failed septic systems, sewage treatment plant discharges, storm water runoff, agricultural practices and direct discharge from mammals and birds.
The RIDEM shellfish program routinely monitors all shellfish waters for the presence of fecal coliform bacterium and classifies those waters that are absent of elevated levels as Approved, and are therefore safe for the direct harvest and consumption of shellfish. Those waters that exhibit above standard bacteria counts (>14 CFU/100ml) are deemed to be unsafe for direct consumption and those waters are classified as Prohibited.
Some waters are intermittently impacted due to storm events and runoff, or storm related discharges from sewage treatment plants, and are approved for shellfishing only at certain times. Those waters are deemed to be Conditionally Approved, and shellfish may be safely harvested only at those times these waters are in their "OPEN" condition.
Rhode Island’s coastal waters are occasionally impacted by Harmful Algae Blooms (HAB) that have the potential to produce biotoxins that can sicken humans if they consume fish or shellfish contaminated by HAB toxins. Shellfish are filter feeders and can accumulate biotoxins produced by these microscopic harmful algae to levels that can be poisonous. Cooking does not eliminate these toxins and consumption of contaminated shellfish can cause nausea, vomiting, diarrhea, pain, and other serious health problems. Learn more about biotoxins (Paralytic Shellfish Poisoning (PSP), Harmful Algae Blooms (HAB), Red Tide, Amnesic Shellfish Poisoning (ASP), Diarrhetic Shellfish Poisoning (DSP) )
Commercial Harvesters / Aquaculture of Marine Species
The commercial harvest of wild shellfish is a business that has been ingrained in the Rhode Island culture for hundreds of years. In recent years the growth of the Aquaculture farm for the production of oysters, mussels and hard shell clams has grown to be a million dollar business.
The Rhode Island Department of Environmental Management, the Rhode Island Department of Health and the Coastal Resource Management Council are responsible for the oversight of the commercial harvest of both the wild and cultured shellfish industry.
The protection and safety of consumers by assuring the best product served is paramount to sustaining this valuable industry. Ensuring all measures are taken to protect shellfish from contamination is critical in the deliverance of a safe and delicious product. To address contamination concerns from these naturally occurring hazards, the state has adopted the following regulations applicable to aquaculture of marine species.
Aquaculture of Marine Species
RIDEM's Division of Agriculture has amended the regulations that describe the permits, licensing, and conditions under which aquaculture, specifically the harvesting of oysters, shall be conducted in Rhode Island. These amended regulations set specific temperature controls for oysters harvested from Aquaculture facilities.
To address concerns of harvesting wild stock by commercial harvesters, specifically quahaugs, a new Harvester's Education program is currently under development by RIDEM to address the need to protect the product from bacteria contamination. Successfully completing this training program will be a requirement of all commercial shell fishers prior to obtaining their license.
Eating raw shellfish is enjoyed by many Rhode Islanders. However, certain risks associated with this practice need to be considered by those who choose not to cook their seafood prior to consumption.
RIDOH recommends the following for the proper handling of shellfish for recreational diggers.
- Harvest- Dig only in waters approved for shellfishing by RIDEM and be aware of shellfish harvesting area closures.
- Transport- Keep shellfish cold, shaded and on ice. Do not transport in water but in a clean cooler with ice packs.
- Storage- Do not store in ice water or freezer. Keep away from other foods that could contaminate the shellfish; they will last for several days if they are kept properly refrigerated below 45°F.
- Cooking- Should you choose to cook rather than eat your shellfish raw, remove any dead or open animals. Live shellfish will close tightly if tapped. Give them the sniff test- do they smell fresh? Fully cooking shellfish will eliminate bacteria and reduce your risk for illness. However, it will not kill biotoxins. If you are elderly or immune compromised you should avoid eating raw or undercooked shellfish.
Buying Raw Shellfish for the Consumer
- Buy only from licensed dealers. Look for tags and labels that contain the specific information on where and who harvested this product.
- Buy only live mollusks. When a clam, oyster, mussel or scallop is alive, the shells will be closed tightly or will close if tapped lightly. Throw away clams, oysters or mussels if their shells are cracked or broken.
- Keep the product cooled below 45°F after purchase and until the shellfish is either eaten raw or thoroughly cooked and eaten.
- Discard any product that doesn't smell "right". It should smell fresh and mild– not fishy, sour or ammonia-like.