It’s a time-honored tradition on the coast: Thanksgiving dinner with oyster dressing. State environmental officials are encouraging those who partake in this seasonal ritual need to take some common sense precautions when buying, storing and preparing oysters to prevent illnesses caused by environmental bacteria. The same is true for clams.
Vibrio vulnificus and Vibrio parahaemolyticus are common, naturally occurring bacteria found in coastal waters worldwide and are most abundant when water temperatures are warm. In rare instances, these bacteria can cause serious gastrointestinal illnesses or wound infections.
During the past several years, the Centers for Disease Control and Prevention have reported an increase in Vibrio infections across the United States. People with compromised immune systems are most at risk, particularly for the more serious illnesses caused by Vibrio vulnificus. However, everyone is susceptible to less severe illness caused by pathogenic strains of Vibrio parahaemolyticus.
Before they indulge, consumers should remember these tips from the N.C. Division of Marine Fisheries’ Shellfish Sanitation and Recreational Water Quality Section:
- Thorough cooking destroys these naturally occurring Vibrio bacteria. Those with the following conditions are at higher risk for illness from raw or undercooked oysters and clams and are advised to fully cook all shellfish:
- Liver disease (from hepatitis, cirrhosis, alcoholism or cancer)
- Diabetes
- Iron overload disease (Hemochromatosis)
- Cancer (including lymphoma, leukemia, Hodgkin’s disease)
- Stomach disorders
- Any illness or treatment that weakens the immune system. If you are unsure of your risk, ask your doctor.
- Only purchase oysters and clams from reputable dealers, retailers, grocers, markets or restaurants. It is illegal for shellfish harvesters to sell directly to the public without a dealer license and certified facility. These facilities are regulated to ensure sanitation and temperature control is maintained on the shellfish.
- By law, a shellfish tag must be removed by the vendor at the last point of sale. However, you may ask to see the tag to ensure you are receiving a fresh product. For the best quality, shellfish should be consumed within 10 days of harvest. If properly refrigerated, they are still safe to eat for longer, but the quality will start to diminish.
- Keep oysters and clams refrigerated at 45 degrees Fahrenheit or below until you are ready to prepare them. The Vibrio bacteria commonly found in shellfish can multiply rapidly if left exposed to air temperatures above 50 degrees Fahrenheit.
- Thoroughly wash shellfish prior to cooking. Remove all mud and dirt from the shell using water and a stiff brush. Many dealers will wash oysters for a nominal fee when you purchase them. The mud and dirt may contain Vibrio bacteria so it is important to clean the shellfish prior to serving or cooking.
- Prior to cooking or raw consumption, discard any dead shellfish. Dead shellfish will have slightly gaping shells that will not close when tapped.
For those who harvest
Harvest of oysters by hand methods from public bottom opened at sunrise Oct. 15.
Those who hold proper commercial fishing licenses may harvest oysters from sunrise to sunset Monday through Friday each week. Commercial hand harvest limits are different for some waters, and fishermen should see Proclamation SF-5-2016 for specific hand harvest regulations.
Recreational hand harvest is allowed sunrise to sunset seven days a week. The harvest limit is one bushel of oysters per person per day or two bushels per vessel per day if more than one person is on a boat. No license is required for recreational harvest, but the oysters may not be sold.
The minimum size limit is 3-inches shell length.
Some waters may temporarily close to shellfish harvesting due to high bacteria levels associated with rainfall and stormwater runoff. Fishermen should check here for shellfish closures. Fishermen should continue to frequently check for shellfish closures throughout the year, particularly after heavy rains. They may also call the N.C. Division of Marine Fisheries at 252-726-7021 or 1-800-682-2632 to check for closures.
The season opened Nov. 14 for mechanical harvest of oysters. Those who hold the proper commercial fishing licenses should see Proclamation SF-06-2016 for more information. Mechanical harvest of oysters is not allowed without a commercial fishing license.
For more information
- About shellfish safety, contact Shannon Jenkins, the division’s Shellfish Sanitation and Recreational Water Quality section chief, at 252-808-8148 or Shannon.Jenkins@ncdenr.gov.
- About this year’s oyster season, contact Tina Moore, with the division, at 252-808-8082 or Tina.Moore@ncdenr.gov.