Doing it right. Fresh Oysters and Required Record keeping
Updated: May 31
Shellfish are filter feeders which mean they filter whatever is in the water – the good (food) and the bad (bacteria, viruses, etc.). If a customer eats tainted shellfish, the Oregon Department of Agriculture, in conjunction with our department, will conduct an investigation. Proper documentation of your shellfish tags is essential for an accurate and speedy resolution in determining what growing beds or areas may be tainted.
Oysters are typically grown (farmed) and harvested in our coastal waters. It is not a controlled environment and therefore these filter feeders are subject to whatever is in these waters. Other filter feeders such as clams, mussels, and crabs are subject to the same bacteria overload but are generally not eaten raw (not cooked = no heat kill step) so the incident rate is lower.
During warm months there is a bacterium that naturally multiplies more rapidly in the waters that shellfish filter and consequently collect. This greater amount of the bacteria can cause people to get sick. The symptoms are too familiar: diarrhea, abdominal cramps, nausea, vomiting, headache, fever, and chills. This bacterium is called Vibrio.
If a customer becomes ill from eating raw or under-cooked shellfish at your food service, you need to report it to our department immediately. We also learn about confirmed Vibrio, Norovirus and even Hepatitis cases from primary care doctors, who then reports to our Communicable Disease nurses. We will come to your facility and pick-up the shellfish tags and turn them over to the Oregon Department of Agriculture. These tags provide them with a starting point for tracking down the area where they were harvested. We also review your oyster handling practices. We will collect customer receipts, menus, and other documents to help track the illness outbreak.
The current outbreak investigations in our country are for Norovirus. Sometimes there are agricultural overflows when fertilizers or animal excrement flow into the coastal waters. We might also have a sewer overflow with raw sewage entering our fresh and salt water environments. Illnesses that could occur with these types of contamination include Norovirus, E. coli, and Hepatitis.
What’s required if you sell raw oysters in your facility:
As the owner/operator/chef in charge, you are required to keep all fresh shellfish tags for 90 days. It is essential that the tags stay with the live oysters until the last one is used. When the last oyster is used up, that date must be written on the tag you are keeping. You MUST write the last day the oyster was in your facility on the tag you are saving for 90 days. If you are using tubs of pre-shucked oysters with the tracking information documented on the lid, you must write the day the last oyster was used on the lid and save the lids themselves for 90 days as well.
Your menu must also contain a consumer advisory and disclosure for all raw or under-cooked proteins. Check out the fact sheet on Consumer Advisory from the Oregon Health Authority.