Play It Safe With Oysters by Turning Up the Heat

Citing recent illnesses associated with raw or undercooked oysters, the state health department is urging consumers to eat only oysters that have been thoroughly cooked.

* Individuals with weakened immune systems, liver diseases, diabetes or other chronic illnesses or who are taking daily doses of stomach antacid are especially susceptible to illness from eating raw or undercooked oysters.

* The cause is Vibrio parahaemolyticus, a natural marine bacteria common during periods of warm weather. Infections can cause diarrhea, abdominal cramps, nausea, vomiting, headache, fever and chills.

* Symptoms usually appear 12 to 24 hours after eating. Most illnesses end after two to four days. This illness is rarely fatal, but severe cases may require antibiotics and hospitalization.

* Warm summer temperatures can increase the number of Vibrio parahaemolyticus organisms in shellfish to levels that cause illness. All shellfish--especially oysters, mussels and clams--should be kept refrigerated. Inadequate refrigeration after harvest and during transport, storage and display can greatly increase the risk of illness by allowing the organisms to multiply.

* Cooking can be very effective in killing the Vibrio parahaemolyticus bacteria, but oysters that are steamed, barbecued or served “Rockefeller-style” may be undercooked. Officials advise that the internal temperature of the oysters reach at least 145 degrees to kill the bacteria. Merely marinating oysters in lemon juice, vinegar, cocktail sauce or other marinades does not provide protection.

* Health officials advise consumers who wish to reduce their risk of food-borne illness to avoid eating raw or lightly cooked foods of animal origin, including beef, eggs, fish, lamb, poultry and shellfish. Thorough cooking is the best way to eliminate bacteria from these products.

* Since 1991, the state has required restaurants, markets and other retailers that sell Gulf Coast oysters to conspicuously display a warning about the risk of eating them. Regulations prohibit retailers from receiving raw oysters if their origin is not clearly identified, and they require the retailer to retain shellfish identification tags for 90 days. State regulations also require dealers and retailers to maintain records to rapidly identify the sources of shellfish linked to illnesses. Questions on where oysters were harvested should be asked of the retailer or oyster supplier.

Source: State Department of Health