MISSISSIPPI STATE -- Preparing beef, pork or chicken may be routine to some people, but catching on to the tricks of cooking seafood that is delicious and safe can be a bigger challenge than the catch itself.

Overcooked seafood can become rubbery and tasteless, while raw or undercooked seafood can pose many health risks. With a little extra care, seafood can be a delicious and safe addition to a family's menu.

Melissa Mixon, human nutrition specialist with Mississippi State University's Extension Service, said although some seafoods traditionally have been served raw, this is not the safest option.

"It's a good idea to cook all seafood thoroughly to avoid any health risks," Mixon said. "This includes finfish, oysters, shrimp and other shellfish."

The nutritionist recommended checking all cooked seafood for the proper degree of doneness:

• Fish is thoroughly cooked when the flesh turns opaque and flakes easily with a fork.
• Shrimp are completely done when they turn pink and the tails curl toward the heads.
• Scallops are cooked thoroughly when they are milky white and firm to the touch.
• Oysters and clams are fully cooked when they become plump and opaque, and the oysters' edges curl.

The 10-minute rule is a helpful way to decide on the length of time finfish such as catfish, salmon, flounder or haddock should be cooked. Measure fish at its thickest point, and cook it 10 minutes for every inch of thickness, turning it over halfway through the cooking time. Double the time for frozen fish that has not been thawed.

Undercooked or raw seafoods can pose many health risks. Fresh-shucked raw oysters have long been a favorite appetizer, but for many people the tab for this delicacy can be fatal.

The nutritionist said a naturally occurring bacteria in raw oysters can have potentially lethal effects.

The U.S. Food and Drug Administration has estimated eating raw oysters containing the bacterium vibrio vulnificus causes about 15 deaths each year.

"The bacterium is naturally occurring and has nothing to do with the cleanliness of the waters the oyster was grown in," Mixon said. "This bacterium won't hurt everyone, but it poses a serious threat to people with certain medical conditions, including kidney, liver and GI tract diseases; diabetes, and people with weakened immune systems."

People with these medical conditions who eat raw oysters containing the bacteria risk the side effects of severe diarrhea, vomiting and fatal blood poisoning.

Cooking the oysters is an easy method of destroying the bacteria, the nutritionist said.

For more information on safely preparing seafood, contact the U.S. Department of Agriculture's meat and poultry hotline at 1-800-535-4555 or your local county home economist.