The FDA and the coastal states all test for these blooms, and when they appear the waters are closed to all fishing. Even oysters taken from clean waters occasionally harbor a naturally occurring, unfriendly bacteria known as Vibrio vulnificus , according to a recent report from the National Centers for Disease Control and Prevention. If contaminated mollusks are eaten raw and the bacteria remains alive, it can make a person very sick. Healthy people will probably just get a bout of indigestion. But for those with liver ailments and depressed immune systems, Vibrio vulnificus can be deadly.
Symptoms can include sudden chills, indigestion, fever, nausea, vomiting, and stomach pain.
According to the National Academy of Sciences report, catfish, trout, salmon, and other farmed species are generally reliable as long as they are cooked immediately before serving. Processed fish such as fish sticks and fish nuggets are also safe bets because they are made from white-fleshed fish such as cod, haddock, and pollack. And canned tuna is not only the safest of all seafoods, but it is also the most popular. No matter what the fish, there are some simple precautions you can take when shopping for and storing seafood, though. It should not smell unpleasantly fishy.