Answer to Question 1
Most seafood available in the United States and Canada is safe, but eating it undercooked or raw can cause severe illnesses- hepatitis, worms, parasites, viral intestinal disorders, and other diseases. Rumor has it that freezing fish will make it safe to eat raw, but this is only partly true. Commercial freezing will kill mature parasitic worms, but only cooking can kill all worm eggs and other microorganisms that can cause illness. For safety's sake, all seafood should be cooked until it is opaque. Even sushi can be safe to eat when chefs combine cooked seafood and other ingredients into delicacies.
Eating raw oysters can be dangerous for anyone, but people with liver disease and weakened immune systems are most vulnerable. At least 10 species of bacteria found in raw oysters can cause serious illness and even death. Raw oysters may also carry the hepatitis A virus, which can cause liver disease. Some hot sauces can kill many of these bacteria but not the virus; alcohol may also protect some people against some oyster-borne illnesses but not enough to guarantee protection (or to recommend drinking alcohol). Pasteurization of raw oysters-holding them at a specified temperature for a specified time-holds promise for killing bacteria without cooking the oyster or altering its texture or flavor.
Answer to Question 2
d