Salmon tartare--eye-catching, fun, hip and tasty--has become a popular menu item in many top restaurants. Celebrity chefs prepare it on television. Mainstream magazines, newspapers, and cookbooks feature recipes. Raw salmon dishes--tartare, crudo, sushi, marinated and cured salmon--are growing in popularity. But unless that fish has been frozen first, it would be wise to pass.
That's because a tiny tapeworm larva may lurk in the raw salmon flesh, just waiting for you to eat it so that it can take up residence in your digestive tract. Diphyllobothrium latum, carried by freshwater fish (including anadromous wild salmon, which spend their early lives in fresh water), is the largest human tapeworm. After the larva is ingested by a fish-eating mammal, it hooks onto the small intestine, where it grows to maturity, freeloading on its host for nutrients (it has a special affinity for Vitamin B12). Cooking fish or freezing it at minus 31 degrees Fahrenheit or colder for 15 hours will kill Diphyllobothrium larvae. Marinating will not. Freezing fish at slightly higher temperatures for longer periods will also kill the larvae but will likely diminish the quality of the fish.
Just this week, a Chicago man sued a well-known local restaurant for $100,000, claiming that he had acquired a nine-foot tapeworm from an undercooked salmon salad in 2006.