Getting Sick of Sushi?
What are the dangers of sushi, assuming it is prepared in a clean environment?
Since sushi became the rage about a decade ago, there's been a lot of concern about how safe it is to eat. In fact, problems with sushi occur very rarely, but when they do, they can be very unpleasant. The fish to watch out for are primarily mackerel and salmon. Also, I wouldn't eat raw cod or herring.
The problem is that a few species of fish can carry a parasitic worm. This worm normally inhabits fish-eating birds, but finds humans quite attractive as hosts when accidentally introduced - such as at a sushi bar. Inside a person, these worms can ulcerate the stomach and be extremely painful. The worms typically are from the Anisakinae family, but they may also be members of other species. (Since smoking doesn't necessarily kill these parasites, lox is also suspect, as are gravlax and pickled herring. Usually cooking the fish or freezing it for five days will kill these worms.)
But I think sushi has taken a bit more than its fair share of the blame here. Overall, very few people get sick from eating sushi, and most infections from parasitic worms occur from fish eaten at home, not from restaurants. In other words, you're more likely to buy contaminated fish at your local supermarket than get it at a Japanese restaurant.
Still, if you eat sushi, keep in mind that the fish must be really fresh. It should smell sweet, not "fishy." You probably don't want to try sushi in a bar in Ohio, for example.
While you're worrying, watch out for the wasabi. This is the very hot green horseradish used to flavor sushi, and it's great stuff. But in some people it can trigger an autonomic nervous system response that may include intense sweating, pallor, and confusion.
The other concern, as always with fish, is whether it carries toxic contaminants. Shellfish in particular are more likely to have picked up toxins and pollutants because of their feeding habits. Don't eat raw mollusks, because they can transmit a variety of diseases, including hepatitis. Bluefish, tuna, swordfish, and marlin can concentrate toxins in their bodies as pollutants move up the food chain into the mouths of these big fish.