The flesh of healthy fish living in unpolluted ocean water is free of pathogenic bacterial contamination. If such flesh comes from a nonpoisonous fish, is properly stored for not more than half a day or so, and is correctly cleaned and prepared, eating sushi poses no more threat to your health than consuming a wholesome raw oyster or clam gathered from uncontaminated waters.
Unfortunately, many Japanese sushi bars serve less than perfectly fresh fish, and the seafood is not always hygienically handled. And to make matters worse, many of those sushi bars do not teem with customers during peak hours in the middle of the week. This increases the chances that the chef doesn't replenish his inventory on a daily basis. So it is recommended to enjoy sushi only at a quality Japanese restaurant that is busy every day and has a conscientious sushi chef with impeccable standards. You will pay more, but it is worth it.
** Asian Recipes