Sakanari notes that preparations like ceviche, in which fish are submerged in an acidic bath, do nothing to kill off anisakids, since they thrive in highly acidic environments. Candling—in which a strong light is shined through thin fish fillets placed on a glass, in order to spot parasites to be removed—is also not foolproof: Sakanari describes an experiment in which she and her colleagues examined a piece of rockfish using this method and determined that it was free of parasites. After cooking, they then flaked the fish fillet and examined it, and found that they had in fact missed several worms. Even experts can fail to completely deworm a fillet.
The upshot of all this: The only real way to be sure that you’ve eliminated any parasites in the flesh is by using temperature. “It’s best to properly freeze or cook the fish. That’s the bottom line,” Sakanari says. Is it worth the risk to eat raw fish that hasn’t been properly frozen? “It depends on how much you love the dish,” she says. “There are always risks to eating anything raw and improperly prepared or washed, so it is incumbent upon consumers to be aware of the risks and how to prevent the infections.”
