As far as cult classics go, McDonald’s Filet-O-Fish is right up there with the best of them. Love it or hate it, the sandwich has thrived for more than 60 years. It does, however, have a fishy horror associated with it. The Filet-O-Fish has four simple ingredients: a crispy fried fish filet patty, tartar sauce and a half-slice of cheese on a plain steamed bun. It’s made with wild-caught Alaskan pollock sourced from sustainable fisheries, and it’s cut right from the fish — no chopped and formed patty here. What else might be in your Filet-O-Fish? Okay, deep breath. You might actually find a dead worm in your sandwich. That’s right, it turns out that nematodes — a type of roundworm — are commonly found in saltwater fish such as pollock, cod, flounder and halibut. Small numbers of these worms are normal and commonly present in healthy, wild-caught fish. “Nematodes get into fish through the ocean food chain,” said Kimberly Baker, Director of Food Systems and Safety at Clemson University. She went on to explain that fish like pollock, which McDonald’s uses, will eat small fish or crustaceans that have eaten the worms, and then the worms will move into the larger fish. “If anything, it tells you that it’s real fish,” said Baker. It has nothing to do with McDonald’s food-prep techniques or cleanliness. In fact, it’s likely you’ve ingested these tiny worms before. They aren’t dangerous, because they’re always dead when you eat them, thanks to the fish frying process. The only way the parasites can cause problems is if they’re consumed while still alive, which is why you should never eat raw fish. If you're worried about worms in seafood, the only real way to avoid them is to not eat seafood. So, the next time you order up a Filet-O-Fish, don’t be surprised if there’s a deceased hitchhiker in the mix.
