Sushi was only introduced into the American dining scene in the 1960s, but many of us have accepted raw fish with open arms. Despite how often we eat it, there’s a common misconception about sushi that we’re going to dispel today. It has to do with the freshness of fish.
Many people believe that in order for sushi to be safe to eat, it must be really fresh. But, in fact, the opposite is often true. For many species of fish ― especially fish like salmon that have spent time in fresh water ― the safest way to eat raw fish is if it’s been previously frozen. And sometimes that means it can be frozen for up to two years, reports The New York Times. Peter Cassell from the FDA says, “Freezing is the only practical method in current use” to control a parasite hazard.
Freezing eliminates the risk of parasites.
Freezing kills parasites ― such as nematodes or Diphyllobothrium tapeworm larvae ― found in the fish’s flesh. When cooked, these parasites are killed. But if eaten raw they pose a risk.
That is why the FDA recommends that fish that is served raw ― we’re talking sushi, ceviche and tartare ― be frozen first. The FDA Food Code states that fish eaten raw should be frozen at -4 degrees Fahrenheit for a minimum of seven days, or for 15 hours at a temperature of -31 degrees F. In New York City, the Health Department has mandated that federal recommendation. But for other parts of the country, the FDA guideline on freezing fish is just that, a guideline.
But not all seafood has to first be frozen.
Shellfish, certain species of tuna, and certain types of farm-raised fish are exempt because they do not pose the same parasitic threat. Farm-raised fish live in a controlled environment, so the risk of parasites can also be controlled. And tuna, it turns out, has exceptionally clean flesh.
Though these days, tuna is often frozen in order to meet the demand for it when the fish is out of season. The practice of freezing tuna has even become commonplace in Japan.
Not all sushi restaurants freeze their fish.
It all depends on their budget and location.
HuffPost talked to Ben Steigers, executive chef at Pabu in Boston, about his restaurant’s practice with freezing fish. They actually freeze very little. Salmon is always frozen to control the risk of parasites, and tuna is usually previously frozen because fishermen freeze it when out at sea. But the rest, he says, is generally served fresh. That’s because Pabu has the luxury of being able to pay the price tag for fresh fish, and his restaurant is also situated in Boston, which brings in a lot of fresh fish.
When asked about the FDA recommendation, Steigers responded, “It’s along the same lines of the FDA recommendations that you order your steak well-done for safety reasons, but how many restaurants actually serve their steaks all well-done? I can’t name a single one. The FDA’s job is to protect the safety of people over the deliciousness of the food,” Steigers told HuffPost.
But restaurants without that location and budget, Steigers says, most likely serve a lot of frozen fish. “Fish is definitely one of those things where you really do get what you pay for. It’s so expensive not just to catch the fish, but the shipping of the fish,” Steigers explained. That’s why frozen fish is more common in budget sushi restaurants. “As you go down the line you will find more and more frozen fish because frozen fish tends to be cheaper, so you don’t have to spend so much in transportation.”
Freezing doesn’t have to mean a lesser quality sushi.
The reason freezing has such a bad reputation is because “freezing expands the water in the cells of fish, which disrupts the cell membrane and breaks down the fish. That’s why frozen fish doesn’t have the same luster, texture and it seems mushy,” explains Steigers. But new freezing technology ― using freezers that chill at -60 degrees Fahrenheit ― have made it so that freezing hardly affects the texture cell membranes in fish.
While this frozen-first fact might make you a little less excited about your Saturday night sushi outing, you should know that one of the most acclaimed sushi chefs swears that with freezing technology as good as it is today, you can’t even tell the difference between fresh and frozen in a blind tasting. Shin Tsujimura, chef at Nobu, told the New York Times that even he couldn’t tell the difference.
So, chances are, neither can you.