Fish and seafood are a great source of a high-quality protein, unfrozen fish may actually be less fresh than fish you buy frozen.
Fish and seafood are a great source of a high-quality protein, long chain omega-3 fatty acids, and vitamins and minerals. It is also low in saturated fat.
Because of all these benefits, the Dietary Guidelines for Americans (2015-2020) recommends eating eight or more ounces of fish and seafood every week.
When you’re watching your food budget, however, fish may seem expensive. One strategy is to choose frozen fish, which tends to be cheaper, and fresher.
Is fish better frozen or thawed?
Most of the fish you see in U.S. stores unfrozen has been frozen, imported from far away, and thawed before you find it on a bed of ice.
If you live within a 100 miles of a coast or Great Lakes, you can go for local fish while it’s in season.
Otherwise, a better bet is a fish that was caught on a small fishing boat, perhaps in Oregon or Alaska. Modern boats now have freezers that are much colder than yours. Fish is now flash-frozen on the boat or within hours when it was dropped at dock — then vacuum-sealed.
Consumers rated wild Oregon and Alaska flash-frozen fish as tastier than products that were thawed, in studies conducted by researchers at Oregon State University, a seafood certification company, and the environmental group Ecotrust.
In unlabeled samples, the consumers tried cooked flash-frozen salmon, sablefish (also called black cod), albacore tuna, rock-fish and scallops, and the same species bought that morning from a high-end grocery.
The research also included objective testing measuring how much the flesh had changed over time. In one study, the store-bought cod rated 15 out of 100 in a test. Salmon rated 20. Meanwhile, flash-frozen cod tested at 80, while salmon rated a 79.. Fish register at 100 when it has just been caught. After a few weeks, it will test at 10 or less.
If you buy frozen farm-raised fish, it also is likely to be fresher than the same product sold thawed.
When you buy frozen fish, look for a vacuum seal. Avoid products with sodium tripolyphosphate, a chemical added to retain moisture that also adds to the weight and cost. Freezer burn or crystallization suggests the fish has been thawed and refrozen, which won’t taste good.
If you do choose thawed fish, never buy fish from a store that smells fishy, or fish that smells strongly. It should smell like the sea.
Frozen fish can keep for months in a good home freezer. When you’re ready to use it, you can cook it frozen. Steaming, roasting, or poaching will work. If you want to cook it in frying pan, you need to thaw it. Remove it from the vacuum-sealed packaging, and put it in a zip-top bag and run it under cool running water. You can also place it in a bowl of water that you change frequently over about 15 minutes to an hour.
What about parasites or mercury?
The risk of getting parasites from fish is low, even when you eat it raw as sushi. The U.S. Food and Drug Administration (FDA) recommends that any fish served raw, except tuna, be frozen first to kill parasites, and in some places the rule is a requirement.
The FDA also advises Americans to limit swordfish, king mackerel, tilefish, and big eye tuna as most likely to contain mercury, which is dangerous for small children and women who are breastfeeding or pregnant. If you eat fish caught locally, check local advisories for mercury risk.
July 15, 2020
Janet O'Dell, RN