The word “fresh” has cache to it. Think of a tomato fresh off the vine or fresh-squeezed lemonade. But when it comes to describing seafood, the word doesn’t always mean better quality.
Technically, “fresh” seafood has never seen temperatures below minus 1 degree Celsius, whereas “frozen” seafood has. But does that fact alone make fresh better? Geoff Shester, Ph.D., California Program Director for Oceana, says not necessarily so. “The way I think about it is would you rather eat “fresh” seafood that’s been sitting on a boat for seven days unfrozen, or a product that has been frozen in such a way to retain the moisture, flavor and texture indistinguishable from fresh seafood?”
Freeze Fast
Most people understand that storing a fish below freezing inhibits cellular degradation. But storage is only part of the equation. According to the Food and Agriculture Organization of the United Nations (FAO), the first step to keeping quality high is freezing … fast.
Fish are made largely of water. During the initial stage of freezing, a fish’s temperature drops to just below 0 degrees Celsius. But at that temperature, only a small amount of the water in the fish has actually crystallized into ice. While the rest of the conversion takes place, the temperature levels out between 0 and -1 degree Celsius during a period called “thermal arrest.”
This conversion of water to ice can take hours—or days—and the slower it occurs, the more quality drops. According to the FAO report, this has more to do with the biochemical denaturing of proteins than it does rupturing of cells from ice crystallization. Reducing temperature below -5 degrees Celsius as fast as possible, preferably within a couple of hours of catch, minimizes denaturation and preserves the integrity of the fish.
Consider the Big Picture
There’s something else to be said for frozen fish … they have a smaller carbon footprint (or fin print?) than fresh fish that have been flown in from afar. According to Bon Appetit Management Company, an advocate of freezing fish at sea, shipping fresh fish by air generates ten times the greenhouse gas as transporting frozen fish by container ship, and five times more than by truck.
Use Your Senses
So what does this all mean at the fish counter? That frozen options—particularly items like shrimp and smaller fish filets—may actually be fresher than what’s labeled fresh. But without knowing what method was used to freeze the seafood, the best way to evaluate is to use your senses. Avoid anything—fresh or frozen—that:
- Looks discolored or mushy
- Feels mushy to the touch
- Smells “fishy” or like ammonia
- Tastes “off”
Personally, I take sustainability, quality and locale into consideration in choosing my fish—not whether it’s fresh or frozen. If I see a locally caught sustainable pick that looks delectable … fantastic, whether fresh or frozen. If I have a choice between “fresh” shrimp that are looking a bit peaked and frozen, sustainably raised ones, I’ll choose the frozen.
Fresh tomatoes are one thing, but don’t let “frozen” dissuade you from choosing high-quality seafood.
1 tablespoon canola oil
