There's something about buying seafood that can make even the most confident shopper nervous.

Once, that decision boiled down to choosing the freshest fish. A host of other issues have clouded the picture now, from environmental pollutants to sustainability to food safety and antibiotic use.

EMAIL THIS PRINT THIS MOST POPULAR

Related: • Why country of origin can matter in seafood • More on food and drink • Search ajc.com's recipes Purchasing tips • Choose glistening, flawless fish that smells mild and fresh. Avoid strong fish odors or ammonia smells. • Whole fresh fish should have bright, clear, shiny eyes. Scales should be shiny and cling tightly to the skin. Look for bright pink or red gills. • Choose steaks and fillets that are moist and free of drying or browning around the edges. The flesh should be firm and spring back when pressed. • Frozen seafood should be free of ice crystals and freezer burn, and show no signs of thawed juices. • Don't buy cooked seafood, such as steamed shrimp or crab, if it's displayed in the same case as raw seafood because of the risk of cross-contamination. • If you want to buy fresh local seafood, learn its seasons. That's tough for something like red snapper, with seasons that may consist of three days here, three days there. It's easier with Georgia shrimp, which typically are available from May through December. • Soft-shell crab, wild striped bass, tuna and shrimp will be available soon from Atlantic and Gulf Coast waters in nearby states. How to store seafood • Put seafood on ice, in the refrigerator or in the freezer, immediately after buying it. • If seafood will be used within two days, store it in the coldest part of the refrigerator. Allow air to circulate freely around the package. Otherwise, wrap the food tightly to protect it from air leaks and store in the freezer. • Discard shellfish, such as lobsters, crabs, oysters, clams and mussels, if they die during storage or if the shells crack or break. Live shellfish close up when the shell is tapped. — Source: U.S. Food and Drug Administration, Anne Quatrano

A new federal seafood-labeling law will make some of those purchasing decisions a bit easier by letting you know more about the fish you buy. This week, supermarkets began labeling fresh and frozen seafood to disclose country of origin and whether it was farm-raised or wild.

There are a few basics to keep in mind, but many other factors are a matter of preference: taste, cost, farming practices and the seafood's country of origin. Figure out what's important to you, and buy accordingly.

Area chefs agree on one important basic, though: Get the freshest fish possible (and for consumers who don't have access to the same sources as upscale restaurants, sometimes that might be a frozen fish).

"Meat has weeks of shelf life. A fish is very different," Quatrano says.

"Rarely a fish order comes in that we don't return some of it, if not all of it. By far, it's the most perishable thing we work with."

They also prefer the taste of wild seafood, with just a few exceptions.

"The identity of the fish is there. After a while, farm-raised fish can all start to taste the same," Karatassos says. "When it comes to wild fish, wow, you really get to see what this fish is all about."

Fresh vs. frozen

Not part of the new law, although you'll find this information in many stores.

• Fresh: Seafood that is raw, has never been frozen or heated and contains no preservatives. Fish iced aboard ship and kept at temperatures just above freezing may be labeled as fresh when sold, even if it's been iced down on the boat for two or three weeks, then spent a few days in a delivery truck. Or it could be hauled out of the waters off Georgia just a day or two before purchase.

Why buy the freshest fish possible?

"It's more pristine," says Pano Karatassos, executive chef of Kyma. "The flavor is going to be brighter. It's going to be a cleaner taste. There's a big difference in a fish from the second day to the third day to the fourth day to the second week. It deteriorates. Which is not to say it can't be eaten."

• Previously frozen: Labeling for seafood that has been frozen, then thawed for sale.

• Fresh frozen, flash frozen: Seafood frozen while it's still fresh. Because fish spoils quickly, many processors freeze fish soon after harvest, whether it's from a fish farm or the ocean. Some large ships freeze fish as soon as it's caught. You're better off buying frozen-at-sea white fish, like cod, while it's still in a frozen state, rather than a previously frozen fish from the seafood case, advises Anne Quatrano, executive chef of Bacchanalia.

"Them thawing it out for you is not doing you any favors," Quatrano says.

Wild vs. farmed

Farmed fish provides nearly a third of all seafood. It can ease the strain on overfished species but, depending on the type of farm, may also cause environmental damage. Antibiotic use is another concern, especially the use of unapproved veterinary drugs.

The Monterey Bay Aquarium, which produces a guide to seafood issues, says farmed oysters, clams and mussels are a good choice. It also recommends tilapia, catfish and trout as good alternatives to ocean-farmed salmon or shrimp.

Why are antibiotics used in aquaculture? For the same reasons they're used in other large livestock farming operations: to reduce disease and promote faster growth.

It's a controversial practice, and some poultry processors are cutting back because of concerns that overuse may contribute to the growth of antibiotic-resistant bacteria. In recent years, McDonald's has asked its suppliers to curb antibiotic use, and Perdue has stopped feeding antibiotics to its flocks to promote growth.

The FDA must approve antibiotics used for livestock, but companies in some countries have been using unapproved or banned antibiotics for fish farming. One such antibiotic, chloramphenicol, has been tagged as a potential carcinogen and linked to aplastic anemia and reproductive system problems.

State and federal agencies stepped up testing for chloramphenicol after it turned up in imported shrimp, crawfish and crab, as well as honey. How widespread was the problem? In Louisiana, 10 percent of all imported shrimp tested since 2002 has shown traces of the drug. The problem is decreasing, says Benjy Rayburn, who directs the agriculture department division that conducts the sampling program. He chalks that up to the state's decision to destroy all contaminated shipments.

The FDA has just started a testing program for other banned substances — the fungicide malachite green (in imported farmed salmon) and antibiotic nitrofurans (in shellfish) — but hasn't compiled results yet.