Although it might seem that fresh fish would a healthier choice than frozen, the truth is that both fresh and frozen fish can be healthy choices, as long as you store and prepare them properly. The freshness of the fish, along with how it was frozen and how quickly it was frozen, can impact its taste and texture, as well as its bacterial content.
Both fresh and frozen fish can spoil. Eating fish within a few days ensures that it doesn't have time to spoil. Store fresh fish for no longer than one to two days in the refrigerator before eating. Frozen fish can spoil if it thaws during transport. Look for signs of possible spoilage, such as rips or tears in the packaging. Don't refreeze seafood once it thaws. If you buy frozen fish, don't pick packages stored above the chill line. If fresh fish has an ammonia-like odor, it might be starting to spoil.
Freezing fish halts bacterial growth that can make you sick. Eating fresh fish or keeping it in the refrigerator can also retard bacterial growth. Undercooking fish is the main cause of bacterial infections contracted from fish, such as shigella, salmonella, vibrio cholerae, staphylococcus or clostridium. If you don't thaw fish thoroughly before cooking, slightly frozen areas might not cook all the way through. Cook to an internal temperature of 145 degrees Fahrenheit. Bacteria also can grow during the thawing process, if you thaw fish in warm environments such as the kitchen. Thaw fish in a bowl of cold water or in the refrigerator.
Freezing doesn't reduce the nutritional content of fish, in most cases. Protein, fat and fat-soluble vitamins such as vitamins A and D aren't affected by the freezing process itself. But when you thaw the fish, you can lose some of the water content as the fish thaws. The water can contain some of the water-soluble vitamins and minerals. If you use all the water lost from the fish for cooking, you will retain the vitamins and minerals. Because fresh fish doesn't lose any of its water content, it won't lose any vitamins or minerals.
Taste and Appearance
While they don't affect your health directly, the taste and appearance of fish can affect your willingness to eat it. Because fish contains lean protein and essential omega-3 fatty acids, it's a valuable addition to your diet. Most people can't tell the difference between fresh and appropriately frozen fish, the Alaska Seafood Marketing Institute says on the What Cooking America website. Fish can turn slightly mushy, with an unappealing texture, if thawed in warm water or in a warm room.