When it comes to defrosting fish, there are a few different methods you can use – thawing in the refrigerator, soaking in cold water, or microwaving. The slow thaw method of placing fish in the refrigerator overnight is generally recommended as the safest approach. However, busy home cooks often look for quicker ways to defrost fish like using the microwave or soaking in water. So is it actually safe to defrost fish quickly using these faster methods? There are a few factors to consider.
Safety Concerns with Quick Thawing
The main safety concern with quickly thawing fish is the potential for bacterial growth. Fish is highly perishable and prone to bacterial contamination even when frozen. The reason slow thawing in the fridge is the safest method is because it keeps the fish consistently chilled as it thaws, preventing bacteria from multiplying rapidly as the fish warms up. Quick thawing methods like microwave defrosting or cold water soaking can warm up parts of the fish and create temperature variances that allow bacteria to flourish.
Another issue that can occur with quick thawing is uneven thawing. Microwaving can lead to cooked sections on the outside while the inside remains frozen. Soaking can also result in uneven thawing. Uneven thawing is problematic because the raw interior sections could harbor bacteria even after the exterior seems thawed. Cooking fish that is not thoroughly thawed all the way through can also negatively impact texture and flavor.
Proper Handling for Safe Quick Thawing
While quick thawing does come with some risks, you can take steps to mitigate those risks. Proper handling and cooking can make quick thawing acceptably safe. Here are some tips:
– Use the microwave defrost setting at a low power level if microwaving fish. Stop halfway through and check for thawed portions. Turn over and rearrange to promote even thawing.
– When soaking fish in cold water, change the water every 30 minutes so it stays cold. Use ice water. Thin fillets will thaw quickly, while thicker steaks or whole fish may take an hour or more.
– Cook fish immediately after thawing using a method like grilling, sautéing, or baking that heats the fish thoroughly to an internal temperature of 145°F. Don’t let thawed fish sit at room temperature.
– Rinse fish under cold running water before cooking to wash away any bacteria that may have accumulated on the surface during thawing. Pat dry with clean paper towels.
– Only thaw as much fish as you plan to cook and eat within the next day. Don’t refreeze thawed fish.
Quick Thawing Methods Reviewed
Let’s take a closer look at the two main quick thawing methods and their proper use:
Microwave Defrosting
– Use the defrost setting at 30-50% power. This allows gradual, even thawing.
– Don’t microwave at full power as this can start cooking the fish before it’s fully thawed.
– Place fish in a microwave-safe dish, uncovered. Add a little water if needed to prevent drying out.
– Stop halfway and rearrange fish for even thawing. Check for any cooked portions.
– Cook fish immediately after microwaving to destroy bacteria.
Cold Water Soaking
– Use ice cold water, under 40°F. Add ice cubes to keep it cold.
– Place fish sealed in a zip top bag or airtight container when soaking. Helps prevent contamination.
– Change water every 30 minutes so it stays cold.
– Soak thin fillets for 30 minutes, thicker cuts for 1 hour. White fish thaws faster than oily fish like salmon.
– Cook fish right after thawing, don’t allow it to sit and get warm after removal from the water.
Steps for Safe Quick Thawing
To recap, follow these key steps when quick thawing fish:
1. Use microwave defrost on low or soak in ice cold water with frequent water changes
2. Cook fish immediately after thawing using a high temperature cooking method
3. Check fish for any uneven or under thawed portions before cooking
4. Rinse fish before cooking and sanitize any surfaces it touched
5. Only thaw the amount that can be eaten within a day and don’t refreeze
Quick Thawing Large Whole Fish
Thawing large whole fish like salmon or rockfish presents some particular challenges. Microwaving a whole large fish is difficult since most home microwaves aren’t big enough. Soaking is the better option for whole fish but they can take many hours since the interior thaws slowly. Here are some tips:
– Place the wrapped whole fish in a large container and cover with ice water. Use a cooler if your sink or tub doesn’t accommodate it.
– Change the water every 30 minutes, replenishing ice cubes to keep it cold.
– Figure on about an hour of soaking time per inch of fish thickness. A 3-inch thick whole salmon may take 3 hours or more.
– Check frequently and turn the bag over occasionally to promote even thawing.
– When thawed, sanitize the sink, tub, or cooler used for soaking. Don’t use it for food prep until sanitized.
– Rinse fish, pat dry, and cook promptly using a high-heat roasting method. Roast at 400°F until 145°F internally.
Quick Thawing Fish Fillets
For thinner fish fillets, steaks, and cuts under 1 inch thick, you have more flexibility for quick and safe defrosting:
– Microwave defrosting works well for fillets, stopping halfway to rearrange.
– A 30-minute ice water soak should sufficiently thaw thin fillets.
– The refrigerator method overnight is ideal if you have time. Place fillets in a bowl or pan to catch drips.
– For skillet cooking, shallow fry, or sautéing you can actually just cook frozen fillets on medium heat. The cooking will thaw and cook the fish. Add a minute or two to the usual cooking time.
Quick Thawing Shellfish
Shellfish like shrimp, scallops, and crab can be quickly thawed with minimal risk:
– Their small size lets them thaw rapidly in an ice water bath in as little as 20 minutes.
– You can also thaw frozen shellfish under cold running water directly in the sink. Use a colander.
– Microwave defrosting works for shellfish but watch closely for any cooking and stir/rearrange frequently.
– Cook thawed shellfish right away, their delicacy means they can’t withstand sitting at room temperature for long.
Is Refreezing Thawed Fish Safe?
In general, it is not recommended to refreeze fish after thawing. Any bacteria present can grow rapidly as the fish thaws and will simply be preserved again when it’s refrozen. The quality of the texture and flavor also tends to degrade with each freeze-thaw cycle.
However, if fish is thawed properly in the refrigerator using the slow cold method, it may be safe to refreeze it. The key factors are:
– The fish remained chilled below 40°F throughout thawing
– No discoloration, off odors, or slime developed during thawing
– It was thawed for no more than a day or two before deciding to refreeze
– The fish is immediately frozen, wrapped air-tight, and not left to sit in the freezer
The risks are lower for fish thawed slowly and properly in the fridge. But in general, refreezing thawed fish is still not considered the safest practice. Always cook thawed fish within a day and don’t attempt to refreeze if using a quick thaw method.
Storing Thawed Fish Safely
After going to the trouble of properly thawing fish, you want to make sure and store it safely before cooking:
– Keep thawed fish chilled in the refrigerator below 40°F until ready to cook. Use within a day.
– Place fish on a plate or in a container to prevent raw juices from dripping on other food.
– Sanitize any counters, cutting boards, plates or utensils that contact the raw fish before and after use.
– Never allow thawed fish to reach room temperature. Bacteria multiply rapidly at 40-140°F.
– Prep and serve thawed fish on the same day, don’t try to store thawed fish back in the fridge after cooking it.
Cooking Thawed Fish Safely
The final step in safe fish handling after thawing is proper cooking. Thorough cooking destroys potentially harmful bacteria:
– Cook fish to an internal temperature of 145°F. Use a food thermometer to check.
– Allow fish to rest 3 minutes after cooking before serving. The temp will rise a bit more.
– Discard any marinades used on raw fish after cooking. Don’t reuse.
– Don’t eat raw fish unless it was previously frozen according to FDA guidelines to kill parasites.
– When pan-frying or sautéing, use high heat and cook fish 2-3 minutes per side until opaque and flaky.
– Grill over direct high heat 4-5 minutes per side, turning once. Don’t overcook.
– Bake fish at 400°F approximately 10 minutes per inch of thickness.
Conclusion
While thawing frozen fish slowly in the refrigerator overnight is ideal, using faster quick thaw methods can be acceptably safe with proper handling. Microwave defrosting and cold water soaking both allow fish to be thawed in well under an hour. But care must be taken to prevent bacteria growth with quick thawing methods. Cook fish immediately after thawing, sanitize surfaces, rinse fish before cooking, and discard used marinades. Quick thawing should only be used if the fish will be cooked and consumed within a day. With proper precautions, quicker defrosting can allow even busy home cooks to enjoy fish any night of the week.