You rinse the salmon. The USDA cautions: “do not rinse raw fish, seafood, meat, and poultry. Bacteria in these raw juices can splash and spread to other foods and surfaces. Cooking foods thoroughly will kill harmful bacteria.”
You don't need to rinse fish, chicken, pork, or any other meat before cooking. Not only does it not get rid of bacteria, it spreads bacteria (if water splashes from the sink in the process of rinsing). What kills bacteria much more effectively is cooking.
Per WebMD, fish is similar to poultry in that washing it raw can cause any bacteria to spread around your sink and kitchen, increasing the likelihood you will get sick. Raw fish is known to contain dangerous bacteria, including salmonella, listeria, and clostridium.
It's not unsafe, but it will decrease the quality of the salmon. The flesh will most likely disintegrate before reaching cooking temperature. Once it is cooked, it'll just crumble, the extra water will turn it into mush, and be quite unpleasant to eat.
Brining a fillet of fish allows salto to soak into the flesh, infusing flavors deep inside while also keeping the fillet tender and juicy as it cooks. No matter the subsequent cooking method, it's a surefire way to make the fish richer and more succulent.
Soaking in brine also means that the fish will be much juicier and tastier after cooking, and it prevents the fish becoming too dry should it be cooked a little longer.
Ultimately, it's up to you whether or not you want to clean your salmon with vinegar. If you decide to go ahead with it, be sure to cook the fish immediately afterwards. And if you're worried about bacteria, consider adding a bit of salt to the vinegar solution, as that can help kill unwanted microbes.
But there are a couple tricks if you want to avoid it. One option is to brine the fish. America's Test Kitchen recommends soaking the salmon in a standard brine—one tablespoon of salt per cup of water—for just 10 minutes before cooking. That should minimize the amount of albumin forming on the surface of the fish.
While washing meat and poultry to remove dirt, slime, fat or blood may have been appropriate decades ago when many slaughtered and prepared their own food, the modern food safety system doesn't require it. Meat and poultry are cleaned during processing, so further washing is not necessary.
Fish is in the same category as poultry and red meat: If you wash it, you will spread bacteria around your kitchen. Cook it off instead. The only exceptions to this rule are clams, oysters, mussels, and scallops that you get fresh. They may need a rinse to get rid of sand and dirt.
After reading through the thread, it is clear to see that most do agree that freshwater is not the best thing for the fillets, as it may make them mushy after being packaged and refrigerated or frozen.
Dry fish: It used to be recommended to rinse fish before baking, but fear of splattering harmful bacteria that might be on the fish changed that. We recommend not rinsing unless you need to rinse off any scales. Pat dry with paper towels whether you rinse or not.
Removing the scales from a salmon's silvery sides is not a necessity, but many cooks prefer to de-scale the fish before putting it in the oven or on the grill to prevent the errant scale or two from despoiling the presentation of the fish on the plate.
Albumin is a liquid protein that solidifies when the fish is cooked, seeping out as the muscle fibers contract under heat, becoming thick and a bright white. Think of your salmon as a wet towel being rung out. The wringing is the heat and the water being pushed out is that white stuff you're seeing.
Pat seafood dry before cooking.
You can prevent your fish fillets from having an unpleasant mushy texture by using a paper towel to pat each one dry before cooking. Removing this moisture from the outside of the fish won't make the meat dry out. Instead, it will ensure that it has the right flaky texture when it cooks.
And when you cook salmon, white gunk oozes out, so you'd be forgiven for thinking that was fat too. But it's not. It is in fact a highly unappealing substance called coagulated protein, or albumin. A lot of people think the white substance is fat and so try and wipe it away, but it's actually completely safe.
The White Stuff on Salmon is Perfectly Normal
To get an expert opinion, I spoke to our Executive Culinary Director Sarah Farmer, who explained that it's a harmless protein called albumin. According to her, “It's nothing to be scared of and it's totally safe to eat, but I think we would all admit – it's nasty.”
What is it? Well to be short: albumin and it's a protein that happens when you cook the salmon. It's edible and totally fine. To be long: it's albumin, a protein that is originally liquid in the fish that turns semi-solid as it cooks and comes out as this oozing white stuff that is totally fine to eat but freakish.
Put the salmon in the dish and pour the vinegar over the salmon. Move the fish around and be sure to wet the entire piece of fish with the vinegar. Pour off the vinegar. Allow the fish to “marinate” for 15 minutes (10 minutes for leaner salmon).
By giving a fillet a vinegar rinse (or even a full-on soak while you prepare the rest of your meal's components), you can bring out all of the fish's best qualities and textures, neutralizing any fishy scents while seasoning it.
As it does with meat, brining fish serves two purposes: One, it helps season the flesh, which improves flavor, and two, by partially dissolving muscle fibers to form a water-retaining gel, it helps prevent the protein from drying out.
Don't rinse off the marinade before cooking salmon. You worked hard trying to impart that extra flavor, so you don't want to lose it. However, do discard the marinade after removing the fillets. Because the marinade came in contact with raw fish, it's no longer safe to use.
Soaking salmon in a simple, quick brine for as little as 10 minutes (up to overnight, if you like planning ahead) is all it takes. To make it happen you need two very basic ingredients: water and salt. Combine 1 tablespoon of salt for every cup of water.