Earthy tasting frozen salmon I got out some wild sockeye salmon that had been in the freezer for quite a while (several months at least, not more than a year). It was vacuum-packed, no freezer burn, sealed properly, etc. I cooked it very well but while it smells and looks okay it tastes earthy and a bit undercooked (even though it's flaky and opaque). The texture is fine. I stopped eating it but wondering what this is about. 

I cut it in half while it was still raw and washed the knife and then used it for salad ingredients. If the knife wasn't washed well enough could the raw salmon cause me a problem? Thanks!

Edit: Does anyone know what the taste might mean? Or if it might mean it's not really edible? I did eat a bit and am fine but I guess we have taste buds for a reason so I should probably avoid it. I am curious as to what might have gone wrong.
Not likely. Wild salmon is pretty low on the list of foods that can cause harm because of cross-contamination, particularly salmon that has been frozen for an extended period of time. Undercooked fish is considered risky more because of potential parasites than bacteria. Months in the freezer is going to pretty much eliminate any risk of consuming a live parasite. Plus, the toxins that can be found in fish are not particularly common in salmon. If the fish didn't spend too long in the "danger zone" either before or after freezing, you've got very little to worry about.