I'm relatively new to cooking and I was thinking about pan frying salmon. All of the recipes on the internet say to cook it until it has a "pink center", which I am assuming means just a bit undercooked. So I went to buy a filet today and basically the butcher told me that the salmon he sold was not "sushi grade" and therefore, he wouldn't recommend eating it slightly undercooked.
My question is, how do I know if the fish is "good" And i guess the question applies to the beef too. How would I know if like a rib eye is safe to eat med-rare? Because doing it well done seems like a waste