Last Friday I opened a package of 2 local beef/pork sausage and today (3 days later) it's marbled with a grey color (still pink inside and some of outside and smells perfectly fine). Is this OK to eat?
Grey is a bad sign. But it can also mean that the butcher who made it didn't use nitrites which are what keep the meat pink looking. Some people object to nitrates. Three days is really not long enough for an uncured sausage to spoil if refridgerated but then you probably don't know the day when it was actually made. Caution!
I would agree with pierino, except when there is a lot of fresh garlic in the sausage. Garlic reacts with the ground meat and turns it grey rapidly.