Ive been smoking my own deer summer sausage for a while know and always had good results. This year I did everything the same except I used pork callies instead of pork butts to mix with my deer meat( was much more fat). Anyway after using same procedure for smoking as I normally do, I removed SS at internal temp of 155 degrees, Looked good tasted great, but I could tell there was more pork fat than normal. Slightly different texture but still really good. Next day I sliced up a stick and threw it in a plastic zip loc and put in fridge. Then next day I got some out to snack on and noticed the inside of the SS was turning a greyish color around the high temp cheese that I put in it. Still smelt good, and tasted good. Day after that even more grey on inside of slices, still tastes and smells good. So my main question is, what is causing the grey color, just looks cosmeticaly bad to the eye. Has anyone seen this before?? My friend told be sometimes this happens but does not know why. I just finished a second 50lb batch, but used pork butts-and no grey on inside of them after slicing. Did the more pork fat cause some chemical issue or something??? Any comments much welcomed...