Agree, it's fine, unless you are adding tons of it. We generally say no more than 10% of your pile should be any one ingredient (like citrus pulp). If you are sticking to that principle, the acid will get balanced out with other stuff.
Pineapple's I put the skin and tops in mine for 2 years i always have 1 to eat actually the last one i bought was very light color inside hard as a rock to eat.This time of year usually they turn bad very fast with the heat on inside the house. I have been eating the since i was a young child. I lived in Thailand and Puerto Rico as a child