What is the white paste found in canned black olives?

Every once in a while I open a can of olives to find that there is a white paste on the inside of the can and little pieces of it on the olives themselves. I can’t find out online what it is. I’ve read everything from bacteria, to naturally occurring yeast. What is it? And, is it safe to eat?
Thanks!
I’ve heard that it could be oil before, but wouldn’t it melt under hot water? This stuff doesn’t.