can olive oil go bad?

I was refilling my smaller olive oil bottle from one of those big canisters of EVOO that I bought at the supermarket. The canister was almost out and when I poured it, there were some black threads inside the oil. I immediately stopped using it and am not sure what that stuff was. It's never happened before. Any ideas?

Re: can olive oil go bad?

Yes.. it can go rancid. I've never really noticed anything IN the oil - black or otherwise - but the taste and smell go off - usually after too much light.

I used to keep my oil in a clear glass container on the windowsill.. learned quickly that it was better served in a darker glass bottle in the cabinet!

If there is any doubt.. throw it out.