Yesterday at work, someone pulled a yogurt container out of the frig. It was an opened container of Plain non-fat yogurt that had been used for a veggie dip some time ago. The 'sell by' date was 12/22/10.
So, the question was "is it OK to eat?"
I said that as long as yogurt isn't moldy, it's safe to eat. It's already sort of "sour", so it doesn't turn bad the way that milk does. It didn't smell "off", it didn't taste "off", so I thought it was fine. I even thought I'd bring it home and use it.
Others in my office were horrified! Eating past date dairy is apparently one of the most life-threatening things you can do. We ended up throwing it out - mostly because I wasn't sure enough of my position to stand up to the collective horror.
What's the consensus SE'ers? Is past dated yogurt safe? How can you tell if yogurt is "bad"?