Err ... I'm not so sure.
It's a bit like milk ... if you can smell it, you probably don't want to drink it.
I haven't used DT's in a while, but I do remember giving it a sniff test once in a while. It definitely smells bad once it's gone bad. When it wasn't bad, well, it didn't smell like roses, but, umm ... well, "rank fart" is not what I would use to describe it at that point.
Hate to say it but I think it might be toast .... sorry!