green tom chutney how long will it keep?

When they moved, my mother had some on the shelf that was 12 years old, sealed in plastic lidded screwtop coffee jars.  She gave it to us and we ate it.  It was good, matured and perhaps a bit smoother in texture and taste than ours from 3 years ago.   No-body got ill, grew two heads or anything.

And if there was a resulting mental health problem - no-one noticed!  But then they wouldnt!!