Something nasty in the cupboard

For a long time now a strange brown sludge has been dripping down the wall in my kitchen, and rendering a large patch of the topmost store cupboard (the one I can't see into) disgustingly sticky.   I cleaned it up as best I could, from time to time.  I had always assumed that it was an accretion of the sticky brown gunk that seems to coalesce from Chinese cooking oil - although it was a mystery as to why there should be so damn much of it in this one spot in the kitchen.   But no.   When I was having a thorough clean-out the other day, I discovered a large can of Del Monte peach halves on that shelf.  A can that, from the weight of it, appeared to be nearly empty; but it had never been opened.  And it made a strange, dusty rattle when I shook it. Of course, out of curiosity, I opened it up.  Inside, there were was about a one-inch layer of fine, dry-ish silt, and two or three small sticky brown lumps.  Nothing that even vaguely resembled a peach.   So, that's what the nasty, sticky mess was.  The peaches had somehow decomposed in a way which caramelized them.  And this caramel-like goo had somehow escaped from the tin (god knows how - no visible holes at all).     Any scientists out there who would like to try to explain this one for me?    Was there some kind of microscopic hole in the can?  How could this happen?  How could the thick goo escape through such a tiny aperture?  What kind of bacterial action could bring about this remarkable transformation of my peaches?   I really would like to know.