Sorry for the blitz post, but patch14 commented on shelf life of foods and I couldn't put the attached photo up to reply.
The picture is of a contraband muffin we can call 'Mr. Muff".
Written on the bottom of paper cup is the date (7/3/12) I retired him as a semi gnawed piece of contraband, confiscated (surreptitiously) after a kids' party, and for the past two months he has sulked in a kitchen cupboard. However, 'age has not withered nor custom staled' (him) as the bard would have it!
You could try this yourself with 'Mr. Kipling' to see just how long a piece of confectionary will glower, but not fall apart, whilst being attacked by the airborne pathogens it valiantly repels.
Now, I cannot tell you if this experiment has any relevance to what my mother used to bake as the pies and cakes she produced were never around for that long (hot was the best). I guess it might have been quite a while, as her cakes and pies were full of saturated fat (butter and lard extends shelf life, hydrogenated fat does the same but is cheaper!)
I'll occasionally update his progress.