The oldest items in my fridge, actually aren't food and you really REALLY wouldn't want to eat/drink them. One is a bottle of ethyl acetate, kept in the fridge because of the shitty plastic it came in, to prevent evaporation through the walls of the bottle, the other is a container full of ergot sclerotia for culture.
Ergot (Claviceps purpurea, a parasitic fungus of grasses and grains) is highly toxic, the alkaloids in there like ergotamine though, are useful, ergotamine is used sometimes to treat migraine, because its a powerful vasoconstrictor. And I forget which one now but another ergot alkaloid is used for its vasoconstrictive properties to prevent or treat hemorrhages after birth of children, and as an oxytocic.
Hydrolyzed carefully with base though, lysergic acid can be obtained. Although breeding a productive, stable strain for culture, using various mutagenic chemicals is a nasty task owing to the fact that they will mess up the biotechnician's DNA as easily as it will the ergot cultures.
And a LOT of work needs to go in, I'm barely started. Estimated time to success is in the years, but I've spent 2-3 years just reading and doing research, as well as buying a hardcopy of the book 'the genus claviceps', managed to get one on amazon for about $40, rather than the couple of hundred £ GBP that many sellers of the book were asking. And its a goldmine of information, an absolute goldmine of truly indispensable research. Plus interesting bedtime reading.
But were someone to eat those sclerotia, chances are their extremities would become gangrenous and rot off, fingers, ears, dicks, noses, toes, hands, feet etc. Quite a lot of bio work and chemistry needs to go in to any productivity and anything harvested needs a lot more work to turn it into psychedelics, such as lysergic acid dimethylazetidide, which is more potent than LSD by weight (!) or the morpholide, less potent by weight but meant to be smoother. That and a sep funnel containing an amide of piperazine, the propionamide IIRC suspended in a little xylene.
Yup...its best and healthiest to look carefully at exactly what is being taken out of the fridge before consuming anything. Because hades only knows what'll be in there at the time:P