Preservation was an alteration/necromancy spell that preserved uncooked food or meat.
By casting this spell, a mage maintained food or meat in a state of relative freshness. In the case of animal flesh, it was kept as if creature had just recently been killed.
This spell could be used to prevent the decay of a humanoid body, in preparation for the individual to be resurrected (in a manner similar to gentle repose). If cast on a zombie, lich or similar undead being, it prevented further decay of their body.
This spell required verbal, somatic and material components in its casting, the latter of which was a single pinch of salt.