The TNG Tech Manual says there's an inner lining of some magical substance (ala dilithium) within each antimatter pod that produces a magnetic containment field. It might be a case that even if the ship loses all power, the pods won't rupture unless they are physically damaged (say during a battle) and the pods' containment fields starts to decay. If you're lucky, you might have time to eject the pods, if not...
Hey, don't they have room temp. superconductors in Trek's time?
And isn't it true that once you set up an electric current in a superconductor - say, a superconducting ring or coil - doesn't it pretty much go on forever?
And doesn't an electric current circulating through a conducting
coil of wire, produce an magnetic field.
So...if you wrapped the anti-matter pods with superconducting rings or looped coils...wouldn't you pretty much have something that would generate a magnetic field with little need for more electricity to be applied.
Of course, in the real word - the coil would lose power eventually, as no conductor is perfect - electricity would *leak* out do to quantum effects, subtle imperfections, etc...and wouldn't any "work" the magnetic field did cause a subtle loss of energy? ('Work', such as repelling and bending the path of the charged anti-matter particles?)
But if you had room-temp or even high-temp superconducting coils wrapped around the storage pods or whatever, you would have a pretty low-maintenance way of storing anti-matter in a self-sustaining magnetic field that would work for a while, at least, with little or *almost* no power? (And if you did other tricks such as super-cooling the antimatter and compressing it *somehow* to it stayed cold, like someone suggested earlier...)
Just a thought.