From fine food purveyor
marxfoods.com:
Best Long Term Truffle Storage: FreezingThough the results will not be as good as commercially preserved truffles, you can freeze truffles at home for long term storage.
Freeze the Truffles Plain: Freezing truffles is the most reliable way for a home chef to preserve them for up to six months. Vacuum packing before freezing is best, but if you don’t have a machine, place your truffles in a zip top bag with all the air pushed out or sucked out. Freezing the truffles separately will make it easier for you to use them one at a time later. Once frozen solid they can be consolidated into a single bag (with as little air as possible).
Once frozen, truffles are best cooked or grated from frozen rather than thawing first. If finely grated, the warmth of your food should thaw them.
Freeze the Truffles with Butter: You can also pre-grate the truffles and mix them with butter to make truffle butter, then freeze the butter.