As Wokka says. Freezer burn is caused by the evaporation of water from the item, directly as ice to vapour, without going through the liquid (water) stage. The vapour then recondenses as ice on something cooler in the freezer. Many human foods are 'freeze dried' - placed under vacuum and kept frozen until most of the water has been removed - they can then be packed in airtight containers and stored without freezing, for long periods of time. Because freeze-dried food is lightweight (no water) and easily stored, it is used by astronauts and other travellers who might need food for long periods of time but can't have much weight. Surprise Peas, coffee powder, and other foods in the supermarket are prepared this way. If your freezer is operating at a suitably low temperature, it won't affect the food value of the item, but as has been pointed out, the item may become dryish and brittle. Domestic vacuum packing devices greatly reduce the incidence of freezer burn - I've used pink mice that have been frozen for 2 1/2 years in a vac bag, and they have been just as good as fresh ones.