Although frozen food or meats with gray or brown areas may look unappealing to eat, it is safe to eat these foods. The change in color on specific spots on food is the result of a chemical change that occurs when food is not wrapped correctly before storing it in the freezer.
The change in color that occurs because food is exposed to air and these grayish areas are dried out. To avoid this problem, it is recommended that air is completely removed from the plastic bag that the food or meat has been placed in prior to the bag being sealed.
If cooking food that has freezer burn, then it is simple to remove the affected area either before or after cooking it. However, if the frozen food is severely affected with freezer burn, then it may be wise to discard it for quality reasons.