As with any type of meat you need to make sure you use a high quality type freezer bag. If using the bags, make sure you have expressed all air from the bag. You could also invest in a vacuum packer.
The best way to preserve turtle meat for a long time is to clean it nicely and keep it in a airtight box in the refrigerator. But if you want to consume it within a weeks time than just apply salt and vinegar and keep it in the freezer. Afterwards thaw it and start cooking.
