USA Legislation for Freezing Temperature

I am seeking to confirm the FDA and USDA-FSIS regulatory reference for freezing product.  Specifically, for cold storage of frozen product.  Product is Ready to Cook (raw) but is being received at the warehouse already solidly frozen.  I know the storage conditions must be set at -18C/0F but I am not finding this anywhere in the regulation.  I found the temperature and time requirements to freeze (from raw, cooking and partial cooking) but not cold storage until shipping to the customer. 

Thanks in advance for any assistance.