I've also been told that ethoxyquin has to be labeled as a poison and that demonstrates how toxic the stuff is. Preservatives are not bad. They are for the owner's visual sense, not the dog's. Preservatives are good. Let me repeat.
Preservatives are good.
While some vitamins may be deactivated in the processing, they are added back in. When used with fresh meats, etc. If you think feeding bacteria and mold to your dog is better than not, then more power to you. However, this distinction generally doesn't come to us when we discriminate against foods with preservatives. Obviously, if one can afford the time, and money, to go to the store every day, prepare fresh meals for your dog, this would be ideal.