I am really opposed to using preservatives, especially ethoxyquin as I keep hearing about the bad side effects. I try to avoid my human kids having colours and preservatives and the same goes for my four legged mates. 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.