You have to be careful not to over-generalise about pet food companies and the various products out there. Yes, many do use animal derivatives which some would choose to avoid, but there's a whole host of products now using the more acceptable meat meal (dried meat) such as Burns, Arden Grange, Pets at Home brand, Skinners, Pascoes, gelert, James Wellbeloved etc etc and who also use natural preservatives - in fact the big companies are switching to these as well.

Pets at Home have a good range of natural foods under their own brand and at a good price (I feed their Wainwrights Light recipe which is naturally preserved, does not use animal byproducts and costs £14 LESS than an equivalent 15kg bag of Burns which I used to feed. My dog is looking much better on it as well, as lots of dogs go too thin on Burns).

For info on ingredients used in the UK (rather than the scare stories of US companies check out www.pet-food-choice.co.uk/pet_food_ingredients.htm