If a pet owner is worried about ethoxyquin in pet foods then there are plenty of alternatives, in fact not many UK manufacturers continue to use ethoxyquin as an antioxidant these days.

Can't say I agree with the link to tartar build up, my guess is that this would be more down to poor quality food ingredients than an antioxidant.

Pedigree is a strange choice as a basic food if ingredients is an issue. Not sure what's in their basic tin, but their more upmarket pouches are not what you'd call great quality - typical ingredient list shows just 4% meat and 8% veg, animal derivatives, vegetable derivatives (probably including soya which is not that digestible, bakery waste products and not a lot else!

With Beef, Vegetables and Pasta Pouch: Meat and Animal Derivatives (Including Min. 4% Beef, Min. 4% Fresh Meat), Vegetables (Min. 4% Carrots, Min. 4% Peas), Bakery Products (Min. 4% Cooked Pasta), Cereals, Vegetable Protein Extracts, Derivatives Of Vegetable Origin, Oils And Fats, Minerals.