You will find that in our food, the colour is more red towards the middle of the pack. This is because the contents have been vacuum packed and the blood therefore migrates towards the middle. No preservatives are added to our dog food for preservation. It's vacuum packed and frozen straight after the mincing and mixing process.
Supermarket meat has been through a process of blasting. Fresh meat may be displayed in ‘modified atmosphere’ packs with harmless gases inside that delay natural discoloration and in so doing, keeps it looking more red than it would naturally.
Read the below link- it's very interesting. Your local butcher for you and your dog is always best. It's fresh and not tampered with. In the UK and Europe, Carbon Monoxide gas has been banned for use in this process.