My dog and her pups have a pink/rust looking tint on their front paws & muzzles that isn't coming off. Is it bacteria? Have you heard of this? Is it harmful?

Hello Ed and Cindy: I've just discovered your site & I love all the info you provide. It's both educational & reaffirming.

Q: I've bred my two Pembroke Corgis. I've noticed in the past that they tend to get food allergies which cause a red belly & pimples under their muzzle. So, I feed them all natural dog food from the feed store. This has solved the problem. Since being bred, my female has been on the same brand of food but we are offering puppy food & vitamins for added nutrition. The pups are now 2 weeks old. I noticed 4 days ago that overnight the pups had a pink/rust looking tint on just their front paws & around their muzzle but only on their fur. I wiped them with puppy cleaning wipes and it does not come off. I noticed today that mamma has that same coloring on her belly and around her nipples, which I assume is where the pups are getting it. Her's also does not wipe off. Is the reddish tint rubbing off on the puppies. Is it bacteria? Have you heard of this? Is it harmful? Thank you!