I had a vet tell me that dry dog food was less prone to spoilage than wet or canned. Furthermore, that vet also told me that only one brand had been tested. When I have asked about that, any vet I have asked has agreed with that, except for that brand developed by Canadian Veterinarians. But you can't take this last brand across the border per current regulations. Hence, I have gone away from it, more's the pity.
:C