Investigations are ongoing to determine why human illness, especially among infants, is associated with dry pet food. Factors under investigation include handling and storage of dry pet food, hand-washing practices, exposure of children to dry pet food, and location in the home where pets are fed.
Salmonella Schwarzengrund Outbreak Investigation | CDC Salmonella
The whole subject of pet food being contaminated is still being studied and it doesn't look like too much has changed since this article. It's hard to say.