I heard in the news that arsenic can be linked to certain types of cancer. Still if there are high concentrations of arsenic in rice, it does not makes sense to feed it to your dog everyday.
http://www.wired.com/wiredscience/2012/09/arsenic-and-rice-yes-again/?utm_medium=referral&utm_source=pulsenews
FDA Article on Pet Food Labels
-
This was posted to another list I am on
http://www.fda.gov/AnimalVeterinary/NewsEvents/FDAVeterinarianNewsletter/ucm130726.htm