A recent piece bv Dr. Micheal Fox (DVM) is an edifying read -it seems that the rat poison may indicate the presence of of transgenic (GM) rice, wheat and corn - products which are totally unfit for human or animal consumption, at least to my mind.

LARGEST PET FOOD RECALL EVER:FULL INQUIRY CALLED FOR: AND ACCOUNTABILITY
By Michael W. Fox B.Vet.Med., Ph.D., D.Sc. M.R.C.V.S.
May 10, 2007
http://tedeboy.tripod.com/drmichaelwfox/id74.html