Bests & Worsts Reviews from Amazon

My 10-year-old dog has eaten Canidae All Life Stages since the day I got him at 8 weeks old. With this latest bag (mixed in over several days with his old leftover ALS food, which was the first bag I ever got though Amazon) gave him soft poops and then diarrhea and a sore bloody bottom (sry to be explicit!). I even looked up a recall but saw no information. We did a bland diet (rice and boiled chicken) over a week, slowly adding kibble in as his BMs got better. Then he got sick again, and this time he also threw up. We did the bland diet again and slowly added in kibble, and he got sick again. Restarted the bland diet yesterday; this time, for now, I'm not adding anymore kibble.... Was this a bad bag? Is it coming from a bad source? Contamination? Poor/improper storage? I'm torn because I've always loved Canidae, but we may have to switch foods. Either way, this $60.00 @40 lbs of ALS has to go in the garbage.