If you're asking how it survives the manufacturing process, we have discussed this before.... possibly something put on the outside of the food (enrobing) such as probiotics, vitamins, flavor enhancers, that aren't cooked on the kibble because cooking would destroy them. There should be something in place to ensure that those are safe, but if something goes awry there it could be a problem. Also, it doesn't matter if it was cooked through, if it runs across equipment that's contaminated after cooking and on the way into the bag, it can pick up bacteria.
I've got the dogs off kibble entirely, although I may go get a bag for the fosters I'm getting in a few days. Haven't really decided yet. Cats are still getting Taste of the Wild and Sput is getting Royal Canin's renal diet kibble, though. It's always a worry and I'm pretty tired of it.
susan
Fuzzy Wuzzy was a wabbit, Fuzzy Wuzzy had a dandelion habit! RIP little Wuz... don't go far.