Just as a point of interest, I had a bag of Canidae about a year ago that had that white grit all over the kibble......when I called them, I said it looked like somebody had sprinkled salt over it. I was told it was due to breakage during shipping......didn't buy that one as kibble isn't white. Brought it back to the store & never bought it again.
Somebody shortly after that found the same white grit in another brand of kibble but I can't remember now what it was. I do remember when they called the company, they were told to throw it out & to disinfect the container before they put more food in it (where they were storing the kibble). That sure didn't make me feel too good about what they thought that white grit may be. I'm not sure right now who the poster was but if they read this, they can tell you what brand it was.
Too bad about my failing memory, huh?