Just recently read this and thought others might enjoy reading this educational article.
The dog food I use has probiotics sprayed on the kibble after processing so I don't think that is the same thing they are talking about. They are discussing kibble where probiotics are added and cooked with the rest of the kibble. That is my understanding anyway.
Just another bit of info, beet pulp is a prebiotic.
"Surprising: The Pet Probiotics that are a Total Waste of Your Money…
By Dr. Becker
If you're confused by the difference between prebiotics and probiotics, you're not alone.
One of the differences is that prebiotics feed intestinal bacteria, while probiotics are one type of those bacteria -- the good type.
Prebiotics are billed as feeding only beneficial bugs in the gut, but research indicates they feed both good and bad microorganisms.
For Pets with GI Conditions, Prebiotics Are a Bad Idea
For a dog or cat with a very fit digestive tract, prebiotics probably won't do any harm. But many pets today have GI conditions like IBD, IBS, leaky gut, small intestinal bacterial overgrowth (SIBO) and other issues. The good to bad bacteria ratio in their GI tract is out of whack, and the last thing we want to do is feed pathogenic bacteria with prebiotics.
That's why I always warn against prebiotics for pets with any type of gastrointestinal dysfunction.