A good friend brought this topic to my attention. Apparently many of the commercial grade dog treats contain glycerin; it is used as a filler, adds to the weight of the item, inhibits mold growth and makes the treat softer.
The catcher is that this chemical can range from mildly irritating to potentially fatal in dogs, depending on where it is derived from. Many pet food makers are calling it “natural” when it is derived from soap versus derived from biodiesel which contains other harmful chemicals such as methanol (wood alcohol) and a hefty amount of sodium.
It is hard to determine where this glycerin was taken from and that is why owners are starting to question this humectant.
I’ve attached a few good links that delve into this topic and I hope you all find this helpful. I did!
It’s a bit technical, trying starting halfway down as it addresses the types of glycerin in pet foods.
http://www.petfoodindustry.com/Sub_Level_-_News/45418.html
-Awesome Tails