From the website greenshavings.com :
Green Shavings are specially treated with a common food additive to inhibit the growth of funky stuff. The organic active ingredient, Potassium Sorbate, is safe, tasteless and odorless. It's widely used as a mold, yeast and bacterial inhibitor and as a fungistatic agent in cheese, drinks, cosmetics, wines and pharmaceuticals.
Once the shavings are treated, they are colored green to identify them. The color is fixed and won't rub off or run off when the shavings get wet. Besides protecting your horse, they also add color to your barn and make your horse look great.
Let me know what y'all think!!