This is the same product used by dairy farms to rinse their stainless steel bulk tanks and equipment.  It is a safe product when used responsibly. 
This product will help protect your stainless steel from the buildup of calcium deposits and milkstone.

Use 1 tsp. (5ml) in 1 gal.(3.75L) warm water (100f/37.7c) and allow to rest for 10 minutes to prevent milkstone buildup and spotting.

Warning: Contains phosphoric acid (75% solution) active ingredient(56.33%).  Other ingredients: Surfactants, Dye, Water 43.67%)
Use rubber gloves if this solution is irritating to your skin.  Protect your eyes and minimize splashing.