Zinc oxide is the metal zinc that has been oxidized. The chemical formula is ZnO, 1 zinc atom and 1 oxygen atom held together by an ionic bond. Zinc oxide does occur in nature as the mineral zincite, but it is quite rare and commercially unavailable.
I have done a few stool samples in my time and have always just stored them in the fridge, until the next day to take them into the docs. Good luck hun I hope they get it sorted.
Here are their guidelines for how long you can keep opened containers of common condiments (commercially produced, not homemade) in your refrigerator: 1  BBQ Sauce: 4 months. 2  Capers: 1 year (brined). 3  Horseradish: 3-4 months (prepared).