I have some 1/2 gal Ball jars and want to use them to store some grain, powdered milk, beans and other foods. My question is does anyone have an idea how much oxygen would be left after using a food saver jar adapter to pull a vacuum? I have already sealed some powdered milk and that worked just fine but I have read that you need to get the oxygen level to below 1% for over 1 week to kill off the critters. I have no idea what remains in the jar after the vacuum shuts off. Any input from anyone?