I'm not sure where you heard that about the ro water getting contaminated but it's not true. If you purchase an ro system or any water filtration unit, including the one you're looking at, you need to store the water after mixing in salt, and buffering if needed, for at least 24 hours before using it. There are a few reasons for this, including allowing the oxygen/carbon dioxide levels to equalise and allowing the salt to mix thoroughly with the water. During this time you need to keep the container the water is in covered to prevent dust settling on the water and contaminating it. This may be where the contamination story came from. To summarise, the water will not contaminate on exposure to air and actually needs to be aerated in order to equalise the o2/co2 levels.
Shark.