Took a tour of a Pepsi plant where they bottle Aquafina. It’s more for quality control. It’s difficult to eliminate 100% of bacteria and other things that can grow over time. Part of the testing is to put some of the water into a petri dish and accelerate growth, to see if there is anything nasty is in there. The water will most likely be fine after expiry but, in case there is something in there, the expiration date will provide a good idea of how long it will be safe to drink and to safeguard the company from liability.
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