From Mental Floss:
A 1987 NJ state law required all food products sold there to display an expiration date of two years or less from the date of manufacture. Labeling, separating and shipping batches of expiration-dated water to the Garden State seemed a little inefficient to bottled water producers, so most of them simply started giving every bottle a two-year expiration date, no matter where it was going.
Now, the U.S. Food and Drug Administration has never established or suggested a limitation on the shelf life of bottled water as long as it’s produced in accordance with regulations and the bottle remains properly sealed. But the expiration date has been an industry norm for so long that many producers have just kept it on there.
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