Expiration dates on salt and water are funny and all, but expiration dates exist because capitalists would disguise spoiled food to maximize profit. And it takes an enforcement regime to make them care about their customer's health. Wasted food is still preferable to wasted life.
These regulations didn't fall out of a coconut tree.
In the US at least the dates are made up and inconsistent, like having best by, expires, and use by which all mean different things and are not regulated. For the most part they are about the taste and texture of the food, not food safety.
Except for infant formula, product dating is not required by federal regulations.
The expiration dates on things that do not spoil like salt were added by capitalists who want you to throw it out so you will buy more. It is abusing the voluntary made up and inconsistent date labeling capitalists came up with to weasel out of being regulated.
Other countries have regulations, but odds are that they don't apply to salt.
While that's true, most products have a "best by" date instead of an expiration. I worked for a company that bought items past that date from major retailers and resold it at.a discount.
A lot of these laws have to do with expected lifetime in "worst plausible storage conditions", like poorly sealed boxes and wrong temperature and humidity
Bet it has more to do with salt caking up and getting nasty appearing than anything else other than just a legal requirement. Also I think that’s a “best by” date not an expiration.
For some stupid shit reason, there is a legal limit for "best before" dates like that. You are not allowed to put a best before date that is more than IIRC three years after packaging.
Salt is the number one victim of this stupidity by far, if packaged properly it will still be usable salt a million years in the future.
But some other food items are definitely good after more than three years. Some tinned goods,
or rice, pasta, dried legumes, honey, sugar.
Seriously, the reason for the expiration date is pure salt draws moisture even though packaged and starts to cake. Most people don't want lumpy salt, thus the expiration date.
If enough humidity over time gets in there, the salt can start caking and forming larger crystal clumps. However, the salt itself isn't damaged by that process and will work fine if broken back up and used in the quality you need.
A best by date here would be a notice from the manufacturer that the product should be shelf stable at least that long before "degrading".