When will it really expire?

Who determines the appropriate expiry date (or "expiration date" in American English) of a product (particularly a food item)? Have you ever wondered if your can of Coke will remain bubbly for another year as indicated on the expiry date? Well, I have. And I tried to dig up some info on this topic:

Nothing Simple about Food Dating, Expiration Dates or 'Use-By' Dates

The Truth Behind "Sell-By" Dates On Foods

Do Food Expiration Dates Really Matter?

Having researched these resources, it seems to me that the expiry dates tend to be on the conservative side. Are manufacturers erring on the side of caution or is that a legal requirement? Is there some kind of magic formula or is it just guesswork for different product types?

Digging further, I found this information on food product dating from the USDA's Food Safety and Inspection Service. Obviously, the part about federal law may not apply in your region. The information may also have expired - it was last modified back in 2007.

Related stuff:
The End of Moldy Strawberries? New iPhone App Tracks Food Freshness

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