How are expiration dates calculated on food items?
Generally, by how soon the products go bad regardless of a date.
Sometimes they cut it short, just to be safe, but even milk should be OK up to 7 days after the labeled expiration.
Most dates are voluntary and not double checked by another entity like the FDA (ever notice bread doesn’t usually need one? Because if it looks moldy, its probably expired) but some products do require one. Expiration dates, at least “use by”, “best if used by” and “sell by” mean what they say, sell or use by this date. But they really refer to a products freshness, not necessarily its safety.
Do Food Expiration Dates Really Matter? from WebMD.
Expiration dates are important for things like medicine, where you cannot tell how the chemicals have changed.
Most food doesn’t need experitation dates. Some food has “sell by” dates, which are different. They are meant to prevent fraud since you can’t taste/smell milk while it’s at the store. You can consume food past “sell by” as long as it smells ok.
How is it calculated? How do you think. Some guy stick his finger in the air and derives a number. There’s a million factors which affect how food spoils, and if you think a stamp will magically predict the future, you’re wrong.
What a dumb article.
“You open the fridge, drag out the cottage cheese, check for fur, and if there isn’t any, you say, “Honey? Will you sniff this?” This is not, however, the approved method of checking for freshness. The approved way lies in a voluntary system of labeling.”
Approved? By who? God? Funny how the article goes on to list a number of different stamps, NONE of which, by the article’s own admission, indicate anything about safety. A couple measure “peak quality.”
I think you can rest assured that any voluntary expiration date is going to err on the side of safety. There is a strong motivation not to piss off your customers by making them sick. If anything, they surely run a bit early, since that might lead to slightly increased sales.
I used to work at a company that manufactured nutritional supplements - not food, and not regulated by any agency. They used to calculate expiration dates by walking across the street to the Wal-Mart and seeing how far out their competitors’ expiration dates were. The guy who hired me put a stop to that and started a real program where they kept samples and tested them every few months to see how much of the active ingredient was still there.
I have used salad dressing that tasted great, only to later see that the use by date was two and a half years ago.