Where can one find specific information on food labeling?

All those terms usually mean the same thing and the manufacturer wants you to stop using the product at that point. They often do have a margin of error built in, but how long something remains good for varies by the type of food, how it's packaged, and how it was stored. For example, if I buy a gallon of milk and put it in the coldest area of my fridge, it's still probably going to be good a week after its expiration date. If I put it anywhere else in my fridge, it usually dies close to the printed date. Things like eggs can be good for months after their expiration date. The only way you'll know if they're still good is to crack one open and observe its appearance and smell. In most cases, if it still looks and smells ok, it probably is.

Actually... here at least the terms have very different and supposedly clear meaning.. Use by means you should use it by that date or it can be unsafe... Best before means that the product will be safe and not in any way harmful but may loose quality in terms of taste, texture or nutritional value.. but it won't harm you...

Actually... here at least the terms have very different and supposedly clear meaning.. Use by means you should use it by that date or it can be unsafe... Best before means that the product will be safe and not in any way harmful but may loose quality in terms of taste, texture or nutritional value.. but it won't harm you...

I was listening to a dietician on NPR and she stated the expiration dates are meaningless on sealed products. She said she ate yoghurt that had expired a year before. A can of soup or beans etc should last for years.

on the net

Only on infant formula does the date code have any meaning in all 50-States and the several territories of the US. 20-States do have their own dating laws for foods, mostly dairy, with either a "sell-by" date or a "use by" date. But otherwise those codes are largely meaningless.

In States that do have that "sell by" code requirement stores may not sell dairy items after that date. Dairy products are considered to be good and safe for consumption for 5-days after the "sell-by" date. If no meaningful statutes are in place you're State you're pretty much on your own. But be sure to check with your State's Department of Agriculture for information specific to your State. (Most nationally distributed foods used to follow the Pennsylvania Department of Agriculture rules as they were the most stringent at one time, don't know if that's still the case though.) Here's a link to a story on the subject. 

https://www.businessinsider.com/what-sell-by-date-means-on-food-packages-2013-9

For items that require refrigeration we pretty much follow the date codes with heavy reliance on the old schnoz as the product nears that date. Be extra cautious in the meat department. I know for a fact that some grocers/butchers will "renew" the date code on meats like hamburger by simply re-grinding it to get rid of the gray color as most hamburger is made from frozen beef anyhow. They can safely get away with that once, but no more than that.

For canned goods so long as the can is not bulged (or the "button" on the lid of a jar hasn't "popped") we consider it to be OK so long as it passes the smell test. Same for dried goods like beans and noodles, The quality of those items drops off to the disgusting level long before they become dangerous to consume.