What do Food Expiration Dates Mean?

So we just returned from vacation. Of course, now there is no food in the house or at least very little. One of my least favorite tasks when returning from any trip is opening the fridge. We got in very late or very early depending on you point of view. And at 8:00 this morning I still haven't peered in the fridge. I purged quite a bit before we left like milk, yogurt, meats, veggies and other things that I expect wouldn't make it through the week. I hoped our pet sitter would eat the watermelon, but instead found that it had multiplied and we now have two. How long does a watermelon last anyway? How long does any food item last? If it doesn't smell, ooze or get fuzzy is it still good? And what about expiration dates? Is a jar of un-opened pickles history if the "use by" date has passed? Are pickles good for breakfast?

photo by Whit Balance

Food, like everything else has it's own confusing lycos of terminology. And each little word change can vastly change the answer to the question "can I eat this?" So for your information here are a few definitions:

Expiration Date refers to the last date a food should be eaten or used. Last means last -- proceed at your own risk.
"Sell by" date is a suggestion to the store for how long to display the product for sale. It's not a mandate. It's more of a notice of quality as deemed by freshness, taste, and consistency not to be confused with spoiling potential. Food is still edible past the "sell by" date. Psst-If you want the freshest items reach into the back of the shelf and check the date.
"Best if used by (or before)" date again refers to quality, not safety.
"Born on" dates orginated with beer. And its not just a marketing trick. Beer really can lose flavor after about 3 months. Clear bottles are especially subject to microorganism growth from sun exposure.
"Guaranteed fresh" dates are often found on baked goods. After this date they become more than day old bread and won't be as fresh. But even before you see green fuzzies baked goods can develope a white powder--also mold.
"Use by" date is the last date recommended for the use of the product while at peak quality. Not too different from "Best if Used by".
"Pack" date is used on canned or packaged goods. This one gets me because I always thought it was an expiration date. Canned goods won't always use the lingo they may just put a code on the can that includes a date. It can be month-day-year-MMDDYY. Or the manufacturer could use the Julian calendar. January would then be 001-0031 and December 334-365. Or whatever system they choose. Canners mainly use the code to identify the batch. If a batch problem was discovered the code helps them recall or pull the product.

I gathered all of these definitions from a variety of sources WebMD, KATU TV (Portland, OR), and Business Week. But it's interesting to note that the FDA only requires expiration dates for baby food. All other food items are voluntary. Still I'm not eating those pickles for breakfast.