How long does it really take for food to go bad?
Many consumers call the date printed on store-bought food an "expiration date" and use it as the gospel as to whether that food is safe to eat or not. Unfortunately, for the most part, those dates have nothing to do with expiration, and many foods people call "expired" are safe to eat weeks or months after that date.
See, food producers don't have to put any dates at all on their food (unless we're talking baby food and formula, in which case, those dates are federally mandated, and you should never serve food past that date). So, while some packages still have an expiration date on them, others have entirely different dates that are there to let you know when food is at its freshest and when stores should get it off the shelf.
We're not saying you should eat foods well past their date, but if you know what the dates mean, then you can eat food longer than you maybe thought.
Reading dates on a package
While there may be some parts of commercial packaging that are intentionally misleading (like 7UP being "all natural"), dates are straightforward if you know what to look for. Again, the only true expiration date appears on baby food and formula. Just about everything else is a "sell by" date (which tells the store to sell the product by that date so that the product will be at its freshest), "best used by" date (which tells you when to use the product for maximum quality) or "born on" or packaging date (so you know how old your beer… er, food… is).
Each of these dates is useful, but rarely does it mean that once the date has past the food is bad. Each food has its own shelf life after that date has past.
While Americans love to refrigerate their eggs, they're actually fairly spoil-proof and can sit out for a while before they go bad. WebMd states that, when stored in a cool, dry place, eggs can last up to five weeks before going bad. If you're concerned they've gone bad, the good news is that the lovely smell of sulfur will give you your first clue.
Surprisingly, mustard, mayonnaise and ketchup can all last a long time unopened and months opened. Who knows? Maybe a jar of mayo you buy today will mature over time and be even better in 10 years?
As long as the can isn't dented (which could allow in outside bugs) or bulging (due to bacteria growth), canned goods have a shelf life of at least 18 months. Some inacidic foods can last years with going bad.
Milk is good for about a week after its "sell by" date as long as little chunkies don't form.
Meat and fish
Meat spoilage will vary based on type, and quite frankly, it's tough to know how long meat has sat on a shelf before sale. Still, for delicate meats like fish and chicken, you should pretty much cook it and serve it in 24 hours. For red meat, you can have a few days to serve it. Of course, meat that smells or that has a funny color is bad no matter how old.
Bread will go "bad" after a day or so, but it is still edible as long as it's not growing mold. Sure, most bread can be used as a hockey puck or baseball bat after a day or two, but you can eat it as long as it's not green.
But above all else, remember to trust your senses
No matter what we said above, trust your nose, your eyes, your tongue and your gut (both figuratively and literally). If a food looks wrong, has a powerfully bad odor (and isn't blue cheese), or if the texture is wrong, then toss it. There's no reason to make yourself sick over a bottle of mustard or a piece of meat that turned before its time.