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Expiration dates are bogus -- here's how to tell if food has gone bad

Erin Brodwin
Stocked refrigerator

Expiration dates are a scam.

The "sell by" dates on food products aren't a reliable means of telling whether or not a food is safe to eat, according to The National Resource Defence Council. Instead, expiration dates merely indicate when a food will reach its limits for something called "optimal quality," which again is based only on a rough estimate.

Fortunately, determining whether or not a food has gone bad is fairly straightforward, and requires just a small amount of know-how. Read on to find out if you should eat it or toss it.

Bread: It's mouldy -- even if the mould is just on one piece.

If you spot mould on one slice of bread, it's not safe to eat another slice -- even if there's no visible mould on the rest of the loaf. Toss it.

Because bread is porous, mould can spread easily throughout the loaf, so while a piece might look safe to eat, it could contain tiny mould spores.

If a bread has become hard and dry, but has no mould, it can probably still be used as bread crumbs or croutons, since mould needs moisture to grow.

Fresh fruit: Its texture has changed.

If your fruit has become mushy or grainy, it's probably a sign that you shouldn't eat it, according to the Greater Chicago Food Depository. Other warning signs that a fruit has gone bad include extreme discoloring, foul odours, or wrinkly, peeling-away skin.

Uncooked meat (not prepared to be served raw): It's become slimy or sticky.

Just because uncooked meat has changed colour doesn't mean it's gone bad, as the USDA points out. But if your meat is giving off a foul odor, appears slimy, or has a sticky or tacky feel, it's best to toss it.

Deli meat: It smells or changes texture.

If sliced deli meat like turkey, ham, or salami has a foul odor, throw it out; the smell typically indicates bacteria is growing inside, according to the folks at EatByDate.com. Also toss it if it has become slimy or hard, or if you notice any other change in texture. If you buy your meat fresh from the deli, make sure to eat it within three days.

Hummus: It tastes sour.

Growing up, I ate a lot of homemade hummus made with extra lemon, which gave it a slightly sour taste. Store-bought hummus typically doesn't have this zing to it, so if it starts to develop a sour taste, it's probably a sign that it's gone bad, say the folks at EatByDate.com.

Fresh vegetables: They turn yellow.

When most green vegetables begin to go bad, they start to lose their colour or turn yellow. This is often the case with broccoli and kale, for example, but may apply to other fresh veggies as well.

Still, some vegetables, such as celery or onion, can often be salvageable. Make sure you trim off the discolored portion and then try soaking it for 10-15 minutes in ice water to refresh it, the Greater Chicago Food Depository suggests.

Milk: It gets lumpy.

The easiest way to tell if milk has spoiled is by checking for changes in texture or consistency. Chunky or lumpy milk is almost assuredly bad, but you can also look out for things like discoloration or an unclean sour smell, which happens when lactic acid in the milk starts producing bacteria.

Yogurt: It puddles or grows mould.

Yogurt can last a surprisingly long time (about one to three weeks) when kept sealed, thanks to its live bacterial cultures, which act as a preservative. Once those cultures die, however, mould can begin to form. Look for a larger-than-normal amount of liquid puddling on the surface, a curdling texture near the bottom, and any sign of mould. These indicate the entire product has probably gone bad, say the folks at StillTasty.com.

Cheese: It smells like sour milk.

When it comes to cheese, perishability has a lot to do with the amount of moisture it contains.

Soft cheeses tend to spoil more quickly than hard or aged cheeses; similarly, if you spot mould in a soft cheese, you should toss the entire container. If you spot mould on a hard cheese, it's generally safe to cut off the moldy part and eat the rest, since the spores likely will not have spread throughout the cheese. Another good sign that a cheese has gone bad is a smell or taste of spoiled, sour milk. Fresh cheeses should not smell, chef Nora Singley writes in her 'Cheesemonger' blog for cooking site The Kitchn.

Uncooked seafood (not sushi): It starts to smell abnormally fishy.

Fish that's spoiled will typically have a slimy flesh with a thick, slippery coating. It will also start to have an intensified fishy smell that is stronger than it was when you first purchased it. Keep in mind that fresh fish should be eaten within 36 hours of the time you bought it.

Olive oil: It stops smelling like olives.

According to award-winning chef Marcus Samuelsson, 'Good olive oil should smell fragrant and fruity and taste like the olives it was made from,' he writes on his website. Oil that has gone bad will often smell like motor oil or glue, according to the Daily Meal.