When does it go bad?

When to keep and when to toss your favorite foods.
© MSN Healthy Living // © MSN Health

Do you know how long to hold onto the food currently sitting in your fridge? In honor of Clean Your Refrigerator Day, here is a guide to the foods that should go and the ones that can be kept around a little bit longer.

--By Sally Wadkya for MSN Healthy Living

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Ever wonder why that wonderful fresh loaf you bought at the bakery grows mold in a matter of days, while the grocery store variety can last for several weeks? The difference is preservatives, which can greatly extend the shelf life of mass-produced bread. But you also play a role in how long bread survives in your kitchen. Too much of this creates a prime environment for bread to mold.

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When it comes to its edible lifespan, not all cheese is created equal. Experts say hard cheeses (like this kind) can literally last for years, but soft cheeses (like this tasty one) will mold much sooner. The difference is in the amount of moisture in the cheese — ones with more moisture grow mold much faster.

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There are two good guidelines to follow when trying to decide if the milk in your fridge is spoiled: Check the date on the carton and give it a sniff. If milk smells sour, chances are it won't taste very good in your coffee or cereal. There's no difference in the lifespan between organic and non-organic milk, but the amount of this in the milk can impact its shelf life.

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Keeping eggs safe means keeping them cool. Make sure you purchase them from a refrigerated case and store them at home — in their carton — in the refrigerator. You can also use a specific stamp that's usually on the carton as your safe-eating guide.

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Cold cuts

If you buy your lunch meats freshly sliced from the deli counter, you'll want to make sure to eat them within three to five days (and keep them cool in the fridge during that time). An unopened package of turkey, ham, bologna, salami or other deli meat can be stored longer (how much longer?). But once you break that factory seal, those meats will need to find their way onto a sandwich soon.

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Since mayonnaise contains this ingredient, it's not made to last forever. But when it's commercially manufactured, the condiment also contains ingredients to help preserve it and extend its shelf (and fridge) life. Besides reading the "best by" date, a good way to determine when mayo is bad is to follow your nose. If it smells sour, it's likely past its prime.

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When you buy a head of lettuce at the store, it should keep, intact, for a few weeks. But once you open up the head and cut up the lettuce, it will start to spoil faster. Leaf lettuces that are sold in bags or containers can last longer than a head you cut up yourself because they are better protected from oxygen (and what else?).

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Fresh meat and poultry

As a general rule, you should plan to use or freeze fresh meats within days of purchasing them. The good news is that meat keeps much longer in the freezer. If you don't think you'll have a chance to cook what you've bought, toss it in the freezer and know that you can safely defrost and cook it any time over the next year.

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