The Cold, Hard Facts: How Your Refrigerator Is a Bacterial Cesspool

As gross as curdled milk might be, it probably won't make you sick. That's because the molds, yeasts and bacteria that cause spoilage (i.e., food with an odd odor, flavor or texture) simply make foods look and taste unappetizing. On the flip side, pathogens in food, such as E. coli, can make you very sick, but they don't make food taste, smell or look bad in any way, according to the Department of Health and Human Services (HHS). The fact that pathogens are sometimes undetectable makes them all the more dangerous.

Every year in the United States, more than 250 foodborne diseases make 48 million of us ill, leading to 128,000 hospitalizations and 3,000 deaths, according to the CDC. Many of these bugs are already present on the foods we purchase at the store, says the USDA; but less-than-ideal storage conditions in our refrigerators allow them to contaminate other foods and grow out of control to the point that they can make you sick. The good news is that many cases of foodborne illness are completely preventable. Here are 11 dangerous fridge mistakes that might make you ill and how to set them right.

Almost half of all American homes have a too-warm refrigerator, according to the Partnership for Food Safety Education. "This is the most important thing for consumers to remember about food safety," says Shelley Feist, the partnership's executive director. "There's a big difference between 40 and 44 degrees." A fridge that's set anywhere above 40 degrees Fahrenheit allows bacteria to grow. Although a chillier environment won't kill bacteria, it does keep it from multiplying to the point that it can make you sick, Feist explains. She suggests keeping a separate thermometer in your refrigerator as a safety check, especially if your fridge doesn't have a digital temperature display.

Up Next: Here's why you should be mindful of those leftovers.

Got leftovers? While it's noble to avoid food waste, especially since we throw away a third of the food we buy, the meals you prep at home (or take home from a restaurant) don't last forever. Leftovers don't contain the same preservatives as commercial food and aren't industrially packaged to prevent spoilage and contamination. The longer they're in your fridge, the more chances that bugs like listeria have a chance to grow, says the CDC. Toss or freeze homemade food within four days, advises Feist. And another word to the wise, says Feist: Toss any leftovers that have been sitting out at a family dinner or buffet table for longer than two hours.

Up Next: This is how you can get sick from opened food packages.

You may have heard that the "best by" and the "use by" dates are set by the FDA to maximize the quality of the food. That rule no longer applies to food once the wrapper has come off. "Even if a date stamp is far into the future, bacteria have the opportunity to multiply after the packaging is open," explains Feist. According to the HHS, lunch meats, chicken, egg, tuna salad, macaroni salad and fresh steaks should be eaten within three to five days after the packaging is opened. Cooked meat or poultry should be eaten within three to four days. Feist notes that condiments typically contain preservatives that keep bacteria from multiplying, so they will last much longer.

Up Next: Storing raw meat in the wrong place can be dangerous.

Because raw meat, poultry, seafood and eggs are the common culprits behind foodborne illnesses, keep them separate from all other foods in your fridge and on a lower shelf so juices don't spill and cross-contaminate other foods. "Bacteria can survive for quite a long time on your fridge shelf," says Feist. That means you should keep meat and poultry in its packaging until you cook it, thaw it in a dish with an edge if it's frozen and store leftovers in a container with a lid.

Up Next: Here's why washing produce before storing it can make you sick.

While you might be tempted to wash your fruits and veggies before storing them in your fridge, that's not a good idea. "If moisture remains on the produce, it speeds up the decay. Plus, your fridge might be contaminated, so you'll need to wash anything you are going to eat before using it anyway," says Feist. This is especially the case for leafy greens and berries, which tend to take longer to dry. Instead, rinse produce thoroughly just before you prepare it, blotting it dry with a paper towel or clean cloth.

Up Next: Do not keep this food in your refrigerator door.

Compared to the back of your fridge, the doors on your appliance are a whole lot warmer, says the USDA. One study by Tennessee State University researchers found that more than 66 percent of fridge doors had a temperature above 40 degrees Fahrenheit for more than eight hours a day. To be on the safe side, refrigerate eggs, meat and produce in their original packaging in the center of the refrigerator. "Milk and cheese are highly pasteurized, so they have a fairly long shelf life," says Feist. That means these and processed packaged foods like condiments are not as worrisome if they're stored in the door.

Up Next: Think before you overstuff your fridge.

Cramming every last inch of your fridge with food means it has to work harder to keep air circulating and the temperature down. "That may make it more difficult, if not impossible, for your fridge to reach 40 degrees F or below," says Feist. If you can't see any empty space in your fridge, it's time to purge opened foods that you know you're not going to use. Remember, too, that foods that aren't refrigerated at the store, like condiments and sodas, don't need to be refrigerated at home until they're opened.

Up Next: This is how root vegetables can may you sick.

With all of the talk about the bacteria and parasites on meat contaminating other foods, it might seem like the last thing you need to worry about is the contents of your veggie drawer. And while fresh produce isn't nearly as much of a health risk, root veggies like potatoes and carrots can be covered in dirt hiding E. coli. So instead of letting potatoes scatter across your crisper, keep those veggies in the bag from the store. To be extra cautious and avoid contaminating other produce, brush off any dirt you do see on your veggies before you put them away, suggests Feist.

Up Next: Avoiding a thorough cleaning of your refrigerator? Not so fast.

There's a difference between cleaning your fridge and sanitizing your fridge. Feist recommends a deep clean once a month to kill bad bugs. "People often use vinegar and baking soda, which aren't proven to adequately sanitize. But you don't want to use something particularly harsh or toxic to clean, because there's food in there," she says.

First, remove all the food and wipe down surfaces with warm, soapy water. Then apply a diluted bleach solution of one tablespoon of bleach to one gallon of water with a clean sponge and let it sit for a few minutes to allow the bleach to do its job. Dry with a paper towel or clean kitchen towel.

Up Next: This is hpw using an old sponge to clean the fridge can make you sick.

Wiping your fridge with any old dish towel or sponge is a terrible idea because it can harbor all sorts of icky bugs. One recent study even found E. coli on kitchen towels that had been used for one month without cleaning them. "If you have a set of kitchen towels and sponges, they should be washed in high heat or with a bleach solution once a week," says Feist. If you're in the kitchen often, especially with kids, she recommends changing out your towels every couple of days.

Read more: That lemon slice in your cocktail could make you sick

An investigation done by the BBC last year found fecal bacteria in ice at Starbucks and Costa Coffee shops in the United Kingdom. While your home's freezer isn't a hot spot like a public restaurant (and freezing foods does prevent new bacterial growth), any bacteria that does get into an ice tray can end up in your drinks. That means it's not a great idea to refill an empty ice tray and stick it back in your freezer. "If it's been handled, it could have come into contact with bacteria," says Feist. Instead, run ice trays through the dishwasher or wash with warm water and soap, then leave out to dry before filling and freezing.

Read more: 4 Fish Parasites That Can Make You Super Sick

Have you ever gotten sick from food that was improperly stored in your refrigerator? Are there any tricks you use to help keep your food safe? Let us know in the comments below!