Although the microwave saves a lot of time, many people have voiced concerns about its safety. Microwaves shoot electromagnetic radiation into food to heat it. Unfortunately, many items don't respond well to that radiation.
Certain foods may explode in the microwave, and some materials, such as styrofoam, may start a house fire if you warm up the wrong variety. Before you put anything else into the most common kitchen appliance, learn what isn't safe, clean, or practical to warm up in the microwave.
Aluminum Foil Is A Fire Hazard
Microwaving aluminum foil is a recipe for a fire hazard. The small electric fields spark through the foil, which may catch fire. Never put a large amount of aluminum foil in a microwave.
According to the USDA, it's safe to put a small amount of aluminum foil in the microwave to "shield" parts of food from heat. But don't cover more than 1/4 of the food, and make sure your foil isn't wrinkled. Creases in foil can cause arcing, which creates sparks.
Plastic Bags And Wraps Can Leak Chemicals
According to Dr. Russ Hauser, the Harvard chair of the Department of Environmental Health, plastic can be made from different materials. Depending on the type of plastic used, a bag or wrap may not be microwave-safe. Fortunately, the FDA requires manufacturers to test their plastic in the microwave.
The danger of plastic is that the chemicals could leak into your food. Because of that, Dr. Hauser recommends not heating plastic in the microwave. If you use plastic wrap, don't let it touch your food. And don't warm zip-locking bags, either.
Frozen Meat Can Reach The Danger Zone
Although defrosting meat in the microwave won't damage your kitchen, it may create a health hazard. According to the USDA, microwaving meat puts it close to the "danger zone." That's the temperature zone in which bacteria multiply, between 40°F and 140°F. Only microwave meat if you're going to cook it right afterward.
If you want to microwave meat before cooking, follow these tips from Health Canada. First, remove all packaging and transfer the meat to a microwave-safe container. Use a bowl or deep dish to contain the juices. Wrap it loosely with plastic wrap that doesn't touch the meat, and leave an opening.
Some Glazed Ceramics Aren't Microwave-Safe
If you buy ceramics from a reliable manufacturer, they're safe to microwave. However, beware of ceramics because some of them are not microwavable. Check the label before heating it up.
If you don't know how safe the container is, try a water test. Pour water into the container and warm it for 30 seconds. If the container is hotter than the water, then it's not safe to microwave. If the water is hotter, try it again for another minute.
Never Put Sponges In The Microwave!
According to a popular internet cleaning tip, microwaving a wet sponge will kill the germs on it. But it won't. A study in Scientific Reports says that microwaving a sponge may actually make the bacteria worse. The heat may kill some pathogens, but the worst bacteria will remain on the sponge--and multiply.
Bacteria thrive in warm, moist environments, like a wet sponge in a microwave. Heating a dry sponge is even worse; it could catch on fire. If your sponge gets dirty, throw it out and replace it.
Be Sure To Read Instructions Before Using Styrofoam Products
Contrary to popular belief, most styrofoam containers are microwave-safe. But not all of them are. Most takeout containers are not microwave-safe if they hold creams like mustard or butter. Don't heat foods high in fat, like ramen or soup, in styrofoam containers.
Always read the instructions before heating up styrofoam. If a takeout container says "one-time use only," don't microwave it. If you can warm up styrofoam, open the lid a bit to allow your food to vent. And don't keep heating after it boils.
Containers With Metal Handles
The USDA lists all safe and unsafe metals for microwaving. Unfortunately, most takeout containers don't adhere to the safety requirements list. Boxes with small metal handles should not be microwaved because they can burn the paper and start a fire.
Before microwaving a takeout container, remove the handles. Most paper is safe to warm up without the metal. When heating up food, never pair metal with paper, as that's a recipe for a house fire. You can always transfer the food before warming it.
Dishes With A Metal Trim Can Quickly Overheat
If your dish, cup, or bowl has a metal trim, don't microwave it. This includes dinnerware with gold, which was not designed to withstand high heat. The metal may overheat and create tiny sparks that will damage your microwave and dishware.
Most retailers who make silver, copper, or golden-laden dishes do not make them microwave-safe. But some newer versions have been built to handle microwaves. Always read the label before warming it up. When in doubt, don't warm it up--better safe than sorry.
Stainless Steel Travel Mugs Reflect Heat
If your travel mug is made with stainless steel, don't heat it in the microwave. The steel reflects heat and electricity, which could bounce back at your microwave and damage it. In the worst-case scenario, the steel may spark and catch fire.
Even if your stainless steel mug has a ceramic lining, it still isn't microwave-safe. In the best-case scenario, it won't even heat up your coffee. Since the metal deflects warmth, you'll end up with a cold drink and burning hot mug.
Hot Peppers Will Spice Up The Air Around You
Never warm peppers such as jalapenos, habaneros, or chilis in the microwave. No, it won't harm your kitchen, but it could injure you. The electric waves may release capsaicin, the active compound that gives peppers their spice. Then, the microwave fan may disperse the capsaicin, essentially pepper-spraying you.
The USDA adds that some vegetables can spark in the microwave, such as peppers. Experts believe that the minerals used to grow these vegetables may cause arcing. If your vegetable sparks, remove the part that was electrified.
Some Types Of Paper Are Fire Dangers
Not all paper is microwave-safe, according to International Microwave Power Institute president Bob Schiffmann. For instance, brown paper bags are never safe in the microwave. Since they can't handle a lot of heat, they may catch fire. Newspaper and any other paper with ink may leech into your food and contaminate it.
Wax paper, parchment paper, napkins, and paper towels are safe for the microwave. So are paper bowls and plates. Don't warm up dirty paper because that can spread germs to the rest of your food.
Baby Formula Does Not Heat Evenly
The FDA does not recommend microwaving breast milk or baby formula. Although baby milk is best served lukewarm, the microwave does not heat it evenly. When some parts are warmer than others, the hotter portions could scorch a baby's mouth.
You can microwave baby food, but you must do it correctly. Don't heat the food in a jar; transfer it to a microwave-safe dish. Heat it for a bit, stir it, and then heat it again for an even temperature. Always do a temperature test of microwaved food before feeding it to your baby.
Carrots And Other Vegetables Might Catch Fire
If you research methods for steaming vegetables, you'll see plenty of tutorials on how to microwave carrots. But over the past couple of years, reports have emerged of carrots that caught on fire. And it's not just carrots; kale, bell peppers, and green beans have also sparked.
Arcing is when the microwave's electric field turns into sparks. High-nutrient vegetables can intensify the electricity. Plus, the vegetables' shape may also conduct electricity. Cook your carrots on the stovetop or in the oven instead.
Microwaved Eggs Can Explode
Food with shells--including eggs, nuts, and seeds--will not survive the microwave. The heat builds up steam faster than the shells can ventilate it. Eventually, the food may explode. In April 2019, an English woman was sent to the hospital after a boiling egg exploded in her face.
Some sites advise people to prick the shell so that the steam can escape. However, the English woman did that, and her egg still exploded. Your safest bet is to keep shelled food away from the microwave, period.
Cooking Oils Won't Get Warm
If you want warm oil, you won't get that from a microwave. In fact, it's potentially very dangerous. Oils don't absorb microwaves as easily as water does, but will still get hot. According to Physics Forums, oil that's heated in a microwave can easily reach temperatures of over 400 degrees!
Defrosting butter in the microwave doesn't tend to work well. The ice makes heat oscillation difficult, so you're better off defrosting butter in the fridge.
Do Not Use The Microwave To Dry Clothes
Some people think that heating their wet clothes in the microwave will dry them. It won't--at least, not as well as a dryer. The microwave will heat water molecules outside and inside the fibers. If you warm the clothes for too long, they may catch on fire.
Plus, there is nowhere for the steam to go in a microwave. You may end up with damp clothes that are still wet in certain areas. Hanging them to dry for a day is far easier and safer.
Heating An Empty Microwave Actually Does Something Pretty Scary
Don't turn on an empty microwave. Although it may seem harmless, it can break the machine. With nothing to heat up, the microwaves will automatically go to the magnetron tube, which also supplies the energy source. If that goes on too long, it'll damage your microwave, say experts at the University of Illinois.
Some people discover this when they run their microwave accidentally. If you set a timer on your microwave, make sure that it isn't heating up. A couple of seconds won't damage it, but a couple of minutes might.
The Microwave Can Ruin Bread
This one isn't exactly dangerous, but you probably won't be happy if you put your bread in the microwave. People warm bread in a toaster for a reason. It's not just for the crunch; a microwave will ruin your bread.
After ten seconds, all the moisture will leave the bread. That's enough to leave a stale, dry, chewy mess... not exactly what you want from toast. Stick to the oven for bread.
Do Not Heat Food In Yogurt Or Butter Containers
It might seem clever to reheat food in an old container, such as a yogurt or butter cup. But these containers are not made for the microwave. It might melt, and--more importantly--leech dangerous chemicals into your food.
According to the World Health Organization, microwaved plastics can transfer chemicals into your food. These chemicals, mainly BPA and Phthalates, are added to make plastics stronger and more flexible. But they can interrupt your natural hormone production, so you do not want them in your food.
Always Put A Lid On Your Sauces
If you heat sauce in the microwave, it will splatter. This is because the heat gets trapped within the sauce. With nowhere to go, the heat explodes. According to the New York Times, sauces do not often catch fire, but they can damage your microwave.
If this happens, your microwave might not heat as well as it did before. To stay safe, put a lid over any food with sauce. Do not heat it for too long; warm it in 30-second increments. If it's pasta, stir it before you reheat it.
Why It's Unsafe To Reheat Leftovers Too Many Times
You can safely reheat leftovers within three to four days after first cooking them. But only microwave them when necessary. The USDA says that every time you microwave leftovers, the quality decreases.
According to the Food Standards Agency, you should be extra careful about reheating meats, seafood, sauces containing milk, eggs, beans, soy, rice, and pasta. These are more likely to decrease in quality after each microwave. Only reheat them when needed, and let any extra leftovers cool off before putting them back in the fridge.
Double-Check Your Travel Mug
Travel mugs are designed to keep your beverage warm on-the-go, but many are not suitable for the microwave. If your mug is made from stainless steel, do not microwave it! The steel soak up the heat and prevent it from reaching your drink. In the worst-case scenario, it might spark and harm your microwave.
If your travel mug is made from ceramic or plastic, check the label (usually on the bottom of the cup). If it's not there, check online. Companies will tell you whether or not their mugs are microwave-safe.
Leafy Greens Might Catch On Fire
Leafy greens--including spinach, kale, and beets--should never be microwaved. Mark Golkowski, an associate professor at the University of Colorado, told NPR that the vegetables can spark and cause a fire.
Why does this happen? One reason is the high amount of iron in these vegetables, mainly in dark ones like kale. The iron reacts to the electromagnetic field in the microwave. Plus, the shape of these vegetables often produce sharp edges, which threaten to catch on fire. Never warm these in the microwave.
Nitrate-Heavy Vegetables Can Turn Toxic
Most vegetables contain nitrates. Some, like carrots, celery, and spinach, have more than others. When these nitrates heat up in the microwave, they can turn into a carcinogen or cancer-causing chemical.
Nitrates can release toxins when reheated. It oxidizes and produces free radicals that can contribute to diseases. That said, you would have to microwave the vegetables quite a bit to create these carcinogens. But it's better to be safe than sorry; avoid reheating nitrate-heavy vegetables.
Reheated Rice Might Cause Food Poisoning
Although microwaving rice will not damage your microwave or cause a fire, it might produce dangerous bacteria. According to the National Health Service, uncooked rice contains the bacteria Bacillus cereus, which can cause food poisoning. Boiling rice will get rid of it, but Bacillus cereus thrives at room temperature.
If you do not reheat the rice enough, it can create more food poisoning bacteria. To stay safe, only reheat rice within a day after cooking it. Warm it until it steams, and only reheat it once.
Never Cook Potatoes In The Microwave
Cooking potatoes in the microwave will not make them edible like the oven or stovetop does. Potatoes contain a bacteria called Clostridium botulinum. This can cause botulism, an illness that might lead to paralysis or death. But the microwave does not kill this bacteria.
Since microwaves cannot eliminate the C. boltulinum, cooking potatoes in it will not work. If you reheat leftover potatoes, do not cover them in aluminum; it will block the heat. Loosely wrap them in a baking sheet and heat them until they are steaming.
Microwaving A Bottle Could Burn Your Baby
Although some baby bottles are microwave-safe, heating them up can still be risky. The rubber tip might melt or become lava hot. If the cap has BPA, it will leak into your baby's food, adding carcinogens to their meal.
Even if you remove all the rubber and BPA, the liquid will heat unevenly and might be scolding hot. If the bottle is closed, the steam will build up, and it might explode. Instead of microwaving milk or formula in a bottle, do it in a separate container, stir it, and then add it to the bottle.
Hot Pet Food Could Hurt Your Pet
You do not need to heat pet food. But if you consider it, do not microwave it. According to Primal Pet Foods, the microwave causes fat molecules in pet food to radically change. These fats become less easily digestible.
Vet Deva Khalsa also told the American Kennel Club that the microwave destroys nutrients in vegetables and grains. Over time, microwaved pet food can damage your pet's digestive health. If you pet does not want to eat cold or room-temperature food, talk to your vet about a safe heating method.
Microwaving Your Toothbrush Will Not Clean It
Some people believe that microwaving a toothbrush will clean it by killing bacteria. But this will only damage the brush, according to the American Dental Association. And if your toothbrush contains metal, it might spark or catch on fire.
Besides the fire risk, it is unlikely that microwaving a toothbrush will kill bacteria. Microwaves are not designed to sterilize, and they cannot destroy sponges or certain food bacteria. The microwave could even make the bacteria grow since they enjoy warm, wet environments. To keep your toothbrush clean, store it in a dry, airy place.
The Worst Ingredient To Clean A Microwave: Bleach
While cleaning your microwave, you might wonder if bleach can whiten the food stains. But you should not use bleach inside of the microwave. According to GloTech Repairs, bleach might damage the plastic walls, making them brittle. Plus, it is not as effective at killing bacteria as other cleaners.
If you leave some bleach behind and heat it, danger will ensure. The chlorine might evaporate, and these fumes are highly toxic. Instead of bleach, combine a few tablespoons of apple cider vinegar to a cup of water and use that to clean your microwave.
Pot Holders Can Handle Pot Heat, Not Microwave Heat
Pot holders are built to handle the heat of oven pans and pots. Some people might think that they can put pot holders in the microwave and then use them to take out the container. But if you do this, your pot holders--and your food--might catch on fire.
Most pot holders are made from cotton, which is dangerous to heat in the microwave. In addition, some pot holders have rubber seals inside for extra protection. These rubber parts can melt, and your holders will become unusable. Keep them out of the microwave.
Microwaving Your Pen Will Not Make It Write Better
When a ballpoint pen dries out, heating the ink will help it write again. But do not do this in the microwave. Unlike a lighter, microwaves heat objects from the inside-out. This can quickly become a disaster.
As the ink heats, pressure will build inside of the ballpoint pen. It might explode inside of your microwave, and the plastic might melt. This is not dangerous, per say, but it will become a hassle to clean up. In the worst-case scenario, the ink and pen shards might damage your micorwave.