The Ultimate Guide To Microwave Safety

microwave safety

Everyone’s got a microwave these days, and it’s super easy to think it’s as harmless as an ironing board or a wooden spoon. The truth is… your microwave oven works by emitting electromagnetic radiation. If that sounds a bit scary, it’s because it is.

Firstly, these “microwaves” (or radio waves) are harmful if they come into contact with humans. Secondly, they work in ways that are very different from just making food hot like an oven.

To give one example…

Do you know why it’s so dangerous to put metal in a microwave? You’ll know by the end of this article!

It’s true that microwave ovens are designed with safety as a priority. But even still, there are 21 microwave-related hospital admissions across the US every day! That’s about 8000 a year!

Don’t become a statistic. Read on to understand exactly how you should be using your microwave and what precautions you and your family should take. By the time you finish reading, you can rest safe knowing that you won’t end up as one of the “21”.

Sound good?

Then let’s dive in!

Heat up to 167°F (75°C)

We reheat food for two reasons. Firstly, because it tastes better hot. And secondly, because bacteria and other undesirables naturally grow on food and heat kills them.

To kill all viral and bacterial pathogens you need your food to reach an internal heat of 167°F (or 75°C). That’s pretty hot, not too far from the boiling point of water.

Ideally, you’d use a thermometer to check your food is at a safe temperature. Realistically, make sure your food is piping hot. It should be too hot to heat just after it’s come out of the microwave oven.

You should be letting your food stand for a minute or two after using the microwave to let the pockets of heat dissipate. So if in doubt, overshoot it and give it an extra minute. This helps for safety reasons but will also mean your food is more consistently hot, too.

Heating it up to “warm enough” or “ready to eat” temperature might seem ok, but have a think about what might be growing on you or your family’s dinner for a second then get back to me. I think you’ll realize it’s worth waiting a touch longer.

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Make sure your food is spread out

As you (now) know, you need your food to be hot. The issue with microwaves is that the heat is not distributed evenly, but in bursts of waves that are strong in some points and weak in others. Moreover, these waves can only penetrate 1-2cm into food!

The solution is to make sure food is spread out where possible. Try not to have a big, dense clump of food in the middle of the plate as it will be hard for the microwaves to penetrate to the center and make it hot. If your food is spread out, the heat can pass through easily.

Some foods you can’t spread out, (baked potato, anyone?) so make sure these foods are cooked long and hot so the heat can spread through conduction.

Don’t use if the door doesn’t close

The inner frame of your microwave is coated with metal that reflects the microwaves (AKA radiation) back into the appliance so it doesn’t escape. Even the door doesn’t let the radiation out. It might look see through, but those small holes are designed to be too small for any microwaves to pass through.

So what happens if you leave the microwave running with the door open? You are literally letting radiation in the form of short wavelength radio waves out of the machine, ready to be absorbed by the nearest unfortunate human being. While it takes a substantial dose for any damage to occur, this should not be a risk anyone ever takes.

It must be said that microwave ovens are designed to only operate with the door closed. If this happens something is wrong with your device and you must not use it. Get it repaired pronto, or better yet, chuck it and replace it with something more reliable.

Never put metals in

Metal is NEVER microwave safe. You should make it very clear to all your family that this is an absolute NO-NO to put in a microwave, whether that’s a dish, fork, spoon, whatever.

Metals are full of spare electrons that are heated up and agitated by the microwaves (AKA short length radio waves) which cause the metal surface to get extremely hot and can cause sparks and bursts of flame. Check out this video for a demonstration.

If you want a fuller explanation with all the science behind it (good to show the older ones who are learning about science) then check out this great video.

What materials can you put in the microwave? Let’s answer that in the next section.

Check for microwave safe materials

The best dish, bowl or plate you can use in a microwave oven is anythnig that has the words “microwave safe” or the following symbol on it.

A manufacturer must make their products pass strict tests that are regulated by the FDA before they can use a “microwave safe” symbol. If you don’t own anything that’s labeled “microwave safe” then it gets a little trickier.

Ceramics, glass, and plastic are the best materials for a microwave as they allow the microwaves themselves to pass straight through without being absorbed or reflected. Unfortunately, each of these comes with its own issues.

With plastic, you run the risk of plastics that are harmful to humans leaching into the food and being consumed. BPA plastics are linked with a whole host of negative health conditions and exposing them to high temperatures from the microwave oven is more likely to see them end up in your food.

For ceramics, the potential danger comes from possible water content that can reach high temperatures from the microwaves. Ceramics also easily absorb heat through convection from hot food and burning hot dishes can be a hazard, too.

Be smart and look for the “microwave safe” symbol for peace of mind. Don’t have anything with this on it? Glass is the safest microwave material and your best bet in this case.

Test the heat of the food before trying it

One of the most common causes of microwave accidents is burns, either to the touch when holding burning hot dishes or on the mouth and tongue when eating.

Microwaves tend to focus their energy in certain spots of the oven and have less effect in other areas. This is why you have a rotating turntable in every microwave, to spread out the hot regions. Without it, your food would be burnt in a few spots and icy cold in others.

Even with the turntable, most microwave ovens are not perfect and have hot spots that cause burnt tongues and unhappy infants.

Let the food stand for a few minutes to allow the heat to dissipate throughout the food and test the heat of the food before swallowing a big mouthful. This way you’ll avoid a hasty post-dinner trip to the emergency room.

Don’t just pick up your container

The containers or dishes that you put in your microwave are ideally “microwave safe” (see tip #5), but that doesn’t mean you’re protected from burns to the fingers or dropping your dish because it’s too hot.

Microwave radiation will pass straight through a glass or ceramic container and cannot heat it directly. But as the food becomes hot, the container becomes hot be convection (transfer of heat, the way an oven works).

This can be deceiving and mean you pick up your microwave container when it’s actually burning hot!

How to avoid this? Well, plastic is the best material because as well as not absorbing microwaves it doesn’t absorb heat through convection very easily either. You definitely need “microwave safe” plastic though as otherwise dangerous BPA plastics can leach into the food.

Pierce your food / film lids

Due to the way microwave radiation concentrates on some areas of the oven more than others, you can get energy build up the leads to popping, bursting and splattering. This is especially pronounced in foods with higher liquid content or with film lids where steam can easily accumulate.

All microwave meals will tell you to pierce the lid. You don’t need to overdo it, a couple of times is enough to create a pressure release for excess steam to escape from. Fail to do this and you may just hear a few loud pops as your dinner is being cooked.

This can also be an issue with dense foods like a baked potato, which you should also pierce with a knife or fork to prevent steam build up.

Be careful of “super heated” water

One of the best “microwave hacks” is its ability to make boiling water in quick time without a kettle. Microwaves work by heating up water molecules so this is very energy efficient. At the same time, this poses danger in the form of “super heated” water.

When you boil water in a kettle on the stove you get visible signs of boiling like steam and fizzing at the surface of the water. Water that is boiled in a microwave however can appear still, like it’s a normal temperature, when it’s actually really hot.

This “super heated” water can make sudden jerks at the slightest disturbance which can easily result in burns if you’re not careful.

Don’t use it to thaw meat

The microwave radiation that heats up food and water in a microwave oven is quickly absorbed by dense foods, unable to penetrate more than one to two centimeters into any given food.

So if you’re trying to thaw a large chunk of meat, you’re likely to have burnt, half cooked edges and an ice cold center.

The last thing you need when cooking a chicken or pork dish when the center is frozen solid and you need to stick it in the oven.

Thawing meat is best done over a number of hours by naturally raising the temperature to that of room temperature. If you’re in an unavoidable hurry then chopping the meat into smaller pieces works as a fallback.

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Clean your microwave

When was the last time you cleaned the inside of your microwave? I’m willing to bet it wasn’t in the last two weeks (if it is, pat yourself on the back and skip this section!)

Foods that are heated in a microwave are renowned for spitting and bursting. These little splashes of food end up on the ceiling and wall of your microwave oven and are a perfect breeding ground for bacteria and other nasties that can find their way into future meals.

A quick wipe is all that’s needed to be safe in the knowledge that anything cooked in your microwave is free from unpleasantness.

What’s the safest microwave?

If you’ve managed to read this far then you’ve absorbed a solid 2000 words of safety-related material and it’s safe to say (pun intended) this is a big issue for you. In that case, you might wonder what is the best microwave for safety.

For my money, the top dog in the market is this model from Panasonic. This microwave oven has a hefty power output of 1200W so your food cooks fast with a range of size options, comes with loads of features including Panasonic’s patented Inverter Technology and things like Turbo Defrost, while also offering unparalleled safety.

Check out the link to see current price, reviews etc.