Menu Close

Is It Safe To Heat Canned Food In The Can?

Share This Article

When you’re in a rush, you need to make lunch or dinner fast. You probably think that a canned meal is a good idea since it requires no prep. The big question, though – is it safe to heat canned food in the can or should you heat up the contents separately?

It’s not safe to heat canned food in the can. Heating steel cans could release chromium and nickel. You could be exposed to BPAs from the plastic lining inside of the can, as well. An unopened can might explode if you heat food items on a stove top. It could start a fire if heated in a microwave oven. 

Canned foods have been around since the 1800s. This method of food storage began in glass jars when the French offered an award to the person who could come up with a safe method of food preservation for their army during the Napoleonic Wars.

It progressed to preserving food in tin cans, which was expensive. A can of food had to be formed by hand and the cooking process took hours before the metal cans could be sealed. Because it was so pricey to can different foods, buying canned food actually became a status symbol during that time!

As a general rule, though, canning foods was more about feeding huge armies than it was about providing the best quality product. Eventually, soldiers were given more delicious food as a morale booster and this led to canned foods that were marketed to regular consumers.

In this article, we’ll talk further about heating up canned food products in the can, such as whether you should boil a can versus microwaving it. We’ll also discuss if it’s a good idea to eat canned food without cooking or warming it up first, so read on!

Can You Boil Canned Food In The Can?

The convenience of canned food is not solely for when you’re too busy to prep a home-cooked meal. These ready-made meals are also a favorite of campers and other outdoor enthusiasts. 

When spending time in the great outdoors, you may not have access to modern-day appliances like an oven, stove, or microwave. So, maybe you are curious about heating food over an open fire and boiling the contents of the can. 

Is boiling a can a safe and smart idea? Not really!

If you’ve decided to boil food in the original can because you’re worried about its potential bacterial content, there’s no need to. Before the food was canned, packaged, and shipped to your local grocery store, it was boiled already to kill off any microbes. 

This happens to all canned foods to ensure there is no health risk and they’re safe to eat. For some foods, such as seafood, they’re heated to temps higher than even what’s necessary for boiling (which is 212 degrees Fahrenheit) to kill bacteria.

What if you’re not concerned so much with bacteria, but more with just quickly and conveniently cooking your food? We still wouldn’t recommend boiling your canned food. Here’s why.

Most cans are made of stainless steel, which will contract and expand when exposed to temperature changes. Since boiling a can means heating it to temperatures of at least 212 degrees, if not higher, that’s going to cause the stainless steel to heat up and expand to a huge degree. 

What happens when metal expands and keeps on expanding? That’s right, it can explode. Now imagine the impact of canned soups or other foods heated to 212 degrees, boiling hot water, and shards of metal flying all over the place. 

The potential for injury is astronomical. The boiling water and food can cause serious burns and flying metal shards can slice and dice your skin. Let’s not even talk about what can happen if the metal gets close to your face or in your eye. 

Although we don’t recommend boiling canned food in the can, if you must (for example, in a survival situation), at least make sure you do it safely.

Take off the paper labels around the can and throw them away. Puncture at least two holes in the can. Use a can opener to open the top as well. 

These measures give the pressure and steam building up inside the can a place to escape. That could prevent the can from exploding. 

Can You Heat Up Canned Food In The Microwave?

Let’s say you are at home and you’re hungry for some canned food. You don’t really feel like heating the food on the stove because it will take too long.

Instead, you’d rather chuck the canned food in the microwave for 15 to 30 seconds (or maybe double that). Then, you’ll have a hot, steamy meal ready for you without any effort on your part.

While it sounds good in theory, microwaving canned food is very dangerous.. 

It doesn’t matter if the can is made of stainless steel or aluminum, it should not go in the microwave. No metal ever should. 

Metal will spark and even explode when microwaved, which can start a fire. Here’s a YouTube video that shows you what can happen. It’s scary stuff, right?  

Read our article on Kitchen Fire Safety Tips.

As the video illustrates, microwaving metal is bad news. Even though in the video, the man microwaves a balled-up piece of aluminum foil, trust us, the same thing will happen with food in a can. 

If anything, the pressure build-up from the expansion of the stainless steel could cause an even bigger explosion and thus possibly a fire. It’s just not worth it. 

Why Shouldn’t You Heat Canned Food In A Sealed Can?

If the risks of pressure-induced explosions, fires, and flying shards of stainless steel haven’t yet convinced you not to heat canned food in the can, we hope this section will. Besides the above safety risks, the following health risks are at play as well.

Metal Leaching

There’s a reason that food cans aren’t made of aluminum: it’s highly toxic! Stainless steel is less toxic, but still not totally safe. As we touched on in the intro, stainless steel contains two metals that can leach out, chromium and nickel. 

Chromium is a slightly blue metal that’s used in steel because it hardens it. You’ll see chromium plating on vehicles, especially the hubcaps and bumpers. 

Your body also contains some trace amounts of chromium. The metal allows for glucose to travel through the bloodstream to your cells so glucose can be converted to energy. 

Yet hexavalent chromium, which is used in industries such as welding and electroplating, can be risky for your health.

According to the Occupational Safety and Health Administration or OSHA through the United States Department of Labor, hexavalent chromium exposure can lead to significant health problems, such as:

  • Chrome ulcers
  • Allergic contact dermatitis and other allergic skin reactions
  • Nose irritation
  • Upper abdominal pain
  • Edema
  • Pulmonary congestion
  • Liver damage
  • Kidney damage
  • Respiratory irritation
  • Perforated eardrums
  • Eye damage
  • Asthma 

Nickel, which is also in stainless steel canned food, is added to prevent corrosion to the can even if it’s warmed to high temperatures. It can also be combined with chromium to create an alloy known as nichrome. Nichrome includes iron, manganese, and silicon as well. 

The Centers for Disease Control and Prevention or CDC states that nickel exposure can irritate the skin as well as affect the kidneys, stomach, and lungs. Prolonged exposure could even cause cancer. 

Admittedly, the amounts of both chromium and nickel that leach out of a stainless steel can are likely not enough to cause adverse health effects, but you can never be too careful! 

BPAs

As if all that wasn’t bad enough, Scientific American mentions that many food manufacturers will add food-grade epoxy to cans to further combat the risk of corrosion. The problem with this is that the epoxy is made of plastics that contain bisphenol-A, aka BPA. 

This chemical product has been in use since at least the 1950s and goes into many resins and plastic products today. 

The range of health issues that BPAs can cause is terrifying. Children and infants can exhibit behavioral issues from exposure. Fetuses might develop abnormalities in the prostate gland and brain. 

BPAs could also put you at a higher risk of developing cardiovascular disease, type 2 diabetes, and high blood pressure. 

What’s even scarier is that although some products state that they’re BPA-free, they might still contain the chemical. The only way to be completely sure is to examine the packaging for a plastic/resin identification code. You should do this for styrofoam containers, too.

The numbers 1, 2, 4, 5, and 6 are truly BPA-free. 

Read more home cooking safety tips for seniors.

Can You Eat Canned Food Right Out Of A Can (Without Heating It Up)?

The information in this article has you rethinking whether you should eat canned food again. Maybe instead of heating it up, you just open the can and eat the meal as is?

That’s very much a viable option. As we talked about earlier, canned food is pre-boiled to kill off bacteria, so you don’t have to worry about getting food poisoning or an upset stomach by eating cold canned food. 

Maybe the food doesn’t taste as delicious as it does when it’s warmed up, but it’s still perfectly edible. 

By the way, if you just can’t stomach the idea of munching on cold canned food, then the safest means of warming it up is to transfer the food from the can into a food-safe container. Then heat it in a microwave, oven, or on the stove top. 

Conclusion

Heating canned food in the can is a bad health and safety decision for a multitude of reasons. You could cause the can to explode or start a fire. Metals such as chromium and nickel can leach out, and anti-corrosive BPA resins could spell health dangers as well.

You’re much better off using a food-safe container to reheat canned food or even eating it cold! 

Join our email list for SeniorSafetyAdvice