There are many videos on YOUTUBE showing what will happen if to put things into a microwave oven heating. They are popular because that’s a question people care about. Even after watching some related videos, you may still not ensure it before an actual operation. A common question is, can I put a paper box or a paper bag in microwave oven for heating?
Many people love to prepare a sandwich at home, pack it with a brown paper bag and take it to their workplace as lunch. Or order delivery service, they usually use paper food containers too. If the food goes cold, you need to re-heat them; the microwave oven is the most convenient device.
Doing it according to the specification, transferring the food to a ceramic tray, then putting it into the microwave oven for heating is the most reasonable and safe way. But humans are always lazy. It will be more convenient to directly put the food into the oven with the paper package.
And is it safe?
The answer is not absolute.
We know that most metal products cannot be used directly in the microwave oven. Now some disposable aluminum foil trays are also microwaveable. There is a special coated on their surface, and it makes them can heat by the microwave.
Similarly, paper food bags and boxes are microwaveable theoretically; as long as they are totally made from paper. For example, some restaurants will use stapler nails for sealing paper food containers or with a foil liner inside. These metal widgets will break fire under microwave heating and burn the paper. It is very dangerous. Some plastic sealing tape will also meltage at a high temperature.
Besides, some heat-and-eat food packs in supermarkets need to prepare with a microwave oven, like the paper bag popcorn. It needs to be put in a correct way in the oven (the right side upwards,) or the corn may break out of the paper bag and dance in the room.
Some stagers often DIY popcorn at home. They put the corn in an SOS paper bag and put it into the microwave oven for heating directly. It needs to control the power and time well. You can search the recipe on the internet if you are interested in it.
Compared with these metal widgets, people are more worried about the effects on health if to microwave paper bags.
Some paper food packages have lots of colorful prints. The pigment they use may release something toxic under the high-temperature microwave, pollute the food, and affect health. In most situations, the inside of the paper containers, where contact the food directly, are printed-less. Even though the surface has patterns printed, they are all passed the safe test and won’t do too lousy harm to health.
Besides, almost all the paper food packaging is film-coated inside to prevent the food from conglutinating and give a grease and waterproof function. These coated are also food-grade safe; in some countries, they need to provide the related certifications like FDA. They won’t have any influence in a short microwave heating. But if heating too long, they may get meltage.
This question is relatively simple. Paper bags and boxes definitely can’t heat by an oven; they have a burn-up risk.
So why the paper muffin cups can be put in an oven for baking? That’s because they are made from special paper and have a higher ignition point. And the cake pulp is liquid, absorbs much heat during baking, reduces the paper cup temperature. But if it takes a long baking time, these paper cups will also burn up. Similarly, the ordinary using silicon paper for baking, even though its ignition point is 220℃, it will still burn up after 20 minutes of baking.
Anyway, to put the food with paper packages into a microwave oven seems not a good idea; much less in an oven. Suppose you are not in a hurry, to transfer the food to a microwave-safe tray for heating is always a good way. Especially you are not sure whether the paper package is safe.
Besides, one thing worth knowing is that in the USA, the USDA does not suggest using brown paper bags in the microwave oven.