Can You Put a Plastic Bag in the Microwave and Is It Safe?

Freezing food is easy when you are using a plastic bag. You might think that all you have to do the next day is pop the frozen plastic bag in the microwave to reheat or defrost.

Have you ever thought about whether this is safe?

As long as you leave the plastic bag open from the top by an inch, you can pop it in the microwave without a second thought.

The microwave-safe plate will catch any residue from the food as it defrosts, ensuring that no mess is made.

But, do not use high temperature as a plastic bag can melt in the microwave.


Can You Put a Plastic Bag in the Microwave?

Even though it is safe to put a plastic bag in the microwave, it must be kept in mind that plastic bags can melt at high temperatures. Hence, the food you are microwaving does not reach a high temperature; otherwise, the plastic will melt, and its residue will fall into your food.

Most storage bags at grocery shops are made of polyethylene with a melting point of 110-degree Celsius (1). This is usually okay since food in the microwave reaches a temperature of 74-degree Celsius when it is cooked (2).

If the food in the plastic bag takes a long time to cook or can get hot, we recommend not using the microwave.


Can You Put Ziploc Plastic Bags in the Microwave?

A common brand name, Ziploc, produces bags that can be bought from the supermarket.

They come with a plastic zipper and are great for freezing foods containing sauce or even fresh fruits and vegetables. The best part is that the zipper ensures that the food inside the bag is airtight so that different smells from the fridge do not find their way in.

According to the Ziploc company, it is okay to pop these plastic bags in the microwave (3).

But, you must open the zipper by an inch to allow air circulation. Moreover, you should be very cautious when getting the bag out of the microwave as it can burn you.

Many people worry about the chemicals in plastic bags that can contaminate food when it heats in the microwave. Yet, Ziploc claims that all its products are BPA-free (4).

This is a chemical that causes prostate cancer by imitating estrogen, damaging the body permanently (5). Ziploc bags do not contain dioxins either which have been known to cause cancer(4,6).

The plastic closures on the bag allow it to be opened and closed constantly. If you want Ziploc bags for fish and vegetables, you can buy microwave-safe Ziploc bags.

These are different from the usual plastic bags that the company makes as they allow steam to escape.


How Long Can a Ziploc Bag be in the Microwave?

When you pop a Ziploc bag in the microwave, the time set depends on the amount of food and how long it needs to defrost or cook.

Moreover, each microwave has a different power level so that needs to be kept in mind too.

What people misunderstand is that the food inside the bag matters more than the bag itself. The food determines how long the plastic bag can be kept inside the microwave.

If the food inside gets too hot and exceeds the limit that the plastic can stand, the bag itself can start to melt.

For example, when water reaches a temperature of 100 degrees Celsius, it starts to boil. This means that if the liquid or gravy you are heating in the microwave reaches this temperature, it will cause the plastic bag to melt.

We recommend never heating any liquid in a plastic bag in the microwave.

Not only is there a greater risk of leakage, but you could also burn yourself. Instead, pour the liquid from the plastic bag into a microwave-safe container.

Keep in mind that these are estimates.

One can never predict the exact temperature a plastic bag will melt since this also depends on everyone’s microwave and the power it has.

Hence, when you start heating your food, put the timer on for a lesser amount of time so that you can keep an eye on the contents of the bag.

Once the timer goes off, you can check the plastic bag and then heat it in short bursts. This will ensure that you do not overheat your food or cause the bag to melt.


Can Foodsaver Bags be Microwaved?

Like Ziplock, Foodsaver is another brand that creates plastic bags in a variety of sizes. These bags have a vacuum seal within the storage bag to ensure that food does not go bad in the freezer.

Based on the instructions given by the manufacturer, you can pop a Foodsaver plastic bag in the microwave when you want to defrost or reheat food (7).

However, do not cook foods in the microwave that have a high oil content or are raw. It is important to vent the bag so that steam can escape while your food cooks in the microwave.

Foodsaver bags are polyethylene bags with a bed of nylon outside. Nylon helps keep the bag strong and secure. But, these bags should not be used to boil food.

Instead, the company recommends using them for sous vide cooking, which means cooking food before it starts to boil.


Are Popcorn Bags Safe to Put in the Microwave

Since popcorn bags are made with paper, they are different from plastic bags and come with their own set of problems. Popcorn bags are said to have certain chemicals in them, including PFOAs, PFAs, and PFCs (8,9,10,11).

These are the same perfluorinated compounds that are common in Teflon non-stick products.

Studies have shown that these bags cause cancer in animals, but the jury is still out on whether food microwaved in these bags causes cancer in humans (12). Regardless, the American Cancer Society has announced that these bags come with a “potential” risk.

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How to Understand Which Plastic is Microwave Safe

Even though plastic bags can be put in the microwave if you are careful with the temperature, remember that greasy and oily food should never be microwaved.

This is because the oils can cause the plastic bags to release certain chemicals that you do not want in your food. Of course, there is a risk that the plastic could melt and leech onto your food.

However, we understand how easy it is to store food in plastic bags and then microwave those bags when you are ready for your meal.

You can check the FDA website to know more about the kind of plastic bags that are recommended for use. Moreover, every manufacturer must meet some FDA standards.

They have to test their bags in a microwave to ensure that they are not harmful to human health.

If the plastic bag meets all the FDA rules, you can safely put it in the microwave whenever you are ready to defrost your food. Look for the microwave safety symbol on the bag as a way to double-check.

After all, your safety is important!

If you cannot find any specific information on the plastic bag, do not risk popping it in the microwave. Constant use of unverified plastic bags in the microwave could lead to serious diseases, especially cancer.


The Side Effects of Plastic

There are many types of plastic varieties available in the market, each of which has different chemicals, including plasticizers, antioxidants, and colorants.

Experts believe that if guidelines are not followed, the chemicals in plastic bags can be harmful to health when put in the microwave. If exposure to chemicals continues for a long period, the effects on one’s health can be detrimental.

Everyone reacts differently to chemicals – what may not affect one person may be harmful to another.

Even though not all plastic bags are bad for your health, you must stay cautious. When you put a plastic bag in the microwave and allow it to heat for long periods, the content inside will melt, causing the plastic to melt.

When this happens, some chemicals will find their way into your food, becoming a health hazard.


In Conclusion 

Here are some quick tips for using plastic bags to microwave your food:

  • Only use bags that are microwave-safe.
  • Ensure that the plastic wrap does not make contact with your food.
  • Do not reuse a plastic bag once it has been put into the microwave.
  • Do not heat food high in sugar and fat in a plastic bag, as this will cause the bag to melt.
  • Do not use plastic packaging materials straight from the store as these can transfer chemicals to your food when put inside the microwave.
  • Remember to vent the bag so that steam can escape when your food is being heated inside the microwave.