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Can You Microwave Plastic?

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Plastic materials have found their way into the modern kitchen in the form of serving utensils, cooking tools, and storage containers. When exposed to extreme heat, plastic can easily melt and warp, so is it safe to microwave plastic? 

It is not an easy question to answer. Plastics are synthetic materials that are made with a wide range of polymers such as PVC, nylon, polypropylene, etc. Plastics melt when heated, therefore they potentially leach harmful chemicals into food or liquids.

Food grade plastics have become readily available in the marketplace. Plastic is cheap, convenient and durable, therefore many people are using plastic containers, dishes and tools in modern kitchens, including the microwave oven. 

Are plastics and microwaves a bad match? Analyzing things superficially, several people make an uninformed decision. 

Let us explore the facts and find a convincing answer to the question whether or not you can you safely microwave plastic.

What happens if you microwave plastic?

When you microwave plastic, the plasticizers in the container may leak into food. Plasticizers refer to substances used to give the containers their shape and flexibility. 

Phthalates and Bisphenol are the most common plasticizers available today. When you expose a plastic container to high heat in a microwave oven, it melts and allows these softened plasticizers the come in contact with heated food and beverages.

Phthalates and Bisphenol may interfere with your endocrine system and cause damage. These substances are known as endocrine disruptors. 

If they reach your body in large quantities, you will become vulnerable to tumor and developmental disorders. Therefore, the initial conclusion is that everyone must be careful while using plastic in a microwave. 

That is exactly why the food-grade plastics are subject to strict regulations. Manufacturers of plastic containers are provided with detailed guidelines that need to be followed to get their products approved for microwave use.

Why does plastic melt in the microwave?

Plastic melts or warps when it comes into direct contact with intense heat and hot food. Certain ingredients such as fat and sugar have higher boiling point than water, therefore candy, cheese and meat can reach very high temperatures and cause the plastic to melt quickly. 

The quality of plastic is an important aspect because different types of plastic react to heat differently. As a result, plastics have many grades and useful purposes.

For safe food handling, you need to use food-grade plastic containers in a microwave to get the best protection against melting or warping.

How do you know if the plastic is microwave safe?

It is very important to know if a plastic container is safe to be placed in a microwave. Some products are highly resistant to microwave heat, but recognize that all plastic containers are not made equally. 

There are also plastic products that do melt or warp easily. If you microwave plastic that is non-compatible, you are compromising on both your health and environmental health.

Use the recycling code on the bottom of the container as a guide to decide whether plastic is microwave-safe or not. The number that is displayed at the center of a triangle embossed on a plastic container represents its recycling number. 

Different containers come with different numbers. These recycling numbers help you know whether a container is microwave-safe or not.

Can you microwave plastic?

Types of Plastic

To better understand which type of plastic is safe to use in a microwave, check out the recycling number on the bottom of every plastic containers. The synthetic material directly relates to the type of plastic used to make the product.

  • 5 is polypropylene, PP, and is considered to be food-grade plastic that is safe for microwave use. 
  • 1, 2, 4 are sometimes microwave safe.
  • 3, 6, 7 are not microwave safe

Let’s dive deeper into the different types of plastic to understand what the plastic recycling codes actually mean.

PETE-grade plastic

If you see 1 at the center of the triangle, that symbolizes the synthetic material is a polyethylene terephthalate or PETE-grade plastic. This type of plastic is advised for only one-time use. Generally speaking, it is not safe for microwave.


If you the number 2, you must understand that it belongs to the high-density polyethylene or HDPE category. There are mixed opinions about its use. Since there are no authentic studies about its safety, it is always advisable not to use this type.


The number 3 represents polyvinyl chloride or PVC. You will no longer find food containers made using this type of plastic. It contains a dangerous chemical known as Bisphenol A (BPA).


The number 4 stands for low-density polyethylene or LDPE. When you microwave plastic, nobody recommends this one. However, there are no convincing studies about its safety yet.


If you find number 5 in the triangle, the symbol is a polypropylene or PP grade plastic. This one is the best plastic option available for microwave use. Type 5 plastic is microwave safe because it has high heat-resistant properties and does not warp or melt easily.


The number 6 denotes polystyrene or PS. When you microwave plastic, you should not use a container made using PS. Furthermore, it is not recyclable and causes harm to the environment.


If you find number 7 at the center of the triangle embossed on a plastic container, you should know that it belongs to acrylic, polycarbonate, nylon, polylactic fibers, and fiberglass category. These types of products cannot be termed as microwave safe.

What is a microwave-safe plastic symbol?

One of the easiest ways to determine whether a particular plastic container is safe is to look for the microwave-safe plastic symbol approved by the FDA. This symbol comes with a picture of microwave and has 3 to 5 wavy lines inside signifying microwave energy. 

However, sometimes the symbol is not used, and the label clearly states “microwave safe.”

Either way, the markings are there to provide the consumer validation that the plastic has been tested and is approved for safe microwave usage. Labels are commonly displayed at the bottom of the plastic container and signifies that the product is safe to use in the microwave. 

Is BPA free plastic safe to microwave?

The Food and Drug Administration (FDA) clearly suggests that people should buy a container that is specifically labeled as “safe for use in the microwave.” 

In addition, recommendation have recently been extended to always look for the BPA-free label when it comes to purchasing a plastic container. The term BPA-free is further reassurance that the product is safe to come in contact with food and drink.

When it comes to nuking food in plastic containers, you should also make sure that you are choosing to microwave BPA-free plastic. Available in different categories, ratings, and variations, BPA-free plastic containers make the selection difficult for the uninitiated. 

You can select the polypropylene or PP grade plastic from the BPA-free plastic container choices available on the market. To be precise, Type 5 polypropylene (PP) is the best option if you want to microwave plastic.

That being said, Ziploc bags and Ziploc containers are made with BPA-free plastic. The manufacturer’s microwave instructions are vague at best, but the label mentions that the plastic should only be used to reheat or defrost, which implies that lower temperature settings should be used for short durations of time.

How long can you microwave plastic?

An FDA-approved, BPA-free plastic containers made using Type 5 polypropylene have been tested for up to 240 hours in the microwave before being introduced into the market. So, you don’t need to worry about it getting melted fast.

Plastic containers should never be exposed to heat more than the time specified by the manufacturer. Furthermore, you must avoid heating plastic several times a day without completely cooling down between each usage.

The Tupperware line of products are not designed for cooking in the microwave. The manufacturer instructions to microwave plastic Tupperware clearly state that foods should be reheated on medium heat for less than 3 minutes at a time.

Tips to Microwave Plastic

Microwaving plastic requires very cautious operations as a lack of knowledge can cause the microwave to malfunction, catch fire or leach harmful chemical into your food. 

Below mentioned are some of the tips that one can use to safely microwave plastic. These tips will help individuals to operate the microwave at its full potential and make sure that plastic containers are not causing avoidable harm.

  • Food grade plastic containers are the only type of plastic that should be used in the microwave. Look for type 5, BPA-free, microwave safe plastic.
  • For the best results, glass and ceramic are still the preferred option inside the microwave.
  • Never use metal components in the microwave. Plastic bowls, plates and utensils that are decorated with metal should be avoided as they are not microwave safe items.
  • Don’t allow the plastic wrap to touch the food. If you are using a microwave-safe plastic wrap, you need to make sure that it does not touch the food directly. It is always advisable to keep the food in a larger bowl to maintain some space between the plastic wrap and the top surface of the food. Steam will be trapped on the inside, and cause moisture that will inevitably drip into your food. Use caution when microwaving plastic wrap.
  • Avoid cooking a variety of foods at the same time. The reason being different food requires different time, temperature and heating techniques. Keeping all the food together for heating can cause trouble in taste and texture, which is easily preventable.
  • Use a lid over food while microwaving. Heating your food with a microwave cover can reduce heating time, promote even cooking and maintain moisture within the food.
  • Vent the lid half-open. Leaving the container lid half-open, you can ensure proper ventilation. This method allows steam to escape from the food instead of getting trapped inside the container. If the steam is trapped inside the plastic container, it may explode or scald you with steam when opening the lid.
  • Stop and stir the food. The process is very simple. For best results, simply open the microwave and stir the food every 30 to 60 seconds. Once stirred, again restart the heating process. Stirring promotes even cooking temperatures throughout the food and also reduces overall microwave time.
  • Keep a check on your food frequently while microwaving it. Different foods heat differently which is why you should keep an eye on the food while it is heating.
  • Make sure to heat food products till the time they bubble or steam. Reheated food in the microwave oven should be heated to a minimum internal temperature of 165 degrees Fahrenheit or 74 degrees Celsius.

Microwaving Plastic: Final Thoughts

Can you microwave plastic? Yes, you can microwave plastic safely if you buy an FDA-approved, BPA-free plastic containers made using PP food grade plastic. 

You need to have a clear idea about the different types of plastic containers available on the market. Moreover, you should know how to choose the best one from the abundance of choices. 

When it comes to performance and safety, glass and ceramic are the preferred options. Here are the best microwave safe containers for you to browse through the different possibilities available.

Lastly, it is necessary to strictly follow the guidelines of the manufacturer. Reduce the unnecessary risks and make your microwaving tasks hassle free, safe, and enjoyable.