Is It Safe To Heat Plastic In The Microwave?

Packaging made from synthetic materials of organic origin, which consists of polymer, surrounds and facilitates domestic life. Therefore, it is common for many people to heat plastic in the microwave. Is it healthy at all?

We know that it creates molecular vibrations when heating food in the microwave as it changes the chemical composition. Likewise  , the microwave oven can also change the chemical composition of the containers we use – such as plastic. 

The debate is extensive and full of arguments for and against the use of microwave ovens. There are some who argue that the microwave is harmless with the right plasticity and knowledge of the properties of the food. This is what the World Health Organization (WHO) says, for example.

In this article, you can explore the types of plastics that are suitable, as well as the risks of using the microwave.

What types of plastic are there?

We classify plastic as natural or synthetic. Synthetic plastics include thermoplastics, thermosets and elastomers. According to the established coding, they are identified by a triangle with arrows, which is a symbol of recycling.

It is the international symbol for recycling, and inside this one will find a number from 1 to 7.

Types of plastic:

1. PET (polyethylene terephthalate):  Has many properties such as transparency and color acceptance. It is powerful, lightweight and easy to reuse. Many manufacturers use this type to package beverages.
2. HDPE (high density polyethylene): Flexible but with some stiffness. It resists chemical influences and high and low temperatures. It is colorless, almost opaque and easy to print, color or paste. It is commonly used to package food, cleaning products or engine oil.
3. PVC (polyvinyl chloride):  It is a very flexible and transparent type of plastic that many companies use for bags, laboratory containers or frozen food. It can be recycled into containers, bins and pipes.
4. LDPE (low density polyethylene): This type of plastic has a low recyclability and is used to a lesser extent in the food chain due to its easy tendency to release toxins. It is resistant to acid. Due to its hardness, it is used for pipes, plumbing, medical equipment, cleaning bottles and other applications.
5. PP (polypropylene): It is also hardy, thermally stable and easy to shape and color. We see it on plastic lids, packed lunches and diapers. It resists chemicals, boiling water and detergent. It is the only type of plastic that the WHO recommends for contact with food.
6. PS (polystyrene): We know this as plastic glass. It is hard and is used for food, toys and in laboratories.
7. Other (mixed plastic): A product that is difficult to recycle and which consists of several materials. We can find it in countless objects such as baby bottles, spout cups, medical containers, car parts and CDs.

What types of plastic are safe to use in the microwave?

According to the regulations and identification codes, microwave safe containers have the numbers 1, 2 and 5. Otherwise, they have a description that says they are “microwave safe”. Only these have a design that is okay to use in the microwave without altering their physicochemical stability and without toxic migration of particles. 

You should exercise caution with feeding bottles, as manufacturers have been making them out of polycarbonate for decades. This material releases bisphenol-A into the microwave oven, which is an endocrine disruptor.

There is currently a ban on producing them and companies are replacing it with polypropylene or

As you can see, there is a numerous variation of plastic and we tend to recycle it at home. In fact, we tend to take containers and use them to store food and drink in, even if they were designed for a different purpose, or at least not in a durable way.

In the same way we think because it is plastic, then we can briefly heat it in the microwave.

What are the risks?

Far from being inactive  , certain types of plastic release dioxins that are toxic and carcinogenic substances when we expose them to heat or cold. They penetrate food through a chemical process called migration.

Although some analyzes estimate that the migration process is overestimated, there is a mix of scientific arguments that require caution. Let’s take a look at some examples:

• If the packaging has the number 7, it  means that it contains bisphenol. In large quantities it  can be harmful to the body. It is an exogenous substance that, according to research, can contribute to obesity, endocrine changes and chronic, degenerative diseases.
• Those with the number 3 and the acronym PVC contain phthalates, which are chemical substances that are used as plasticizers. They  are harmful to health. 

• Never heat food in the microwave in plastic with the number 4 or PVC (polyvinyl chloride) or 6 or PS (polystyrene).

Another study revealed that a high percentage of people who regularly use the microwave oven do not know which plastic is right to use. Even worse is that they use any type of packaging and overheat the food. It increases the likelihood of migration of foreign substances from the surface of the material to the food.

Furthermore, living and working patterns that promote overheating of fatty foods only make the problem bigger. The migration is actually greater when we heat products with these characteristics and extend the contact time. 

Other options for not heating plastic in the microwave

If you do not have microwave safe plastic, you can use glass or ceramic that will withstand the temperatures of heating food without any problems. If it is only a few seconds, it will actually not pose a risk to use paper or cardboard – preferably white.

Among the best solutions are those made of silicone and pyrex glass, which you can use in both the microwave oven and regular ovens. 

You should never put metal in the microwave. Nowadays, however, it is permitted to use aluminum foil according to the manufacturers’ recommendations. You can even find microwave safe aluminum foil containers on the market.

Check the qualifications of the container if you want to heat plastic in the microwave

We recommend that you use the containers that the manufacturers have declared safe to heat in the microwave. According to standards, manufacturers must indicate the specifications of the type of plastic on the containers. It is then up to us to know and handle the information well.

If, on the other hand, you have difficulty recognizing the plastic that can safely get into the oven, you should go for glass or ceramic as a reservation.

You also have to decide if you need to cook or just heat it up. In the latter case, the time period is shorter. Whether it is plastic or glass, exposure will not be a problem.

That is not the case when it comes to cooking. In this case  , never use a container in the microwave that clearly indicates that it is not safe to use in the microwave. You should also avoid using containers that are deformed or very worn, as they are more likely to release chemicals.