Reheating food is something we do every day. We open the microwave door, pop the faithful plastic cover we have been using for years, on top of the bowl or plate and push a button. A few beeps later we can enjoy our steaming hot food and a somewhat clean microwave. While this is a convenient process in our busy, fast-paced world, when plastic covers are constantly exposed to heat, the particles tend to break down and shed over time. Leading us to question, just how problematic this could be for both our health and also the environment.
A kitchen essential or a health hazard?
Microwave covers are useful, reusable items. They are used to retain food moisture and prevent food splatters in the microwave. They have become an essential item sold in any homeware store because they are inexpensive, as they are made from low-cost plastic materials, like polypropylene.
During the microwave heating process, plastic covers can release both microplastics and nanoplastics. Heat and moisture can cause chemicals to migrate from the plastic cover to the food, especially if the cover touches the food. A key chemical reaction occurs. The water molecules break the bonds holding the molecules within the plastic, creating small cracks. These weaken the containers which causes it to shed smaller plastic particles. One study found that some plastic containers can release roughly 4.2 million microplastics and 2.11 billion nanoplastics during only 3 minutes of microwave heating.
The problem? Two chemicals found in plastic are particularly controversial. Phthalates, used to soften plastics and bisphenol A, commonly referred to as BPA, which is used to make very hard plastic. Both BPA and phthalates are commonly found in plastics used for food containers, some plastic wraps and in the linings of food and drink cans.
Phthalates are hormone disruptors linked to health concerns such as reproductive problems, birth defects, and cancer while BPA, has been linked to the prostate cancer diabetes and cardiovascular disease.
Another popular choice when heating food is using cling film. Under EU law, unless a cling film is specifically marked as not safe for microwave use, it can be used to as a cover for food in the microwave. However, to ensure risk of transfer to food is kept at a minimum, make sure that your cling film isn’t in direct contact with your food.
A recipe for disaster?
When we consider all the plastic that can be found in the supermarket, it’s scary to think about the scale of which we are exposed to it. Microwaveable ready meals in a variety of cusines offer a quick solution to a hunger pangs. The market size of the prepared peal manufacturing in the UK was £4.2bn in 2023.
In Europe, just over 900 chemicals are permitted for use in plastics that come into contact with food. The words ‘microwave safe’ are supposed to mean the containers are made from materials able withstand the heat without releasing harmful chemicals. Specific migration limits are set to ensure substances used in these plastics do not exceed safe levels when in contact with food, especially after heating. However, there are concerns about data provided by the manufacturers themselves.
In an article published by the BBC Dr Diana Zuckerman, president of the National Centre for Health Research in Washington is quoted as saying; “When the manufacturer states that a container is microwave safe, that just means it won’t melt.”
Make the safer switch
Plastic covers and cling film may be labelled as ‘microwave-safe’ but that doesn’t mean that they aren’t harming our health. If we used less plastics we can help save our oceans too.
There are so many eco-friendly alternatives to plastic covers to choose from. Glass, ceramic plates and borosilicate glass lids are just some. You might already have some of these in your own kitchen, so have a dig around and help protect the environment whilst also looking out for yourselves too!