Living life in the fast lane means using every possible convenience gadget to save time and energy. Let’s face it – who will use the manual mop and then vacuum when given the choice of using a 2-in1 mop and vacuum?
The same goes for food preparation. For those who want good meals without all the preparations beforehand and the washing up afterwards, ordering your favorite food is so simple. Heck, you can even order extra of your favorite food and stash away the extra helping in its “microwaveable” container in the freezer for another day’s meal.
Even if you are one of those who want to save the world and opt for reusable plastic containers, have you ever wondered what does happen when you place your food in plastic container and either cook it or reheat it in the microwave oven? Is there a difference between single and multiple use plastic containers?
According to National University of Singapore’s Associate Professor Suresh Valiyaveettil, based in the Department of Chemistry, the chemical structures of single use or reusable plastics are indeed the same. The difference is in the various thicknesses and melting points of the plastic containers, which depends on the amounts of additives incorporated, i.e., plasticizer and stabilizer, which are then processed differently.
Professor Valiyaveettil describes reusable plastic containers as “usually thicker, more stable, have a high durability and will be able to withstand multiple degrees of changes in environmental conditions”.
Dr Henry Leung, a senior specialist in Pharmacology & Toxicology attached to the Nanyang Polytechnic’s School of Chemical & Life Sciences, defines disposable plastic containers as having a lower density then the reusable types, i.e., making them less resistant to heat.
So, there are certain dos and don’ts that you should know, regardless whether you use reusable or disposable plastic containers in the microwave oven.
Other than the convenience of storage of food in the freezer, it is also very convenient to just take out the plastic containers and pop them into the microwave to reheat food. Here is where the dangers of this convenient practice come in.
According to Professor Valiyaveettil, since disposable plastic containers have lower density, i.e., they are thinner, the plastic will warp (lose its shape) in high temperature. Another issue that arises from warping is leeching whereby “small molecular additives” which give the container its durability and stability, turn into liquid and leak into the food you are going to eat.
Studies done on controversial additives like Bisphenol A (BPA) and phthalates, used in the making of plastic containers, have shown the chemicals to be harmful to human reproductive systems, our hormones and even infant developments. Even as it continues to conduct further risk studies on phthalates, the US FDA has claimed “BPA is safe at the current levels occurring in foods”.
If you decide that reheating food at a lower temperature will solve the warping and leeching problems, Professor Valiyaveettil has this to say, “leaching and solubility of the small molecules are linearly proportional to the temperature”.
He goes on to say, “While heating in a microwave oven, some of these small molecules leach into the food much faster than at room temperature.” In other words, leeching can even happen when hot food is dished out into plastic containers.
Professor Valiyaveettil’s advice is to refrain from reheating or cooking food in both disposable or reusable containers in the microwave oven. To be on the safer side, transfer freshly cooked hot food into glass, metal or ceramic metal dishes.
A few interesting pointers shared by Professor are summarized as follows:
- Keep plastic containers away from sunlight.
- Do not store highly acidic ingredients like vinegar or lemon juice in plastic containers.
- Buy containers with labels showing they are BPA or phthalate-free.
- Discard reusable or disposable plastic containers that are warped, as this is a clear indication the plastic cannot withstand high temperature, and leeching can occur.
To end off, hot cooked food is best dished out and stored in traditional dishes, i.e., glass, metal or ceramic. Use less plastic wherever possible to save our environment!
9th June 14:55