A reader asks the following question:
“Is it safe to cook or reheat leftovers in the microwave oven?”
Please join this discussion and post your comments. I’d love to hear your thoughts. Here’s the answer . . .
Microwave Usage vs. Other Cooking Techniques
I don’t recommend using the microwave but, in honesty, there is very little to support my feelings on this one. So, let’s start with cooking in general.
First, any type of heating impacts the nutrients – sometimes bad, sometimes good depending on the food and the technique used. Higher heats cooking, whether it’s roasting, stovetop, slow cooker, or microwave, especially for longer periods of time or if submerged in water, causes the greatest amount of nutrient loss. (This doesn’t mean it’s time to jump on the raw food bandwagon though).
Second, there haven’t been any wide-scale, peer-reviewed journal studies on the impact of microwave cooking on food structures (at least that I can find). But, there was a small study on the effects of microwave cooking that is widely dispersed around the web which recommends not using the microwave due to the changes in food proteins. This study showed that the consumption of foods that had been heated in a microwave was followed by a short term decrease in the number of white blood cells in the study participants. Trying to write from fact and not feelings this study hasn’t been published in a peer-reviewed journal (although that doesn’t necessarily discount it’s findings).
Microwave Ovens and Food Safety
A definite area of concern when it comes to microwaves is food safety. Here there have been some good studies and they all show similar issues. Microwaves may not sufficiently kill various bacterias such as salmonella, streptococcus, listeria, and E.coli.
Microwave and Plastic
At this point it’s well documented that most plastics, including film food wrap, Styrofoam containers, and soft plastic containers’ particles migrate into the microwaved foods. Researchers who look at “invisible” changes occurring inside human cells (including metabolic patterns and nutrient ratios) find reason for broad-based concern about the use of plastic packaging in microwave ovens.
Microwave and Final Thoughts
My thoughts are that using the microwave oven is a risk I’m just not willing to take for me or my family. My husband and I tested the timing of reheating a dinner plate of food. I put the foods in a small steamer basket with a bit of water in a pot. My husband put the same foods on a plate in the microwave. Our results: it took 30 seconds longer to warm my food but the food heated in the microwave didn’t maintain a warm temperature through the meal. So, that’s how I’d recommend reheating your foods – a quick steam heat. This way you don’t have to worry about whether the proteins are changed in a microwave or if the food is safe to eat.
If you do decide to use a microwave oven, please make sure you use a proper container such as glass, Pyrex, and all microwave-safe ceramics.