Q. I only have one microwave oven. How can I use it for both milchigs and fleishigs?
A. Best of course is to have two microwaves, one for milchigs and one for fleishigs. But if that is not possible, one should designate the microwave for one use or the other. Then, if for example, one needs to warm something milchigs in their fleishig microwave, they should double wrap the food. Unfortunately, this is not advisable for heating liquids in a microwave, because the buildup of steam will often cause the wrappings to burst. But dry items can be double wrapped, and even liquids can be double wrapped so long as they are only warmed.
One may use two plastic wraps or even a plastic wrap and a paper wrap. For example, one may place the plate of food into a Ziploc bag and then place that bag inside a paper bag. It is preferable that the microwave be wiped clean first. Similarly, in a non-kosher environment, i.e. an office, double wrapping a kosher product before using the microwave is the only way to guarantee the kosher integrity of the food.
This column comes from OU Kosher’s Halacha Yomis dedicated in memory of Rav Chaim Yisroel ben Reb Dov HaLevy Belsky, zt’l, Senior OU Kosher Halachic Consultant (1987-2016). Subscribers can also ask their own questions on Kashrus issues and send them to firstname.lastname@example.org. These questions and their answers may be selected to become one of the Q and A’s on OU Kosher Halacha Yomis.