Is cooking kosher food by a Goy - in this case me (doing giyur) in a microwave oven making the oven unsuitable for use by a Jew?
I asked one rabbi who said there is no halakhic issue. I live in a house of a very frum person (a hasidic rabbi, very much into kaballah, baruch hashem) and he always wants to turn the oven for me, so he has a part in the cooking. Does it come from kaballah - is goyish cooking able to damage the utensil?
Of course there is no milchig-fleichig mixing (everything is parve), it is not cooking for a Jew (bishul akum should not be a problem if only the goy eats what he prepared and food is cooked in a sealed vessel), furthermore everything has to be pre-packaged and brought to the kitchen unopened, has to have a reliable hechsher and the rabbi trusts the food I brought is kosher. Food is always cooked in sealed containers made of plastic. In my opinion there must be some kaballistic teaching about food prepared by a goy, being not forbidden (in this case), but undesirable for a Jew. Is there a halakha on this? What is the reason for this stricture?