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Heating Food in Non Kosher Microwave

I work at a Dayhab for developmentally disabled individuals. Some have MR (Mental Retardation), some have Autism, schizophrenia and more. There is microwave to heat up their food for lunch. People put in Milchiks and Fleishigs one after the other. In the past food that is completely treif has been put in there.

Is the microwave treif?
Can I use it?
Am I allowed to warm up the individuals food? I think most of them are Patur from mitzvos , but some might be mechuyav. It’s part of my job to do it, and it might cause me problems if I refuse. I’m not sure.
Is there a way to know which individuals are mechuyav in mitzvos and which arn’t?

Thank you.


There are certainly instances where because of developmental disability, a person is halachically exempt from performing mitzvos, and not held accountable for their aveiros. However, this is only with regards to their personal actions. In any event it would be forbidden to feed them non Kosher food or directly cause them to transgress any other aveira. This is known as the prohibition of ספייה בידיים, see Mishna Brura in siman 343 where he brings the various sources for this prohibition.

Extensive use of a microwave with non Kosher foods, as well as Milchig and Fleishig foods, would certainly compromise the kashrus of the microwave. This is due to the buildup of food remnants that are left and cooked together in the microwave, as well as the “blios” the flavor which gets absorbed in the walls by means of the steam generated by microwave cooking.

A sturdy microwave proof cover / container should be purchased and anything being heated up should be done inside this container, using a separate one for milk and for meat. If you are using just a cover, something should be placed underneath the food you are heating up [even if it is in a wrapper] such as a simple plastic plate. A sturdy covering like this will prevent the steam from transferring non Kosher into the food, and protect it from coming in contact with Non Kosher remains in the microwave. If this can be arranged, you can heat up all and any foods in the microwave.

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