No, microwaving food does not make it radioactive. Microwaves work by using electromagnetic radiation at a specific frequency (around 2.4 gigahertz) to excite water molecules and other polarized molecules in the food, generating heat through friction. This heat cooks the food.
The microwaves used in household microwave ovens are non-ionizing radiation, which means they do not have enough energy to ionize atoms or molecules and create ionizing radiation (such as X-rays or gamma rays). Ionizing radiation is the type of radiation that can make substances radioactive.
Once the microwave oven is turned off, the generated heat dissipates, and there are no lasting changes to the food. The food does not become radioactive during the cooking process.
It's important to note that food can become contaminated with radioactive materials if it is exposed to radioactive substances, such as radioactive dust or fallout, but this is unrelated to the act of microwaving the food itself. Regular cooking processes, whether using a microwave or conventional oven, do not make food radioactive.