grandson put foil bag in microwave and it started to spark is the food still food still good?!
When the flow of energy in the cooking cavity or inside the oven is disturbed by a metallic object it can cause a spark. Do not worry just try to avoid similar.
Not using foil in the microwave is part myth
You can read more on the USDA page on microwaves and food safety (link below); but here are the
General Rules for Safe Use of Aluminum Foil:
Use new, smooth foil only. Wrinkled foil can cause arcing (sparks).
Cover no more than 1/4 of the food with foil.
Shape the foil smoothly to the food so no edges stick out.
It makes no difference which side of foil (shiny or dull) is facing out.
Do not place the foil closer than one inch from the oven walls.
If the microwave oven has metal shelves OR a metal turntable, don't microwave food in foil containers or metal pans, and don't let foil used for shielding touch or be close to the shelves or turntable.
If you see arcing (sparks), immediately remove the foil shielding; transfer frozen food from foil container to a microwave-safe utensil.
If the foil hasn't stuck or burned on to the food there will be no contaminations from the metal. Cut of the parts that has stuck to the food and have a nice meal.
Microwave ovens burn the hell outta metal and can reach temperatures higher than the the stove in seconds depending on what the food looks like I could be okay.