It is safe to eat food that has sparked in the microwave.
Although the microwave sparked, the food is not harmed by the sparking of the microwave.
Sometimes some ingredients in the food may spark some randomly and other times it could be the dish that was put in the microwave that may have had some trace of metal on it or around it or it could be that the some of the paint inside the microwave is chipping and causing the sparking or even a damaged waveguide cover can also lead to sparking in the microwave.
As long as the food is not burnt, the food in the microwave that sparked is safe to eat and I've eaten food that sparked in a microwave before and it's been just fine.
If you use a damaged microwave it could result in potential fires, electrical problems and even microwave energy leaks.
If the microwave is damaged, especially if the door, seals or any internal components are damaged the microwave should not be used.
The microwaves that are emitted by the microwave magnetron could escape if the microwave has any damage to it's door, hinges, latches or seals.
Microwave radiation is often safe, but prolonged exposure to the leaking microwaves can result in skin burns or eye damage.
You can place a cell phone inside the microwave with the microwave off with the door closed and if the phone loses it's connection to the network it indicates a potential leak.
When your microwave makes a popping sound it could be due to a bug coming into contact with the magnetron or getting shorted out on some wires inside the microwave.
Or the popping sound from the microwave could also be caused by the food being cooked or the microwave itself.
Food that has a high fat or high water content or foods with skins such as potatoes when cooked in the microwave can pop as the steam escapes from the food.
Even food spills or residue that is left inside the microwave could cause a popping sound from the microwave.
In other cases the popping sound from the microwave, especially if the popping sound continues could be a problem with the fan motor, magnetron or even a bad waveguide cover.
Foods such as sauces, steaks and some vegetables can also pop as they heat up in the microwave as a result of the moisture in these feeds turning to steam.
And foods such as tomatoes, potatoes or even hot dogs, can trap steam in and pop when the pressure builds up as they cook in the microwave and the steam and pressure escapes.
And food splatters or residue inside your microwave can overheat and sizzle or pop.
A failing or faulty magnetron in the microwave can also produce popping sounds or buzzing sounds as the magnetron is what generates the microwaves that heat and cook the food.
A defective diode in a microwave which also works with the magnetron can also cause popping sounds.
And even the turntable motor that rotates the food and the cooling fan that helps regulate the temperature could make popping and scraping sounds.
If your microwave has any arcing it can be a result of a damaged or dirty waveguide cover or also a faulty magnetron which can create popping or sparking sounds.
Or if you happen to use a metal utensil or foil in the microwave it can create arcing and popping.
In some cases I've had my microwave pop and found out it was a bug inside the microwave that made contact with the wires or the magnetron.
If it continues then the microwave may be failing.