My cat food caught on fire

I have used Fancy Feast wet food for some time and the cats love it!

Higher in protein and water content, so it was great for my diabetic cat.   

Just recently (Dec 2013) I heated a can of gravy beef feast- mildly - only for 5 seconds - and there was sparking and crackling as if there were aluminum in the microwave.        Must have had some metallic or mineral substance in it, but I couldn't see anything like that.      I've heated this type of food before without any problems.

Not surprisingly, another can from the same box of cans caused one of my cats to throw up, get diarrhea, and now he has bladder stones.   Could be coincidence, but I'm concerned.      I don't want to have to switch foods but am afraid there is something they shouldn't be adding to the food that is causing this.

So much for "Gourmet" cat food.    Could this be one result of large food companies buying up the cat food companies?   Is quality slipping?

I have read these responses and I have a question.  When nuking the cat food, do you put the food in the cat's food bowl or do you just put the can in the microwave.  I think that would make a difference.

I fed my Rainbow Angel Misty canned food all her life and when it was refrigerated I also nuked it but first put the food in her bowl, not the can.  I never, ever had a problem. Of course she wasn't getting FF, she was eating Iams.

FWIW, I have reheated stuff with bone in it and that caused some sparking and some stews will also spark due to inconsistent dice size.