It's true.........Petals went through a terrible case of feline acne.........just a few months ago.........this was her after going to the vet and having to stay overnight.....
and I have used plastic for years - well for all my cats, with no problems, but I am manic about washing them and I only use anti-bac washing-up liquid,
I'm sure washing them after every use with an anti-bacterial soap has been part of your good luck. I use stainless bowls but the dish is never used more than once before cleaning in the dishwasher. I have 8 bowls for food plus a water fountain so having a clean bowl for each feeding is never a problem.