Your glazed ceramic plate probably isnโt coated with anything weird, but since itโs a matte glaze, itโs also not the best for food surfaces.
Mattes look matte usually because they are rough surfaces on a micro scale. They can be more difficult than gloss glazes to get thoroughly clean of food particles, and can hold on to odors and stains. I used to use a matte tea mug long ago that taught me this lessonโฆ I had chai in it a few times and then the spice smell never washed out.
I always glaze my pieces with a shiny glossy glaze on food contact surfaces. Let me know if youโd like me to make you something for your steaks sometime!