GE Microwave

The enamel (?) at the bottom of the Microwave has flaked off in two and three inch sections and rust is beginning to form over about 1 tenth of the bottom. Is it safe to wire brush and apply enamel? What brand and type would one buy to re-enamel? Is there a radiation hazard? Is food safe to eat? Is this a possible problem that GE should be responsible for? This is the second such machine we have owned with no similar problem with the first one.
Thank for your assistance. Regards, Will Surman