I just noticed that the metal part of my Philips sterilizer is rusty. anybody else has this issue? I've only used it for 3 months. is it harmful for baby?

It is normal in sterilizers. It is recommended to descale your sterilizer every 1-2 weeks to prevent it from being rusty. You must always unplug and wait for the sterilizer to cool down before descaling. Pour 80ml of white vinegar and 20ml of water into the water reservoir. Leave it there until the limescale dissolves. Pour away the solution and pour in clear water. Pour away the water and wipe the heating plate with damp cloth. Do not rinse it under tap water. In severe case, kiddy palace do sell the agent for descaling.