BATHTUB MOLD

Hi,

I just got my apartment professionally cleaned and they finally got rid of black and pink mold from my bathtub. How should I prevent it from coming back? I now theres those sprays to spray on the tub after you shower but i want to avoid getting chemical stuff cause im already sensitive to things and dont want to inhale it. Are there any homemade sprays or something that I could use?

I keep the vent on during the shower and leave the bathroom door open too

Thank you so much!