Science Buddies: "Ask an Expert"

Hello,
i am working on a carbonated drink formula. the drink contains vitamins and heres. and will be carbonated.
-how to i pick the proper preservatives?
-hot do i make sure i chose the correct amount of preservatives?

Hello, This forum is for students in grades K-12 who are doing science projects. There are other more appropriate areas on the internet where you can get ideas. Thank you.