Hi I'm planning to sell my tea(brewed tea + sugar + lemon/fruit extract) product in bottles(Plastic or Glass) but since it's brewed tea it only last for 12hrs before funky smell comes out. Is there a way to preserve it so I can distribute it in bottles?
Given your recipe has fruit. I would make sure everything reaches a boil for 3 minutes, or at least a pasteurizing temp around 160°F, then bottle hot into mason jars.
Campden may be an option if boiling is not, but this doesn't kill yeast / bacteria. It only deprives the solution of oxygen inhibiting growth phases for microbes that require oxygen to do so.