[header] How to maintain white teeth [title] Avoid or reduce exposure to highly acidic foods. [step] Acidic foods can weaken the enamel, and make teeth more likely to stain. This is part of the reason that coffee, tea, wine, and soda can all stain your teeth. 
Also make sure to wait at least thirty minutes before brushing your teeth after eating or drinking something acidic. [substeps] Fruits that are especially harsh on teeth include lemons and citrus.