There has been lots of articles written on how strawberries may whiten your teeth. It is said that strawberries contain both Malic Acid and Vitamin C which can whiten and brighten your teeth. However, while the Malic Acid in strawberries may remove the surface stain of the teeth it also removes part of the tooth enamel, which once lost is irreplaceable. It is also said that the Vitamin C whitens the teeth by cleaning away the plaque buildup on your teeth and that the texture of the strawberry also helps in polishing the enamel of the teeth which gives it a smoother look. Truth is we need to be careful what we believe on the net as some things may do one thing, they may damage another. Obviously I would not ask you to stop eating acidic fruits and veggies as they have other benefits for our overall health, however be sure to always rinse your mouth after eating any acidic foods to minimize the damage to your tooth enamel and brush 30-40 minutes afterwards.
It has also been suggested by some professionals, including Dr. Oz, to mash strawberries with baking soda and placing them on your teeth with a toothbrush to get your teeth even whiter. DO NOT DO THAT! As mentioned above, strawberries are acidic and doing so, over time, the acid will cause erosion of the tooth enamel which is irreversible.