Open Food Facts (Codename Smoothie) is the official app developed by Open Food Facts, which is available on Android and iOS. The source code is also available on GitHub.
Feel free to open a PR to add your application in this list. Please get in touch at reuse@openfoodfacts.org We are very interested in learning what the Open Food Facts data is used for. It is not mandatory, but we would very much appreciate it if you tell us about your re-uses (https://forms.gle/hwaeqBfs8ywwhbTg8) so that we can share them with the Open Food Facts community. You can also fill this form to get a chance to get your app featured: https://forms.gle/hwaeqBfs8ywwhbTg8