I was wondering: have you spotted Open Food Facts as a database (with 4 million products). If so, any reason you chose not to use it @pobbypablo ?
The reason is that most apps use it, and it's full of inaccurate data. I actually tried to fix this by putting a considerable amount of time into building a smaller but more curated database.
On the other hand, when users add foods, only those with a high internal ranking will have their entries shown publicly. This helps keep the database cleaner.