If you scan an item but find that the wrong food is returned, you can change the association of that barcode to the correct food in our database. Once you've scanned the barcode, scroll to the bottom of the food detail screen and tap "Not correct? Find a better match". Then type the name of the correct food into the search box. Once you find the correct match, tap on it and add it to your diary. This will change the association of that barcode to the correct food for all users, and the next time you scan that barcode, the correct food will appear.
Please note that if the correct item is not in our database, it must be added to the full public database of foods on MyFitnessPal before a barcode can be associated with it. Currently, foods added to your database using our mobile apps are not added to the full public database.