I have the same problem when I search the database, so I enter custom foods for almost everything. I only use the database for very basic items (mostly fruits, veggies, eggs, etc). The good news is that once you enter the custom food once, it's there for quick reference forever. I've been using fitday for about 4 years off and on, and I rarely add a custom food anymore. All of my staples are entered, and I know exactly what I'm getting. I don't think you're doing anything wrong with your search... fitday definitely needs to work on it.
Starting Weight: 150.4 (2-5-13)
Current Weight: 139.5
Goal Weight: 130 (5-31-13)