Are you selecting the food so that it's highlighted in blue? The quantity option doesn't appear until it's highlighted. If you are already doing that, you may want to try using the tracker in a different web browser--doing that will tell us if it is a problem specific to that browser, or if it is another type of issue.
For searching for foods, you may want to try different combinations of the options below the tracker (search for any words, etc). I searched for those foods and found many entries for both. I think you're right though, that you will get used to it and won't have as much trouble.