i know this is a super old thread but it's in my 'default' view as a newbie to the forum so thought I'd add my little bit of contribution just in case anyone else is looking for a food database!
I was researching a year back this same question... although I was looking for 1, 2 and 3 (See OP post)... and I came up with a few. These two though were the ones I was most keen on. Looks like one of these has already had a mention in the thread though... here for completeness
[mentioned in the thread above]
(download from here: https://www.ars.usda.gov/Services/docs.htm?docid=23634)
There is also a database here (if you read the text on the site it looks like a free app will qualify for free access to the database) http://www.nutritionix.com/api