The Freebase team wrote about its open graph database, data cleanup tools, and APIs, before Google acquired it.
HN links it for Freebase's Graph API implementation, Gridworks (later Google Refine), and tagging, with commenters finding the data cleanup tools useful.
The way Facebook's Graph API is structured can be applied to other datasets containing interconnected objects. It's like a REST service serving JSON, with a specific way to construct the URLs. I like it a lot. Here is a blog post explaining the Freebase implementation:
http://blog.freebase.com/2010/04/29/a-freebase-implementation-of-the-facebook-graph-api/
The Facebook docs:
http://developers.facebook.com/docs/api
But even the cleanest API is of no use if the API calls don't actually work...
The apparently soon to be released Gridworks project from Freebase (http://blog.freebase.com/2010/03/26/preview-freebase-gridworks) looks like it could go a long way to help with data cleansing, especially with grouping and batch editing similar mis-spellings and such.
Freebase has some great info about food and drink: http://www.freebase.com/view/food You may find the following link useful to get a deeper understanding of tagging wrt freebase. http://blog.freebase.com/2009/06/10/common-tag-using-freebase-topics-as-tags/
née Freebase GridWorks http://blog.freebase.com/2010/11/10/google-refine-previously-freebase-gridworks-2-0-announced/