I use the term encyclopedia rather than Wiki as I'm not sure of the best structure to choose.

I have thousands of food products with parent categories and grandparent categories and I would like to add them to my Wordpress website similar to a Wiki where people can register and amend or add new products.
A wiki was my first thought but I tried WPMUDEV Wiki and found the content to be quite disparate, i.e. it's hard to drill down through categories to the foods. Their particular Wiki is also based on virtual pages rather than actual Wordpress pages so it did not integrate with my theme. I have considered running a second website using their Wiki and a different more basic theme but it doubles my backend workload.

I'm looking for suggestions for a database/wiki that will integrate with Wordpress and inherit its' theme functions or lie within a Wordpress page using a child template or shortcode, similar to how many WP Forum plugins work. My membership controls are managed through Wordpress and S2 Members.

Suggestions for the hierarchical structure of the database are welcome too.