In which food does fungi grow best?

Not sure: Fungi can grow in almost any live substance, some of which would be classified as foods. You can see it on breads, fruit, cheese, etc. Fungi can also grow on and in people -- both living and dead. Some feel that candida (which is a fungus) grows more liberally when fed by sugary, high carbohydrate foods. Sorry if this does not answer your question in the manner you wish, but it's my best try.