Can I use 马马虎虎 to describe food, and in what sorts of sentences can I use it?
To express a mediocre taste, I think it's better to say

這道菜［很普通/平淡無奇］。


馬虎 is generally used when we wish to comment on someone’s attitude. It may be used when you wish to criticise someone’s preparation of the dish as sloppy:

這道菜做得馬馬虎虎。
(lit.) This dish is done in a sloppy manner.


The sense 'so-so' (還過得去 in Cihai's definition), as in

這道菜，馬馬虎虎吧。
(lit.) This dish, it's so-so.

, is very colloquial, perhaps regional. It is found in Cihai but not in Taiwan dictionaries.