According to MongoDB docs: "if a document field contains the word blueberry, a search on the term blue will not match the document"

Text searches including an exact match phrase containing more than 1 word do not obey the above statement.

Related Stackoverflow question can be found here:
http://stackoverflow.com/questions/31659196/mongodb-full-word-search-with-exact-phrase-not-returning-expected-results/31951843#31951843