The Kefarian apple was a type of fruit of undetermined origin. They were notoriously difficult to keep fresh for more than three or four days. (CoE eBook: Ghost)

Kefarian apples was a key ingredient of a marinade sauce for Maltran sea-scallops served on the USS Enterprise in 2336. (TLE novel: Well of Souls)

This reference may have been intended to be Kaferian apples.