Raisin's translation into Spanish would be ***uva pasa*** or simply [***pasa***][1]. 
Raisins are known in Spain, and eating raisin stems is a folk remedy to improve your memory (http://forum.wordreference.com/threads/comer-rabo-de-pasa.1682011/). By the way, why are you assuming the translator is a Spaniard?


  [1]: http://dle.rae.es/?id=S4wqY0f